JP2010042439A - Brazing method of combination type of convection heat and radiant heat, and brazing furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brazing method of combination type of convection heat and radiant heat for workpieces made of metal such as aluminum, copper, iron and stainless steel, the method causing no brazing defect due to prolonged brazing filler metal melting/retention time in a brazing step induced by temperature difference generated between the plurality of workpieces in a preheating step and remaining unreduced in a temperature raising step and also causing no brazing defect due to the mixing of atmosphere gas in the temperature raising step into the brazing step, and also to provide a brazing furnace. <P>SOLUTION: By effectively utilizing the action effect of the convection heat and the radiant heat so that the plurality of the workpieces receive equal amount of heat, a working space is soaked by the convection heat in the temperature raising step. Operation for reducing the temperature difference between the workpieces in a short period of time is performed using the radiant heat and the convection heat to further reduce the temperature difference in the brazing step, and defects by corrosion of a brazing filler metal which occurs by prolonged brazing filler metal melting/retention time is prevented. By a method in which an intermediate step chamber for checking the inflow of the atmosphere of a temperature raising step chamber to a brazing step chamber is installed between the temperature raising step chamber and the brazing step chamber, the occurrence of defective brazing and cavitation damage caused by deterioration in the working environment is prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for brazing a metal member (workpiece) such as aluminum, aluminum alloy, copper, copper alloy, iron and stainless steel using convection heat and radiant heat as heating energy, and a brazing apparatus therefor. In particular, the present invention relates to a furnace used for producing aluminum brazing products such as a heat exchanger, and a method for brazing a plurality of workpieces in the same chamber at the same time and the furnace.

  Conventionally, a brazing furnace frequently used for the production of aluminum brazing products is usually a tunnel type belt conveyor conveyance type. An inert gas such as high-purity nitrogen gas is introduced into the brazing work space inside the tunnel-shaped structural wall (muffle) in the furnace, and the dew point temperature and oxygen concentration in the work space are favorable for brazing. While adjusting to the environment, outside the structural wall (muffle), it receives the heating energy created by electric power or natural gas, etc., and the workpiece placed in the brazing work space as brazing temperature as radiant heat Built to heat.

  The brazing temperature varies depending on the metal material to be brazed, the brazing material to be applied, and the type of flux. Usually, it is 580 ° C. to 620 ° C. in the case of aluminum or its alloy, and 700 ° C. to 850 ° C. in the case of copper, iron and stainless steel.

  Fluoride is often used as a flux for brazing aluminum and its alloy workpieces, the working temperature is about 560 ° C., and the brazing temperature of the workpiece is 600 when the brazing material to be applied is JIS4343. In the case of JIS4045, it is 590-605 degreeC.

  The main brazing operations are composed of a preheating process, a temperature raising process, and a brazing process. The workpiece to be brazed is first heated to about 300-350 ° C. in a preheating process in a low dew point atmosphere such as dry air or inert gas while suppressing the growth of the oxide film thickness on the surface of the workpiece. After that, it is moved to a work space exhibiting an atmosphere environment controlled to a dew point temperature and oxygen concentration preferable for brazing with an inert gas such as high purity nitrogen gas, and proceeds to a temperature raising step and then a brazing step. The workpiece is heated to about 580 ° C. to 600 ° C. by the brazing process, and in a workpiece such as a heat exchanger, the brazing temperature is reached in about 1 minute to several minutes.

Usually, when the workpiece reaches the brazing temperature, brazing is performed while maintaining the atmospheric temperature of the working space at that time for about 2 minutes to several minutes.

  Conventional brazing furnaces that use radiant heat have the challenge of reducing the consumption of heating energy and high-purity inert gas in the form of a furnace, and convection heat is used as a new conventional technology to solve this problem of reducing energy consumption. There is a new conventional furnace that was devised by incorporating a part of the design concept of the energy-saving metal heat treatment furnace used. The furnace is composed of a drying chamber, a preheating chamber, a brazing chamber (heating step and brazing step), and a chamber connected in this order, and a plurality of workpieces are stacked on one tray. In a state, while being processed in each room, it is transported semi-continuously (intermittently) from room to room, and heated high-purity nitrogen gas or the like is circulated in the room as a heating medium inert gas by a fan or the like. And a brazing furnace to which a work piece is heated in a short time by convection heat.

  According to Patent Document 1, a heating medium inert gas is sprayed on a workpiece, and when the workpiece reaches a brazing temperature, heating is performed while finely raising and lowering the spraying temperature, which occurs between members constituting the workpiece. A pulse heating method and an apparatus therefor have been disclosed as techniques for improving productivity by shortening the brazing work process time by reducing the temperature difference caused by heat conduction.

  According to Patent Documents 2 and 3 and Non-Patent Document 4, as an improvement technique of Patent Document 1, a heating medium inert gas is intermittently injected into the brazing chamber in the workpiece temperature raising process and the brazing process. A furnace that shortens the brazing operation time by reducing the temperature difference between workpiece constituent members in a shorter time by using the pulse heating method of the above-described method is disclosed.

Published JP-A-2001-340958 Published Japanese Patent Laid-Open No. 2003-225761 US Patent US 6,693,263 B2 New Brazing Technology for Aluminum-Pulse Beck Brazing and Equipment-Light Metal Welding No. 488 (12-18 pages) Issued on August 16, 2003

Problems to be solved by the invention

  As a method for brazing a metal using convection heat, the present inventors have disclosed a new prior art disclosed in Patent Document 1, or Patent Document 2 or 3, in which a heating medium inert gas is directly applied to a workpiece in a timely and variable manner. It is a technique to reduce the temperature difference generated between the members constituting one individual workpiece by the effect of heat conduction, and it was verified in the actual furnace that the brazing time can be shortened Found that brazing products with brazing defects such as solder erosion, erosion, or solder breakage were mixed in the workpiece (brazing product) after brazing multiple pieces at the same time did. The following is a description of what we learned from investigating the cause of the defect.

  First, the erosion of the wax is because the atmosphere temperature in the work space in the preheating chamber (the chamber that heats the workpiece to 350 ° C.) is not equalized, so the temperature difference between the workpieces generated in the preheating chamber is reduced. In the temperature raising step in the brazing chamber (step of heating the workpiece to a brazing temperature of about 600 ° C.), it was found that it could not fall within the <specific temperature difference> described later. . As a result, it was transferred to the brazing process in a state where <specific temperature difference> was exceeded, and among the brazed workpieces, the brazing material was heated to reach the solidus temperature and began to melt. After the brazing temperature is reached after the brazing temperature is reached, a series of elapsed time (low melting residence time) from cooling until returning to the solidus temperature is determined from the behavior of the molten wax. A brazing erosion defect occurred in the brazed product that exceeded the time range.

<Specific temperature difference> is a control temperature difference for keeping the brazing melt residence time in the brazing process within a range in which no brazing defects occur, and each individual immediately before the transition from the temperature raising process to the brazing process. Refers to the temperature difference between the workpieces. If the melt melt residence time is too short or too long, brazing defects are generated. For this reason, in order to braze a plurality of workpieces within a predetermined process processing time, it is important to keep the brazing melt residence time within a range in which brazing defects do not occur. For this purpose, the atmospheric temperature is adjusted and maintained in the vicinity of the solidus temperature of the brazing material, and the temperature of each workpiece is within the range of the temperature difference (allowable temperature difference) that does not impair the brazing quality. The operation and time required for storage are required. Then, after the temperature difference falls within the allowable temperature difference, an operation of heating the stably maintained atmospheric temperature to the brazing temperature is required. When the workpiece is transferred to the brazing process in a state where the temperature difference in the temperature raising process does not fall within the allowable temperature difference range, and the temperature difference is reduced at the brazing temperature, the low melting residence time of a plurality of workpieces is reduced. Adjustment operations are not possible and defects due to wax erosion occur in brazed products that take a long time.

