TWI859644B - Welding quality controlling method, welding bed and molten welding system - Google Patents

Abstract

A welding quality controlling method is adapted for solving the conventional problem prone to generating the intermetallic compound within the welding line while cooling. The method comprises the following steps. A first workpiece and a second workpiece are provided, and the edges of the first and second workpieces to be welded contact to each other. The to-be-welded welding line is formed a wleded zone within temporary molten state. The wleded zone has at least two metallic phases changing by a relationship with temperature and time in the cooling process. One of the at least two metallic phases generates the intermetallic compound. A predetermined temperatur controlling condition within a specifice time period is defined by a corresponding time-temperature-transformation diagram, thereby controlling the temperature-time relationship of the wleded zone, so that the time period undergoing the metallic phase generating the intermetallic compound in the cooling process can be minimized.

Description

Method for controlling welding quality, welding platform and fusion bonding system

The present invention relates to a processing method, in particular to a method for controlling welding quality, a welding platform and a fusion bonding system.

Laser welding uses a high-energy-density light source to irradiate the material, so that the material absorbs the laser energy and generates heat energy to melt or even vaporize to form a molten pool, and then cools the object to join. However, in the known technology, when laser welding is used to try to join two dissimilar metals, intermetallic compounds (Intermetallic Compound) will be easily generated at the welding junction of the two dissimilar metals. In particular, the intermetallic compound is easy to produce a hard and brittle phase structure during the natural cooling process, making the corresponding weld line (Welding Line)/welding joint (Welding Joint) easy to brittle, making the welded junction between the dissimilar metals unable to be effectively joined.

In view of this, the conventional welding channel cooling method still needs to be improved.

In order to solve the above problems, the purpose of the present invention is to provide a method for controlling welding quality, which can improve the quality of welding track connection.

The second purpose of the present invention is to provide a welding platform that can facilitate the control of the temperature of the target area, thereby improving the quality of the welding track.

A second object of the present invention is to provide a fusion bonding system that can improve the quality of weld bonding.

The directions or similar terms described in the present invention, such as "front", "rear", "left", "right", "upper", "lower", "inner", "outer", "side", etc., are mainly for reference to the directions of the attached drawings. Each direction or similar terms are only used to assist in the description and understanding of the various embodiments of the present invention, and are not used to limit the present invention.

The quantifiers "one" or "a" used in the components and parts described throughout the present invention are only for the convenience of use and to provide a general meaning of the scope of the present invention; in the present invention, they should be interpreted as including one or at least one, and the single concept also includes the plural case, unless it is obvious that it means otherwise.

The similar terms such as "combination", "assembly", "assembly" or "setting" mentioned in the present invention mainly include the connection that can be separated without damaging the components, or the connection that makes the components inseparable, which can be selected by those with ordinary knowledge in the field according to the materials of the components to be connected or the assembly requirements.

The term "coupling" used throughout this invention includes direct or indirect electrical and/or signal connections, which can be selected by those with ordinary knowledge in the field according to usage requirements.

The "controller" mentioned in the whole text of the present invention may include at least one "processor", which refers to various data processing devices with specific functions and implemented by hardware or hardware and software to process and analyze information and/or generate corresponding control information, such as: electronic controllers, servers, cloud platforms, virtual machines, desktop computers, laptops, tablet computers or smart phones, etc., which can be understood by those with ordinary knowledge in the technical field to which the present invention/creation belongs. In addition, it may include a corresponding data receiving or transmitting unit to receive or transmit the required data. In addition, it may include a corresponding database/storage unit to store the required data. In particular, unless otherwise specifically excluded or contradictory, the processor may be a collection of multiple processors based on a distributed system architecture, used to include/represent the process, mechanism and result of information stream processing between multiple processors. In addition, the "controller" referred to in the present invention may represent an integrated technical feature, which may be a single controller coupled and integrated to control one or more coupled devices, or multiple controllers separately control the coupled devices, etc., so that the corresponding device performs its function under appropriate conditions.

The "weld path" mentioned in the full text of the present invention includes the predetermined welding point/path of the two workpieces before welding, the molten pool formed during welding, and the area formed during the cooling process of the molten pool. In addition, the predetermined welding point corresponds to the "weld path to be welded" mentioned in the full text of the present invention; the molten pool formed during welding corresponds to the "weld junction and (temporarily) having a corresponding molten state" mentioned in the full text of the present invention; and the area formed during the cooling process of the molten pool corresponds to the "weld junction" mentioned in the full text of the present invention. In addition, the "cooling process" described in the entire text of the present invention refers to the process of changing the welded interface/weld track in a molten state into a welded interface/weld track in a stable solidified state.