The brazing process corresponds to the frequent alternating change of the spraying temperature of the heating medium atmosphere gas during the brazing operation of the brazing material applied to the workpiece in the brazing process. It was found to occur by changing the temperature and changing the fluidity of the wax.

Furthermore, it has been found that solder breakage and solder erosion are caused by a deterioration phenomenon of the atmosphere environment of the work space of the brazing room. Workpieces that have been processed in the temperature raising process in the brazing chamber are subjected to the brazing process in the same brazing chamber, but the atmosphere gas in the work space of the brazing chamber is generated in the preheating chamber. When the workpiece is moved into the brazing chamber, the gaseous or invisible dusty floating substance that has flowed into the brazing chamber or generated during the temperature rising process of the workpiece (for example, the workpiece) Vaporized material from the binder that applies flux or powdered brazing material to the piece, or a floating residue of burned organic matter adhering to the workpiece). The deterioration phenomenon of the atmospheric environment refers to a phenomenon in which such a substance is mixed into the heating medium inert gas in the brazing process. The substance mixed with the heating medium inert gas adheres in contact with the flux or brazing material in a molten state, and as a result of hindering the action of the flux or brazing, it may cause brazing or erosion of the brazing. There was found.

On the other hand, when the flux begins to melt in the brazing process, the film thermal resistance value (heat conduction barrier) that hinders the heat conduction existing between the workpiece joining members starts to rapidly decrease, and the brazing material begins to melt further. Since the melted brazing material is filled in the gap between the joint surfaces of the workpiece and the member, the heat conduction barrier is wiped out, and the temperature difference between the workpiece members to be brazed is much faster than the heat receiving speed from the work space. Because of the rapid contraction due to the conduction action, it is not necessary to frequently adjust the temperature of the heating medium inert gas to reduce the temperature difference between the workpiece members from this point. It is important to prevent the occurrence of brazing defects by suppressing alternating fluctuations from abrupt, adjusting the ambient temperature to a temperature suitable for brazing in a timely manner, and maintaining stable at that temperature. It found that there.

The up and down variation of the spray temperature of the heating medium inert gas by the new prior art method affects the action of the wax that has started to melt. Regarding the fluctuating temperature difference above and below the spraying temperature or the fluctuating temperature difference between on and off, if the spraying temperature is too high at the top or on, the molten wax will be introduced to the inside of the member at the joint as the temperature rises. Since diffusion erosion is accelerated, it should be avoided to exceed the upper limit of the brazing application temperature range. On the other hand, when the temperature at the time of lowering or turning off falls below the temperature exhibited by the received workpiece, the fluidity of the wax is hindered, which may cause brazing defects such as brazing, and the workpiece exhibits. It is not preferable to set the temperature below. In addition, the range in which the heating temperature of the heated gas can be changed by the new prior art method is about 30 ° C. The effect of reducing the temperature difference between members is small with pulse heating of this degree of temperature difference, and the brazing time is reduced. I realized I couldn't expect a shortening.

Based on the above knowledge, the semi-continuous (intermittent) conveying heating method that brazes multiple workpieces according to the new prior art and its furnace can reduce the temperature difference between the workpiece components in the heating process. However, there is little work to reduce the temperature difference that has already occurred between the workpieces in the preheating chamber. In the brazing chamber, the temperature difference shown just before the temperature raising process is finished is the melting start temperature of the brazing material between the workpieces. Make a time difference in the elapsed time until it reaches. As a result, there is a delay in the time until the applied brazing material reaches the melting start temperature between the workpieces that are subjected to the process processing separated into the temperature raising process and the brazing process within a certain processing time in the brazing chamber. Arise. Due to the slow speed difference, the wax melt residence time can be made longer or shorter. This length determines the brazing quality. It has been discovered that a brazed product having a too long wax melt residence time has a drawback that even if it appears to be brazed in appearance, it actually produces a product with a poor quality.

In addition, substances in the atmosphere that interfere with the brazing action generated from the material applied to the workpiece in the heating process of the preheating chamber or brazing chamber are mixed into the atmosphere of the brazing process. Since the preferred atmosphere environment of the brazing process is disturbed, it has been found that the brazing product has defects such as brazing and erosion that can be seen from the appearance.

  The object of the present invention is a new prior art method of brazing generated in a furnace for applying a pulse heating method in which a plurality of workpieces such as aluminum, aluminum alloy, copper, copper alloy, iron or stainless steel are brazed at a time. Melt brazing intrusion and erosion at the joints, or breakage defects are eliminated, and solder breakage due to deterioration of the brazing atmosphere environment and erosion of the molten brazing are eliminated, resulting in a high yield of healthy brazing products. It is to provide a brazing technique and a brazing furnace that are useful for production.

Means for solving the problem

  Hereinafter, means for solving the problem will be described using the numbers used in (Best Mode for Carrying Out the Invention). These numbers are added to clarify the correspondence between the description of (Claims) and (Best Mode for Carrying Out the Invention). However, these numbers should not be used for the interpretation of the technical scope of the invention described in (Claims).

  The brazing method according to the present invention is a method of brazing a plurality of metal workpieces such as aluminum, aluminum alloy, copper, copper alloy, iron or stainless steel at a time. Consists of convection heat and radiant heat.

The present inventors have continued numerous tests on application temperature and its effect on radiant heat and convection heat used in a furnace for brazing a metal workpiece at a temperature of about 1000 ° C. or less where the required processing time is short. As a result, the effect of reducing the temperature difference while the radiant heat released from the work piece itself interferes with the transfer of heat energy to and from adjacent work pieces begins to be remarkable. I realized that it was when the temperature rose.

In addition, convection heat is generated between multiple workpieces in the preheating process based on the generally known knowledge that is effective in equalizing the working space temperature and increasing the heating rate of the workpiece. The temperature difference is adjusted by adjusting the ambient temperature of the work space soaked by convection heat in the temperature raising process, and the temperature of the heating medium inert gas is raised, lowered or stably maintained at a frequency of about 2 to 10 times. It was found that by performing the changing operation, the brazing quality can be reduced within a range not causing a defect.

Further, the radiant heat has an effect of effectively reducing the temperature difference between the workpieces in the brazing process in the atmospheric temperature region of 550 ° C. or higher. Further, the amount of convection heat supplied to the work space as the heating medium inert gas decreases inversely as a result of the volume expanding as the temperature rises in an isobaric state. Radiant heat complements convective heat that decreases with increasing temperature, and enables a stable supply of the amount of energy required for the work space. And, as a necessary condition for brazing, the change operation to adjust the atmosphere temperature of the working space to a temperature suitable for brazing in a timely manner and to keep it stable at that temperature has a small change temperature range and a small number of changes. It was found that it can be easily done by using both convective heat and radiant heat.

In other words, in the temperature raising step, the temperature difference between the workpieces and the temperature of the heating medium inert gas are set to a frequency of 2 to 10 times while mainly using convection heat and performing uniform temperature rising of the work space. In the brazing process, the temperature difference between the workpieces is further reduced by the radiant heat and the convection heat, and the temperature of the heating medium inert gas is set once. By adjusting the atmosphere temperature in the work space to a temperature suitable for brazing by a method of performing the change operation in a timely manner at a frequency of about 3 times, it is possible to suppress the variation in the wax melt residence time generated between the workpieces. It was discovered that the occurrence of brazing defects caused by the excessively long time can be suppressed.