The method for controlling welding quality of the present invention comprises: providing a first workpiece and a second workpiece, making the interface between the first workpiece and the second workpiece to be welded abut each other to define a weld path to be welded; the first workpiece is made of a first material, the second workpiece is made of a second material, the first material and the second material are a metal or an alloy, and the first material and the second material have different constituent elements and/or different proportions of constituent elements; forming a weld interface having a corresponding molten state for the weld path to be welded, and forming a weld interface at the molten state; The welded joint has the molten components of all or part of the elements of the first material and the second material; the welded joint in the molten state has at least two metal phases changing with the relationship between temperature and time during the cooling process, and one of the at least two metal phases will produce intermetallic compounds, and the other of the at least two metal phases will not produce intermetallic compounds, and the preset temperature control conditions within a certain period of time are defined according to the corresponding time-temperature deformation diagram to control the corresponding temperature with time, so as to minimize the time of the metal phase that will produce intermetallic compounds during the cooling process.

The welding platform of the present invention is configured to implement the method of controlling welding quality as described in the present invention. The welding platform comprises: a platform body having a top surface and a bottom surface opposite to the top surface; a platform cooling structure having at least one air inlet channel and a plurality of air outlet channels; the air inlet channel is arranged inside the platform body and has an air inlet for a gas to pass into the air inlet channel; the air outlet channel is connected to the air inlet channel and has an air outlet arranged in a direction away from the bottom surface of the platform body; and a platform heater is arranged adjacent to the top surface of the platform body.

The fusion bonding system of the present invention comprises: a fusion energy supplier, used to make the irradiated area of the corresponding metal workpiece form a molten state; such as the welding platform of the present invention, the fusion energy supplier and the welding platform can generate relative movement according to a predetermined processing path; a cooling gas supplier, used to supply a cooling gas to the air inlet channel of the platform cooling structure; a temperature sensor, which is arranged in the platform body and adjacent to the top surface; and a controller, which is respectively connected to the fusion energy supplier and the controller. The supply, the cooling gas supply, the platform heater and the temperature sensor are coupled to: control the power of the melting energy supply to perform laser welding on the target area; and receive the temperature sensed by the temperature sensor, and adjust the flow rate of the gas supplied by the cooling gas supply to the gas channel according to the temperature and time relationship in a target processing temperature to cool the target area; and/or adjust the output power of the platform heater to heat up or maintain a certain temperature in the target area.

Accordingly, the method for controlling welding quality, welding platform and fusion bonding system of the present invention can achieve the effect of reducing or avoiding the generation of intermetallic compounds by performing temperature control with corresponding preset temperature control conditions, thereby achieving the effect of improving the stability and quality of the weld. In addition, the welding platform has a corresponding platform cooling structure and platform heater, which can achieve the effect of facilitating the instantaneous corresponding temperature control of the weld (through the weld junction), especially by performing temperature control with preset temperature control conditions, which can achieve the effect of improving the stability and quality of the weld. In addition, by coupling the controller in the fusion bonding system with various devices (especially the temperature sensor, the cooling gas supplier and the platform heater), the corresponding temperature control of the weld can be achieved in real time, thereby achieving the effect of improving the stability and quality of the weld.

The temperature control method includes applying cooling gas to the welding junction to reduce the temperature of the welding junction. In this way, the effect of controlling the welding quality can be achieved by applying cooling gas.

The temperature control method includes contacting the first workpiece and the second workpiece through a heat dissipation fixture, and the heat dissipation fixture has at least one of a thermal conductivity of more than 40W/m‧K, a heat dissipation fin, and a liquid cooling channel for circulating cooling liquid. In this way, through the corresponding technical features of the heat dissipation fixture, the effect of enhancing the heat dissipation efficiency of the workpiece can be achieved, thereby achieving the effect of faster cooling of the weld.

The temperature control method includes providing heat energy to the welded junction to increase or maintain the temperature of the welded junction at a specific temperature. In this way, by providing heat energy to the weld, the effect of controlling the welding quality can be achieved.

The period of time is 1 hour to 100 hours. Thus, by controlling the temperature during the period of time, the components in the weld can form a stable structure, thereby improving the stability and quality of the weld.

The first material includes aluminum, the second material includes copper, and the certain period of time is 1 to 100 hours; after the welded junction is molten, the temperature of the welded junction is reduced to below 200°C within 1 to 36 seconds; and then heat energy is provided to the welded junction to maintain the temperature of the welded junction at 140 to 200°C until the end of the certain period of time. In this way, the generation of intermetallic compounds between aluminum and copper can be reduced or avoided through the cooling conditions; and the temperature maintenance conditions can form a more stable structural form of the weld between aluminum and copper, thereby achieving the effect of improving the stability and quality of the weld.