On the other hand, the solder breakage caused by the deterioration of the atmosphere environment of the work space in the brazing process and the erosion phenomenon due to the flow of the solder are caused by the atmospheric gas in the preheating process or the temperature raising process. I noticed that it was caused by mixing into the atmosphere. As a countermeasure, it was discovered that an intermediate process was provided as a pre-process of the brazing process, and the atmosphere gas in the heating process was discharged in this process.

  Convective heat and radiant heat are generated as a heating medium inert gas by the heating source (205) of the heating energy generation chamber (203). This heating medium inert gas becomes a fluid that is variably adjusted in a timely manner by a circulation fan (206) such as a fan. This fluid gas passes through the heating energy circulation circuit (204), enters the heating energy introduction chamber (208), and is constituted by a gap between a pair of roll parts (109) while being subjected to flow adjustment at the rectifying part (210). The convection heat is supplied from the introduction hole (112) to the work space (209). On the other hand, radiant heat is received from the heating medium inert gas on the heating energy circulation circuit side of the radiant heat medium wall (202) constituting the heating energy circulation circuit (204) and the work space (209), and the work space (209) from the work space side. ) As radiant heat.

  The process of brazing is divided into three processes: a preheating process, a temperature raising process (a), and a brazing process (b). And it is preferable to provide an intermediate | middle process (c) between a temperature rising process (a) and a brazing process (b).

In the preheating process, a minute amount of moisture (humidity) that could not be removed from the workpiece in the drying process of the preparatory process that enters the brazing operation is prepared using heated dry air or inert gas to create a favorable atmosphere environment for brazing. It is a step of heating the workpiece to near the softening temperature.
In this step, there may be no special mechanism for reducing the temperature difference generated between the workpieces.

In the heating step (a), the heating medium inert gas temperature as the supply energy in the heating energy generation chamber (203) is appropriately increased or decreased, or the operation for changing the stability is limited to a maximum of 2 to 10 times. And adjusting the atmospheric temperature of the work space (209) to shorten the time required for the workpiece to reach <specific temperature (Ts)> and reduce the temperature difference between the workpieces. When the specific temperature (Ts)> is reached, the temperature difference between the workpieces is set within the <specific temperature difference (Td)>. The temperature of the working space (209) is soaked in a timely manner by increasing / decreasing the circulation amount of the heating medium inert gas with a circulation fan (206) such as a fan. The heating energy in this step is mainly convective heat.

The intermediate step (c) is a preheating step or a heating step (a) in which a gaseous or dusty floating substance that hinders the brazing action released from the workpiece to the work space (209) During the process of moving the piece from the heating process to the brazing process, this material is evacuated so that it is not present in the atmosphere environment of the work space in the brazing process. This is a step of adjusting the space (209) to an atmosphere environment preferable for brazing.

In the brazing step (b), the temperature of the heating medium inert gas is lowered from the initially set temperature at a frequency of about 1 to 3 times and maintained stably, and the temperature difference between the workpieces is changed. While further reducing the size, the atmosphere temperature in the work space is adjusted to a temperature preferable for brazing, thereby preventing the workpiece from becoming excessively long in the <low melting residence time (ht)>. The heating energy in this step is a combination of radiant heat and convective heat. Radiant heat supplies thermal energy to the workpiece, and convective heat is used to maintain a uniform temperature in the work space.

In the brazed product in which a plurality of the two working steps of the temperature raising step (a) and the brazing step (b) are produced at the same time, no defects due to intrusion or erosion of the molten brazing material are found. Also, there was no occurrence of a wax breakage defect caused by fluctuations in the fluidity. A furnace to which this method is applied can produce a product with higher quality than that applied to the new prior art method. Further, the intermediate process (c) can easily adjust the work space of the brazing process to an atmosphere environment favorable for brazing, and helps prevent the occurrence of brazing and erosion defects, thereby improving the brazing quality. Therefore, it is preferable to prepare between the temperature raising step and the brazing step.

  That is, in the metal workpiece brazing method of the present invention, at least in the heating step (a) and the brazing step (b), the heating energy supplied to the work space (209) is convection heat and radiant heat. The convection heat is generated by the heating source (205) of the heating energy generation chamber (203), and the heating medium inert gas becomes fluid by the circulation fan (206), and the heating energy is introduced through the heating energy circulation circuit (204). The chamber (208) enters the working space (209) from the introduction hole (112) formed by the gap between the pair of roll portions (109) while being subjected to the flow adjustment at the rectifying portion (210), and is convectively heated. The workpiece in the work space (209) is heated, and the radiant heat is generated by the heating medium inert gas on the flow path side of the heating energy circulation circuit (204) of the radiant heat medium wall (202). Receiving heat, heating the workpiece as radiant heat to the work space (209) on the work space side, and performing temperature increase / decrease operation of the flow rate of the heating medium inert gas to equalize the temperature of the work space (209). It has the feature in performing.

  Increasing the heat-receiving surface area, such as attaching fins to the heating energy circulation circuit (204) side of the radiant heat medium wall (202), which is a heat source of radiant heat as heating energy, places a workpiece at the ambient temperature of the work space (209). When the tray (110) is unloaded from the room with the opening / closing door (108) open or carried into the room, the atmospheric temperature of the work space (209), which tends to decrease due to heat outflow, is adjusted and maintained at a predetermined temperature. Since an effect (a heat retention effect in the work space (209)) can be expected, it is preferable to increase the heat receiving surface area on the heating energy circulation circuit (204) side.

The heating energy generation chamber (203) and the heating energy circulation circuit (204) are combined to heat the heating source (205) so that the radiant heat medium wall (202) can efficiently receive the radiant heat from the heating source (205). It is preferable to prepare for the position facing the radiant heat medium wall (202) by lowering to the region of the energy circulation circuit (204).

  The process of the brazing operation is performed in a work space (209) that is isolated from the outside air and in which the atmospheric environment is adjusted to a state suitable for brazing with an inert gas. The brazing furnace is divided into the order of the <preheating step>, <temperature raising step (a)>, <brazing step (b)>, and cooling step in each process chamber. Each process chamber (102; 103; 105; 106) is connected with an open / close door (108) in between. The temperature raising step (a) can be divided into a plurality of steps for the purpose of increasing the production volume, and the dividing step can be performed in the work space (209) of each chamber. Further, a process chamber (104) for performing the intermediate process (c) for the purpose of improving the atmosphere of the work space (209) in the brazing process (b) is defined as a temperature raising process chamber (103) and a brazing process chamber ( 105).

It is preferable that the preheating process chamber (102) has a structure of a chamber (103; 105) applied to the temperature raising process (a) and the brazing process (b) of the present invention.

The temperature raising step (a) is a step of heating the workpiece from the preheating step to the temperature just before the temperature of the flux applied to the workpiece reaches the melting point from the time of transition to the temperature raising step (a). Then, the temperature equalization of the work space (209) where a plurality of workpieces are placed and the temperature difference between the workpieces are reduced mainly by convection heat. A maximum allowable ambient temperature (Ta) of the work space (209) is determined, and the temperature of the heating medium inert gas is changed at a frequency of about 2 to 10 times below that temperature. ) To reduce the time required for the workpiece to reach <specific temperature (Ts)>, and when <specific temperature (Ts)> is reached, between the workpieces The method is characterized in that the temperature difference is reduced to <specific temperature difference (Td)> or less.

The shortening of the required time mentioned above is performed by changing the temperature of the heating medium inert gas supplied to the work space, thereby increasing, lowering, or stably maintaining the atmospheric temperature of the work space (209). The change operation is performed by changing the amount of heat received, such as the temperature indicated by the workpiece, the temperature difference between the workpieces at that time, detection information such as the temperature difference between the workpieces, the change operation timing, the number of times, or the adjustment value of the ambient temperature Determine operating conditions. Since the operating conditions differ depending on the shape, size, number, arrangement form, and the like of the workpiece, it is preferable to perform a simulation operation in advance before the main operation.

The allowable maximum temperature (Ta) of the ambient temperature in the work space in the temperature raising step (a) is preferably set to a temperature equal to or lower than the melting start temperature of the flux used for the workpiece.

It is preferable that the specific temperature (Ts) is determined such that the temperature indicated by the workpiece (w1) that increases the temperature most quickly among the workpieces to which the flux is applied is within the melting start temperature of the flux minus 10 ° C.

The specific temperature difference (Td) has a temperature difference of 25 from the temperature indicated by the workpiece (w2) that rises the latest when the workpiece that raises the temperature first reaches the specific temperature (Ts). It is preferable to set the temperature to be within ° C.

In the brazing step (b), the brazing material applied to the workpiece reaches the melting point (solidus temperature) and melts from the time when the workpiece moves to the brazing step through an intermediate step, and brazing is set. The process is performed until the temperature is lowered to the solidus temperature (Tk) by stopping the supply of energy when a predetermined time elapses after the heating to the temperature (Tz). In this process, radiant heat, together with convective heat, effectively reduces the temperature difference between the workpieces. It is characterized by a method of changing the heating medium inert gas temperature once to three times in order to adjust the atmospheric temperature preferable for brazing the workpiece and to maintain the temperature stably.

The allowable maximum ambient temperature (Tb) of the work space in which the workpiece is placed in the brazing process is determined in advance within the brazing temperature range <upper limit value (Th); lower limit value (Tw)> of the brazing material. It is preferable to set the attached set temperature (Tz)> plus about 10 ° C. to 20 ° C. and raise the temperature to that temperature for stable maintenance. Even when two or more kinds of brazing materials are applied to the workpiece, it is preferable to keep the temperature elevated to <brazing set temperature (Tz)> plus 10 ° C. to 20 ° C.

Next, from the point when <workpiece (w1) whose temperature rises earliest> reaches the brazing set temperature (Tz), the allowable maximum ambient temperature (Tb) of the work space is set to the brazing set temperature (Tz) plus 5 It is preferable to keep the temperature stable until the temperature is lowered to about 0C.

Next, from the point when <workpiece (w2) whose temperature rises the latest> reaches the lower limit value (Tw) of the brazing temperature, the allowable set ambient temperature (Tb) of the work space is set to the brazing set temperature (Tz) plus The time required for brazing (brazing holding time) is allowed to elapse while maintaining the temperature lowered to about 5 ° C. as it is. When the brazing holding time (Bt) elapses, the heat source of the supply energy is stopped, and the workpiece temperature is naturally cooled to a temperature equal to or lower than the solidus temperature (Tk) of the brazing material. As soon as the latest workpiece to be cooled reaches a temperature equal to or lower than the solidus temperature (Tk), the brazing process is completed and the process proceeds to the cooling process. The workpiece that is cooled most slowly may be the workpiece (w1) that is heated most quickly.

When the work space is provided as a process chamber isolated by an opening / closing door (108) for each process, the work atmosphere in the brazing process chamber (105) is affected by the inert atmosphere environment of the work space that affects the quality of the brazed product. It is preferable that the environment has the lowest dew point temperature and oxygen concentration in the space (209).

In the intermediate process chamber (104), in the preheating process chamber (102) or the temperature raising process chamber (103), a gaseous or dusty floating substance that interferes with the brazing action released during the process is transferred to the workpiece. During the movement of the piece from the temperature raising process chamber (103) to the brazing process chamber (105), the temperature raising process chamber (103) and the brazing process chamber are used as a process for preventing the flow into the brazing process chamber (105). (105) and is connected to a temperature raising process chamber (103) or an exhaust device such as an aspirator for discharging atmospheric gas from both chambers (103; 105).

  The brazing process chamber (105) is provided with a cooling process chamber (106) as the next process chamber. The brazing process chamber (105) is brazed each time the workpiece (brazing product) that has been subjected to the brazing process is taken out to the outside air. It is preferable to connect the working environment of the attaching process chamber (105) in order to quickly return the atmosphere environment to a required state. By providing this process chamber, the worker can enjoy a safe working environment. The cooling process chamber (106) may have the same function as the furnace of the new conventional method.

The invention's effect

  The metal workpiece brazing method of the present invention and its application furnace eliminate the brazing defects that occur in the new prior art method and enable the production of a plurality of brazed products having good quality at a time. However, since a significant reduction in energy consumption as a merit of the new conventional technology method can be realized, it can be provided to the market as an energy-saving furnace that replaces the conventional furnace.

  With reference to the attached drawings, the best mode for carrying out the brazing technique according to the present invention and its brazing furnace will be described below by way of an example of an aluminum alloy.

  FIG. 1 is a schematic configuration diagram of a brazing furnace 10 according to an embodiment of the present invention. The brazing furnace 10 is arranged in the order of a drying process chamber 101, a preheating process chamber 102, a heating process chamber 103, an intermediate process chamber 104, a brazing process chamber 105, and a cooling process chamber 106. Each process chamber includes an opening 107 at the front and rear of the chamber, and is equipped with doors 108a to 108g that open and close by opening and closing the opening 107. At the lower part of each process chamber, there are a plurality of roll portions 109a to 109f. The trays 110a to 110f carrying a plurality of workpieces are carried into the chamber, and the trays 110a to 110f are mounted during the process. And after the process, the trays 110a to 110f have a function of unloading.

A heating energy circulation device 111 is provided in the upper part of each of the preheating process chamber 102, the temperature raising process chamber 103, and the brazing process chamber 105, and a tunnel-like structure having openings in the upper and lower sides. 201 (in FIG. 1, reference numeral 201 indicating the position is omitted; shown in FIG. 2), and a work space 209 is constituted by a set of roll portions 109a to 109f for transporting the trays 110a to 110f. The pair of roll portions 109a to 109f has a function as a heating medium inert gas introduction hole 112 (in FIG. 1, the reference numeral 112 indicating the position is omitted; shown in FIG. 3) from the gap between the rolls. Yes.

The drying process chamber 101 is provided as a process for removing water adhering to the workpiece. If it is incorporated into a semi-continuous (intermittent) flow process, moisture may not be sufficiently removed from the workpiece, and sometimes it moves to the next process, resulting in defective brazing. The drying process chamber may be separated from the process chamber constituting the brazing furnace 10.

A fan device 114 for cooling the brazed workpiece is provided in the upper part of the cooling process chamber 106.

Further, in the temperature raising process chamber 103, the intermediate process chamber 104, the brazing process chamber 105, and the cooling process chamber 106, a high-purity inert gas introduction pipe 40 for adjusting the brazing atmosphere environment, and an inert atmosphere gas are provided. An exhaust pipe 50 is connected. (Piping is omitted from the figure)

Members exposed inside the chamber, such as the inner wall of the process chamber, the doors, and a set of roll parts that make up the interior of each chamber, flow in when the workpiece is carried in or out, or during the process from the carry-in material such as the workpiece Iron or stainless steel is used to prevent the dusty floating substances (substances that hinder brazing) from being released, including moisture, oxygen, or organic matter that hinders the brazing action, from adhering easily to the members of the room. The surface is covered with metal such as. The constituent members may be all made of metal, or may be covered with a surface treatment that cannot adsorb a material that hinders brazing. The structure of the wall in contact with the outside of each chamber is preferably made of a material that has a high heat insulating effect and is difficult to store heat. The open / close door is also made of a material that is highly effective for heat insulation from the outside air and between the process rooms. And the length of the connection direction of each process chamber other than an intermediate process chamber has the same dimension. However, since the intermediate process chamber 104 exhausts the atmosphere of the temperature raising process chamber 103 and prevents it from flowing into the brazing process chamber 105, the length of the chamber may be short if the function can be achieved. .

  FIG. 2 is a cross-sectional view of a process chamber used for the <temperature raising step a> and the <brazing step b> of the present invention, and FIG. 3 is a longitudinal view of the process chamber. This process chamber 103; 105 has a tunnel shape having an opening 107 at the front and rear, and has a bottom-open structure 201 having an opening 113 in the upper central portion and having the entire bottom as an opening. On the left and right sides of the space surrounded by the outside of the structure 201 and the inner wall of the process chamber, the heating energy generation chamber 203 and then the heating energy circulation circuit from the ceiling to the position of the left and right side walls (radiant heat medium wall 202) of the structure 204 is configured. A heating energy circulation device 111 that circulates the heating medium inert gas is provided in the upper part of the outdoor, and a variable rotation type electric motor is provided outside the room, and a circulation fan 206 is connected to the electric motor on the indoor ceiling. In the lower part of the room, a heating energy introduction chamber 208 is constituted by a space formed by a pair of roll parts 109 which are the structural parts on the indoor side of the roller type conveying device 207 having an operating mechanism outside the room and the bottom part of the indoor wall. . The work space 209 is composed of a space surrounded by the entire opening at the bottom of the structure 201 and a set of roll portions 109. A heating medium inert gas as heating energy is supplied to the work energy 209 in the heating energy introduction chamber 208. A rectifying portion 210 to be introduced is provided. An opening / closing door 108 is provided in the opening 107 for carrying in / out the tray 110 loaded with workpieces before and after the chamber. The radiant heat medium wall 202 is made of a material having high heat conductivity that can receive heat from one wall surface and dissipate heat from another wall surface.

  The flow of heating energy in the temperature raising process chamber 103 and the brazing process chamber 104 will be described with reference to FIGS. As a heating medium inert gas, energy obtained by heating a plurality of workpieces as convection heat in the work space 209 is recovered from the opening 113 at the top of the work space 209 to the heating energy generation chamber 203 by the circulation fan 206. . The recovered energy is introduced into the heating energy generation chamber 203 from the outside of the process chamber 103; 105 through the introduction pipe 40 to the heating energy newly supplied from the heating source 205 and to the generation chamber 203. The high-purity inert gas is regenerated into a heating medium inert gas adjusted to a preferable atmosphere for brazing. This heating medium inert gas flows as a fluid whose speed is adjusted by the circulation fan 206 and flows through the heating energy circulation circuit 204 while heating the radiant heat medium wall 202 on the circulation circuit side. 208 and flows into the working space 209 from the introduction hole 112 formed by the gap between the rolls of the pair of roll parts 109 while being subjected to the flow adjustment at the rectifying part 210. The flow of the heated gas flows as convection heat and flows out from the opening 113 at the top of the work space 209 while heating a plurality of workpieces stacked on the tray 110 in the work space 209, and generates heating energy. It is collected into the chamber 203. On the other hand, the energy received by the radiant heat medium wall 202 gives heating energy to the workpiece as radiant heat from the wall surface of the radiant heat medium wall 202 on the work space side.

In the temperature raising process chamber 103 and the brazing process chamber 105, a high-purity inert gas for adjusting to a preferable atmosphere for brazing is introduced into each of the process chambers 103; 105, and the volume corresponding to the introduced amount. The heating medium inert gas that circulates as much is exhausted outside the room. Since these exhaust gases each have thermal energy, it is preferable to reuse them.

Exhaust gas from the brazing process chamber 105 passes from the exhaust pipe 50b to the preheating process chamber 102, exhaust gas from the temperature raising process chamber 104 passes from the exhaust pipe 50a to the drying process chamber 101, and from the intermediate process chamber 104. The exhaust gas is preferably reused in the drying process chamber 101 by the exhaust pipe 51c.

An exhaust device 51, a backflow prevention device 52, and an on-off valve 53 are provided in each exhaust pipe 50 line from each process chamber described above. (Explanation of exhaust piping line is omitted)

  Next, the operation from the resting state of the brazing furnace will be described with reference to FIG. First, the open / close door 108 of the apparatus is opened with only the open / close door 108e located between the intermediate process chamber 104 and the brazing process chamber 105, and all other open / close doors are closed, and the temperature and atmosphere of the working space of each chamber are closed. Perform preparatory operations to make the environment ready for production. As soon as production is ready, the opened door 108e is closed and then production operation is started.

  The production operation procedure will be described by the movement of the tray 110 on which a plurality of workpieces shown in FIG. 1 are placed. First, the opening / closing door 108a that shuts off the outside air mounted on the front surface of the drying process chamber 101 is opened, and the tray 110a on which a plurality of workpieces are placed is placed on a set of rolls 109a in the drying process chamber 101 and carried. After loading, the door 108a is immediately closed. The plurality of workpieces are then subjected to a drying process. The atmospheric temperature of the work space during this step is preferably about 250 ° C. or less.

As soon as the drying process is completed, the door 108b between the preheating process chamber 102 located in the next chamber is opened, and the tray 110a on which the workpiece is placed is moved to the work space 209 of the preheating process chamber 102 (the tray 110a is 110b). Instead of the sign). As soon as the movement is completed, the door 108b is immediately closed and the preheating process is performed. The atmospheric temperature of the work space during this step is preferably about 350 ° C. or less.

As soon as the preheating process is completed, the door 108c between the heating process chamber 103 located in the next chamber is opened, and the tray 110b on which workpieces are placed is moved to the work space 209 in the heating process chamber 103 (tray 110b). Is replaced with the code 110c). As soon as the movement is completed, the door is closed and this process is performed.

The atmosphere in the intermediate process chamber 104 is obtained by introducing a part of the heating medium atmosphere gas in the brazing process chamber 105. Accordingly, the temperature, dew point temperature and oxygen concentration indicated by the atmosphere are almost the same level as the state exhibited by the brazing process chamber 105, but the intermediate process chamber 105 is equipped with a heating device to directly introduce high purity inert gas. You can also adjust the atmosphere.

As soon as the heating process is completed, the door 108d between the intermediate process chamber 104 located in the next chamber is opened, and the tray 110c on which the workpieces in the heating process chamber 103 in the previous chamber are placed does not move. The process processing of the chamber 104 is started. Next, while continuing the process in this chamber, the door 108e between the intermediate process chamber 104 and the brazing process chamber 105 located in the next chamber is opened, and the tray 110c on which the workpieces are placed is placed in the temperature raising process chamber. The intermediate process chamber 104 is passed from 103 to the work space of the brazing process chamber 105. When the tray 110c is unloaded from the temperature raising process chamber 103, the door 108d between the temperature raising process chamber 103 and the intermediate process chamber 104 is closed. Next, when the tray 110c passes through the intermediate process chamber 104 and moves to the brazing process chamber 105, the door 108e between the intermediate process chamber 104 and the brazing process chamber 105 is closed. The plurality of workpieces are subjected to a brazing process.

As for the opening order of the doors 108d and 108e, the door 108e between the intermediate process chamber 104 and the brazing process chamber 105 located in the next chamber is opened first, and the atmosphere temperature in the intermediate process chamber 104 is set to Even in the order of opening the door 108d between the temperature raising process chamber 103 and the intermediate process chamber 104 while heating at the atmosphere temperature of the attaching process chamber 105, the atmosphere environment in the temperature raising process chamber 103 may not be so dirty.

When the intermediate process is completed, the tray 110c has been moved to the work space of the brazing process chamber 105 located in the next chamber (the tray 110c is replaced with the reference numeral 110e). A plurality of workpieces are then subjected to a brazing process.

As soon as the brazing process is completed, the door 108f between the cooling process chamber 106 located in the next chamber is opened, and the tray 110e on which the workpiece is placed is moved to the cooling process chamber 106 (the tray 110e has a sign of 110f). Change). When the movement is completed, the door 108f is immediately closed and this process is performed. As soon as this process is completed, the opening / closing door 108g provided on the rear surface of the cooling process chamber 106 is opened, the tray 110f carrying the workpieces is carried out into the outside air, and the door 108g is immediately closed. Thereafter, a plurality of workpieces are loaded semi-continuously (intermittently) into each process chamber while being loaded on the tray 110 in the same operation procedure, and are unloaded after undergoing process processing.

  In the management of the atmospheric environment, particularly important processes are a brazing process chamber 105, an intermediate process chamber 104, and then a heating process chamber 103 and a cooling process chamber 106. It is preferable to adjust and control the dew point temperature of the temperature raising process chamber 103, the intermediate process chamber 104, and the brazing process chamber 105 during process processing to minus 50 ° C. or less and the oxygen concentration to 20 ppm or less. The cooling process chamber 106 may be adjusted to indicate an environment with a dew point temperature of −50 ° C. or less and an oxygen concentration of 20 ppm or less immediately before the completion of the process in the brazing process chamber 105. The preheating process chamber 102 may be an environment having a dew point temperature of minus 40 ° C. or lower and an oxygen concentration of 100 ppm or lower.

  Increasing the heat-receiving surface area, for example, by attaching fins to the heating energy circulation circuit 204 side of the radiant heat medium wall 202 serving as a heat source for radiant heat as heating energy, opens and closes the tray 110 on which the workpiece at the ambient temperature in the work space 209 is placed. Expected to maintain and adjust the atmospheric temperature of the work space 209, which tends to be lowered due to the outflow of heat when the door 108 is opened and carried out of the room or into the room (a heat retaining effect in the work space 209). Therefore, it is preferable to increase the heat receiving surface area on the heating energy circulation circuit 204 side.

Further, the heating energy generation chamber 203 and the heating energy circulation circuit 204 are combined so that the radiant heat medium wall 202 can efficiently receive the radiant heat from the heating source 205, and the heating source 205 is lowered to the area of the heating energy circulation circuit 204. Therefore, it is preferable to provide at a position facing the radiant heat medium wall 202.

  The adjustment of the atmospheric temperature of the work space 209 in the temperature raising step a and the brazing step b is performed by changing the temperature of the heating medium inert gas in the heating energy generation chamber 203. The change operation is performed by changing the atmospheric temperature of the work space. As an input, the temperature at the predetermined monitoring point before the change is automatically measured, the variable of the temperature of the heating medium inert gas is automatically calculated, and the variable is automatically corrected. It is preferable to use an apparatus having an automatic control function for adjusting the ambient temperature to the indicated value as an output. The temperature monitoring points are: (1) the ambient temperature of the work space 209, (2) the temperature of the radiant heat medium wall 202 on the work space 209 side, (3) the temperature of the heating energy generation chamber 203, and (4) the introduction of heating energy. From the temperature of the chamber 208 or (5) the temperature of the upper opening 113 of the work space 209, it is preferable to select one to three points as monitoring points.

  In the case of electric power, the heating source 205 is directly used as heating energy by an electric heater, and in the case of natural gas, combustion heat is used as a primary heat source and heat obtained on the secondary side through a heat exchanger is used as heating energy. it can. In the case of using natural gas, it is preferable that the heating energy generation chamber 203 is provided as a heating energy storage chamber 203a and a heating energy generation chamber 203b as an additional device.

  Furthermore, the process function of each process chamber is demonstrated. FIG. 4 shows an example of the relationship between the reduction in temperature difference between workpieces and the wax melt residence time by the method for adjusting the atmospheric temperature in the temperature raising step a and the brazing step b of the present invention.

First, since the workpieces are processed oil, fats and oils such as fingerprints, or organic substances contained in adhesives, etc., inhibit the brazing action. A plurality of trays 110 each having a circulation hole for the heating medium inert gas are placed and carried into the drying process chamber 101.

The drying process chamber 101 grows an oxide film covering the workpiece surface where the moisture remaining on the workpiece surface receives heat and rises in temperature. This growing film functions to hinder the brazing action of the brazing material. In order to eliminate this function, it works to remove moisture adhering to the workpiece while applying heat. Since the amount of adhering water varies depending on the shape of the workpiece, the time required for removal also varies. Therefore, it is not necessary to incorporate this process chamber 101 in a brazing furnace for brazing a large variety of small lot workpieces. It doesn't matter. In order to suppress the growth of the oxide film on the workpiece surface, the ambient temperature is preferably 250 ° C. or lower.

In the preheating process chamber 102, a very small amount of moisture remaining inside the structure of the workpiece, which could not be removed even in the drying process 101, is released into the work space 209 as the temperature rises. The moisture grows an oxide film on the workpiece surface. In order to suppress this growth, it is very important to reduce the moisture and oxygen concentration present in the work space 209. The environment of the work space 209 with the workpiece in it is an inert gas atmosphere, and the dew point temperature is minus 40 ° C. Hereinafter, it is preferable to adjust the oxygen concentration to be 100 ppm or less. Moreover, it is preferable to keep the atmospheric temperature which heats a workpiece | work with the intention of preventing softening of a workpiece | work as much as possible at about 350 degreeC. That is, in this step 102, the workpiece is heated at an atmosphere temperature equal to or lower than the softening temperature, and the atmosphere is preliminarily adjusted to make the work space 209 in each step after the next step a preferable atmosphere environment for brazing. To do.

At the time when the plurality of workpieces move to the temperature raising process chamber 103, the temperature difference between the workpiece w1 indicating the highest temperature and the workpiece w2 indicating the lowest temperature among the plurality of workpieces is Usually about 60 ° C.

In the heating process chamber 103, the energy for heating the workpiece is mainly convective heat. Due to the convection heat, the ambient temperature of the work space 209 is controlled within a range of ± 10 ° C. with no workpiece loaded. This atmospheric environment is preferably adjusted to a dew point temperature of −50 ° C. or lower and an oxygen concentration of 20 ppm or lower with the workpiece loaded. The allowable maximum ambient temperature Ta is preferably determined to be about several degrees C (5-7 ° C) below the flux melting start temperature (560 ° C.), and the temperature at which the workpiece w1 shows the flux melting start temperature minus about 10 ° C. is specified. Temperature Ts (550 ° C.), and the difference from the temperature indicated by the workpiece w2 when the workpiece w1 rises to the specific temperature Ts (550 ° C.) is defined as <specific temperature difference Td>. The temperature difference between the workpieces w1 and w2 is adjusted by adjusting the atmospheric temperature by changing the temperature of the heating medium inert gas to rise, fall, or maintain stable at a frequency of about 2 to 10 times in a timely manner. And the operation of keeping the specific temperature difference Td within 25 ° C. in a short time. When the specific temperature difference Td falls within 25 ° C., the temperature raising step “a” ends.

When the temperature raising step a is completed, the open / close door 108d between the temperature raising step chamber 103 and the intermediate step chamber 104 is opened, and the atmospheric gas from the temperature raising step chamber 103 is exhausted from the intermediate step chamber 104, and the temperature raising step is performed. The opening / closing door 108e between the intermediate process chamber 104 and the brazing process chamber 105 is opened while the atmosphere in the chamber 103 is purified in a short time, and the tray 110 on which workpieces are placed is transferred from the heating process chamber 103 to the intermediate process. Pass through the chamber 104 and move to the brazing process chamber 105. When the tray 110 is unloaded from the temperature raising process chamber 103, the door 108d between the temperature raising process chamber 103 and the intermediate process chamber 104 is closed.

Until the door 108d is closed, the high-purity heated inert gas is brazed from the high-purity inert gas supply pipe 40 in order to prevent the atmosphere from the temperature raising process chamber 203 from flowing into the brazing process chamber 105. It is preferable to maintain the required atmospheric environment in the brazing process chamber by flowing it into the process chamber 105. When the tray 110 moves to the brazing process chamber 105, the door 108e between the intermediate process chamber 104 and the brazing process chamber 105 is closed to complete the process process in the intermediate process chamber 104. It should be noted that even during the operation of moving the tray 110 from the temperature raising process chamber 103 to the temperature raising process chamber 105 through the intermediate process chamber 104, maintaining the set temperature of the atmosphere in the temperature raising process chamber 103 and the brazing process chamber 105, and the dew point It is preferable to adjust the temperature and oxygen concentration.

In the brazing process chamber 105, the energy for heating the workpiece is mainly radiant heat. Due to the convection heat, the atmospheric temperature of the work space 209 is controlled within a range of ± 5 ° C. with no workpiece loaded. This atmospheric environment is preferably adjusted to a dew point temperature of −50 ° C. or lower and an oxygen concentration of 20 ppm or lower with the workpiece loaded. The allowable maximum temperature Tb of the ambient temperature is preferably determined as a brazing set temperature Tz plus 10 ° C. to 20 ° C., and when the workpiece w1 reaches the brazed set temperature Tz, the allowable maximum ambient temperature Tb is set to braze. It is preferable that the temperature is lowered to the vicinity of the temperature Tz plus about 5 ° C. and kept stable at that temperature. By stopping the heat source of the heating medium inert gas after the elapse of the holding time Bt of about 3 minutes from the time when the temperature of the workpiece w2 reaches the lower limit value Tw of the temperature range defined as the brazing temperature, The temperature of the workpiece w1 is cooled to the solidus temperature Tk of the brazing material, and this process is completed. The adjustment of the atmosphere temperature in the work space in this step is performed in order to maintain a stable temperature at a temperature preferable for the brazing action, and the operation may be performed once to three times in a timely manner.

The cooling process chamber 106 serves to cool the brazed product to a temperature at which an operator can safely remove the brazed product from the tray, and moisture in the outside air flowing in from the carry-out port at the time of unloading is directly affected by the atmospheric environment of the brazing process chamber 105. It prevents the inflow to the atmosphere and quickly returns the atmosphere environment of the brazing process chamber 105 to a predetermined state.

Next, the contents of the embodiment will be described (related reference diagram: FIG. 4). Table 1 is the starting point of the test for confirming the results of the present invention. Table 2 shows the one at the time when the workpiece w1 that is heated up earliest reaches a specific temperature Ts (550 ° C.) on condition that the temperature is changed in the heating step a and the presence or absence of the intermediate step c. The wax melting residence time ht in the brazing step b is determined by the value indicated by the specific temperature difference Td presented to the workpiece w2 that is heated up late. The wax melt residence time ht indicates what judgment result is given to the quality of the brazed product. The new conventional method and the conventional method are also shown for comparison. From this determination result, it is shown that the brazing method of the present invention makes it possible to provide a brazed product having a quality comparable to that of the conventional method. The production amount per hour can be several times that of the conventional method.

It is a schematic longitudinal cross-sectional view which shows the convection heat and radiant heat combined use type brazing furnace of this invention. It is a cross-sectional view of the process chamber applied to the temperature rising process and brazing process of FIG. It is a longitudinal cross-sectional view of the process chamber applied to the temperature rising process and brazing process of FIG. It is a figure which shows one example of the relationship between the reduction | decrease of the temperature difference by adjustment of the atmospheric temperature in the temperature rising process and brazing process of this invention, and wax melt | dissolution residence time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Brazing furnace 101 ... Drying process chamber 102 ... Preheating process chamber 103 ... Temperature rising process chamber 104 ... Intermediate process chamber 105 ... Brazing process chamber 106 ... Cooling process Chamber 107 ... Loading / unloading exit 108a-108g of each process chamber ... Door 109a-109f that opens and closes the opening of each process chamber ... A set of roll parts 110a-110c; 110e; 110f ... Plural Individual workpiece stacking tray 111... Heating energy circulation device 112... Introduction hole 113... Opening 114 .. cooling fan device 201. ..Radiant heat medium wall 203... Heating energy generation chamber 204... Heating energy circulation circuit 205... Heating source 206. ... Heating energy introduction chamber 209 ... Work space 210 ... Rectification part a ... Temperature raising process b ... Brazing process c ... Intermediate process w1 ... Workpiece whose temperature rises earliest Piece w2: Work piece that is heated up the latest Ta: Maximum allowable ambient temperature in the temperature rising process Tb: Maximum allowable atmospheric temperature in the brazing process Ts: Specific temperature Td: Specific Temperature difference Tk: Solidus temperature of brazing material Th: Brazing temperature (upper limit)
Tw ... Brazing temperature (lower limit)
Tz ... Brazing set temperature ht ... Low melting residence time

Claims (24)

Concurrent convection heat with convection heat and radiant heat as the heat energy used to heat the workpiece in the chamber where at least the temperature raising process and the brazing process are performed in the process of brazing a plurality of metal workpieces simultaneously. Radiant heat combined brazing method. According to claim 1, the atmosphere after the process treatment flows into the work process for brazing from the chamber for performing the temperature rising process during the work of moving the workpiece after the process process to the chamber for performing the brazing process. As a process to prevent the convection heat and radiant heat combined brazing method, an intermediate process is newly added between the temperature raising process and the brazing process. The convection heat / radiant heat combined brazing method according to claim 1, wherein convection heat is mainly used as heating energy in the temperature raising step. The convective / radiant heat combined brazing method according to claim 1, wherein radiant heat and convective heat are used as heating energy in the brazing step. The convection heat and radiant heat combined brazing method according to claim 1, wherein convection heat is mainly used as heating energy in the temperature raising step, and radiant heat and convection heat are used as heating energy in the brazing step. 2. The temperature of the heating medium inert gas is 2 to 10 times less than the atmospheric temperature that is defined as the allowable maximum temperature of the work space for reducing the temperature difference between the workpieces during the temperature raising in the temperature raising step. Convection and radiant heat combined brazing method that adjusts ambient temperature by changing operation. In Claim 1, in the brazing step, further reduction of the temperature difference between the workpieces reduced in the temperature raising step and adjustment and stable maintenance of the work space atmosphere temperature in which the brazing material is in a molten state are performed once to once. A convection heat / radiant heat combined brazing method performed by changing the temperature of the heating medium inert gas three times. 2. The temperature of the heating medium inert gas is 2 to 10 times less than the atmospheric temperature that is defined as the allowable maximum temperature of the work space for reducing the temperature difference between the workpieces during the temperature raising in the temperature raising step. In the brazing process, the temperature difference between the workpieces reduced in the temperature raising process is further reduced, and the work space atmosphere temperature in which the brazing material is in a molten state is adjusted in the brazing process. A brazing method using both convection heat and radiant heat, in which the atmospheric temperature is adjusted by changing the temperature of the heating medium inert gas one to three times. The convection heat / radiant heat combined brazing method in which the allowable maximum temperature of the working space ambient temperature is set to be equal to or lower than the melting start temperature of the flux and the ambient temperature is adjusted at a temperature equal to or lower than this value. In claim 6, the allowable maximum temperature of the working space ambient temperature is determined as the melting start temperature of the flux minus 5 ° C. to 10 ° C., and the convection heat and radiant heat combined type brazing that adjusts the ambient temperature at a temperature below the determined value. Attaching method. 8. The combined use of convection heat and radiant heat, wherein the allowable maximum temperature of the working space atmosphere temperature is defined as a brazing set temperature plus a temperature of 10 ° C. to 20 ° C., and the ambient temperature is adjusted at a temperature below the determined value. Brazing method. In claim 8, in the temperature raising step, the allowable maximum temperature of the working space ambient temperature is determined to be equal to or lower than the melting start temperature of the flack, and the ambient temperature is adjusted at a temperature equal to or lower than the determined value. A convection heat and radiant heat combined brazing method in which the allowable maximum temperature of the working space ambient temperature is determined as a brazing set temperature plus 10 ° C. to 20 ° C., and the ambient temperature is adjusted at a temperature equal to or lower than the predetermined value. The convection and radiant heat combined brazing method according to claim 12, wherein in the temperature raising step, the allowable maximum temperature of the working space atmosphere temperature is set to a temperature at which the flack starts melting minus 5 ° C. to 10 ° C. In claim 6, when the maximum temperature difference between a plurality of workpieces is reduced to 25 ° C. or less, the workpiece is transferred to a brazing process and the brazing process is performed. Method. In claim 8, when the maximum temperature difference between a plurality of workpieces is reduced to 25 ° C or less, the workpiece is transferred to a brazing process and the brazing process is performed. Method. In the furnace applied to claim 1, the work space for processing the workpiece is inside the tunnel-shaped structure inside the process chamber, and the gaseous fluid is supplied from one of the wall surfaces of the structure to the wall surface. A convection and radiant heat combined brazing furnace characterized by a structure having an opening for flowing into the interior and flowing out from another remote wall. The convection heat / radiant heat utilizing brazing furnace according to claim 16, wherein the structure is made of a material having a function of receiving heat from one of the wall surfaces of the structure and dissipating heat from the opposite side. The brazing furnace using convection heat and radiant heat according to claim 16, further comprising a functional part that increases a heat receiving surface area of the wall surface of the structure. The brazing furnace using convection heat and radiant heat according to claim 16, wherein a heating source is provided at a position opposite to the heat receiving surface of the wall surface of the structure. The convection and radiant heat combined brazing furnace according to claim 16, wherein a heating energy generation space and a heating energy circulation circuit are provided in a space surrounded by the exterior of the structure and the indoor wall. The convection and radiant heat combined brazing furnace according to claim 16, further comprising a rectifying portion that regulates the flow before the opening into which the gaseous fluid flows. The opening part which is equipped with opening and shutting doors in the front and back of the room and carries the workpiece in and out of the room wall according to claim 16; the inside of the opening is a tunnel shape, and convection heat is introduced from the bottom part to the center part and the bottom part of the ceiling A structure having an opening to be discharged from the upper part; a radiant heat medium wall in which both vertical sides of the structure receive heat energy and a heat radiating surface; function as a tray for carrying workpieces in the lower part of the chamber and a frame A set of roll parts constituting a roller-type conveying device provided; on the ceiling of the room, a fan for circulating a heating medium inert gas connected to a rotary electric motor placed outdoors; a rectifying part at the bottom of the room, heating A heating source that generates energy, and a high-purity inert gas introduction pipe to the indoor heating energy generation chamber and an inert atmosphere gas exhaust pipe to the outside,
Work space enclosed by the inner wall of the structure and a set of roll parts; heating energy generation chamber from left and right upper spaces partitioned by the upper surface and part of the outer wall of the structure and the inner wall of the furnace; radiant heat medium A heating energy circulation circuit in a space from the lower side of the heating energy generation chamber to the position of a set of roll parts; heating energy surrounded by the bottom of the room and a set of roll parts from the heating energy generation chamber. Introduction chamber: An introduction hole for sending heating energy to the working space is formed in the gap between a pair of roll parts,
The heating medium inert gas is adjusted to the specified temperature, dew point temperature, and oxygen concentration with the heat energy produced by the heating source provided in the heating energy generation chamber and the high purity inert gas introduced from the introduction pipe into the generation chamber. Then, it is sent to the heating energy introduction chamber through the heating energy circulation circuit by the circulation fan, receives the flow adjustment at the rectifying part, and flows into the working space from the introduction hole constituted by the opening of the pair of roll parts. The workpiece is heated as convection heat and circulated again from the upper opening of the work space to the heating energy generation chamber. On the other hand, by heating the side of the heating energy circuit of the radiant heat medium wall, the radiant heat medium wall becomes radiant heat, A convection and radiant heat combined brazing furnace characterized by heating a workpiece in the work space from the work space side. The opening part which is equipped with opening and shutting doors in the front and back of the room and carries the workpiece in and out of the room wall according to claim 16; the inside of the opening is a tunnel shape, and convection heat is introduced from the bottom part to the center part and the bottom part of the ceiling A structure having an opening to be discharged from the upper part; a radiant heat medium wall in which both vertical sides of the structure receive heat energy and a heat radiating surface; function as a tray for carrying workpieces in the lower part of the chamber and a frame A set of roll parts constituting a roller-type conveying device provided; on the ceiling of the room, a fan for circulating a heating medium inert gas connected to a rotary electric motor placed outdoors; a rectifying part at the bottom of the room, heating A heating source that generates energy, and a high-purity inert gas introduction pipe to the indoor heating energy generation chamber and an inert atmosphere gas exhaust pipe to the outside,
Work space enclosed by the inner wall of the structure and a set of rolls; located at the lower part of the radiant heat medium wall from the left and right upper spaces partitioned by the upper and side surfaces of the outer wall of the structure and the inner wall of the furnace A heating energy generation chamber / heating energy circulation circuit in a space up to the position of a set of roll portions to be heated; a heating energy introduction chamber surrounded by the heating energy generation chamber / heating energy circulation circuit and the bottom of the room and a set of roll portions; An introduction hole for sending heating energy to the working space is formed in the gap between a set of roll parts,
The heating medium inert gas is adjusted to the specified temperature, dew point temperature, and oxygen concentration with the heat energy produced by the heating source provided in the heating energy generation chamber and the high purity inert gas introduced from the introduction pipe into the generation chamber. Then, it is sent to the heating energy introduction chamber through the heating energy circulation circuit by the circulation fan, receives the flow adjustment at the rectifying part, and flows into the working space from the introduction hole constituted by the opening of the pair of roll parts. The workpiece is heated as convection heat and circulated again from the upper opening of the work space to the heating energy generation chamber. On the other hand, by heating the side of the heating energy circuit of the radiant heat medium wall, the radiant heat medium wall becomes radiant heat, A convection and radiant heat combined brazing furnace characterized by heating a workpiece in the work space from the work space side. The furnace applied to claim 1, wherein the intermediate process chamber is connected between the temperature raising process chamber and the brazing process chamber.

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