The top surface has a concave portion which is concave from the top surface, and the concave portion extends in a direction to form a long strip-shaped concave space; the concave portion has a concave surface located between the top surface and the bottom surface; the air inlet channel is located below the concave portion and extends along the concave portion; the air outlet is formed on the concave surface; and the platform heater is arranged at a position corresponding to the concave portion. Thus, by providing the recessed portion, when the weld in the molten state has a portion partially protruding toward the top surface of the platform body, a suitable accommodation space can be provided to prevent the weld and the welding platform from being combined due to high heat, thereby protecting the weld and preventing the welding platform from being damaged. In addition, the structure of the recessed portion helps the cooling gas to flow in the corresponding recessed space, thereby achieving The effect of faster heat dissipation and cooling is achieved. In addition, the configuration of the recessed portion of the platform heater can help the platform heater to be located below the weld to be maintained at a temperature, so that the weld temperature can be maintained more efficiently. In addition, the structure of the recessed portion can also help heat convection to form in the recessed portion, so that the weld can be heated more evenly, thereby achieving the effect of improving the stability and quality of the weld.

The platform heater has a protrusion that protrudes from the concave surface of the concave portion and does not exceed a plane defined by the top surface of the platform body. Thus, the configuration of the protrusion helps the platform heater to be closer to the weld and not interfere with the weld, so as to achieve the effect of maintaining the weld temperature more efficiently.

1: Melting energy supplier

1G: Protective gas supply

1N: Air nozzle

2: Welding platform

20: Platform body

20a: Top surface

20b: Bottom surface

20c: Depression

20d: Concave surface

3: Platform cooling structure

3G: Cooling gas supply

30: Air intake duct

30I: Air intake

31: Exhaust channel

31E: Air outlet

4: Platform heater

4P: protrusion

5: Temperature sensor

6: Heat dissipation fixture

61: Fins

62: Liquid cooling channel

AS2: Optional step

C: Controller

Ln: Temperature change line segment of natural cooling

Lp: An example line segment of the default temperature control condition

_PIC : Intermetallic Compound Formation Phase

_PSS : Supersaturation phase

P _S : Stable phase

S1, S2, S3: Steps

W1: First workpiece

W2: Second workpiece

[Figure 1] A partial perspective view of a preferred embodiment of the fusion bonding system of the present invention.

[Figure 2] A partial front view of the usage as shown in Figure 1.

[Figure 3] Sectional view along line A-A of Figure 2.

[Figure 4] A better flow chart of the method for controlling welding quality of the present invention.

[Figure 5] A side view of a preferred embodiment of the heat dissipation fixture of the present invention.

[Figure 6] Temperature transformation diagram of aluminum and copper metals.

In order to make the above and other purposes, features and advantages of the present invention more clearly understood, the following specifically cites the preferred embodiments of the present invention and provides a detailed description in conjunction with the attached drawings; in addition, the same symbols in different drawings are considered the same and their descriptions will be omitted.

Please refer to Figures 1 and 2, which are a preferred embodiment of the fusion bonding system of the present invention, including a fusion energy supplier 1, a welding platform 2 and a controller C. The controller C is coupled to the fusion energy supplier 1 and the welding platform 2 respectively; the fusion energy supplier 1 and the welding platform 2 can generate relative motion according to a predetermined processing path, and the components or mechanisms used to generate the relevant motion are understandable to those with common knowledge in the field, and the detailed structure and principle are not repeated in the present invention.

In order to conveniently display a preferred embodiment of the present invention, the melting energy supplier 1 is presented in the form of a laser beam supplier in the drawings of the present invention. However, it should be noted that the melting energy supplier 1 is used to supply melting energy to melt-join the interface of two metal workpieces, especially to form molten metal in the irradiated area of the corresponding metal workpiece through the supplied melting energy, so that the two metal workpieces are joined through the corresponding molten metal area; therefore, the melting energy supplier 1 is not limited to a laser beam supplier. In particular, the method of the fusion type joining may be, for example, arc welding, laser welding, electron welding or resistance welding, and the fusion energy may be correspondingly an arc, a laser beam, an electron beam, or thermal energy, and the fusion energy supplier 1 may be correspondingly an arc energy supplier, a laser beam supplier, an electron beam supplier, or a thermal energy supplier. In addition, the above-mentioned technology of using fusion energy for fusion type joining is understandable to those with ordinary knowledge in the field, and therefore, the detailed structure and principle of the fusion energy supplier 1 will not be described in detail in the present invention.

Preferably, the melting energy supplier 1 has a protective gas ejection device, which has a protective gas supplier 1G and a gas nozzle 1N, and is used for supplying protective gas to the gas nozzle 1N from the protective gas supplier 1G when the melting energy supplier 1 emits melting energy to perform melting type joining on a target area of a target object, so that the gas nozzle 1N synchronously ejects protective gas at the welding position, so as to avoid the situation where oxides are generated at the melting type joining position of the target area. Among them, the protective gas ejection device (protective gas supply device 1G and the gas nozzle 1N) is also understandable to those with ordinary knowledge in the field, and its detailed structure and principle are not repeated in the present invention. The protective gas may be composed of argon, helium, or a mixture of argon and helium, which can protect the weld from oxide formation during the welding process and provide air cooling during the cooling process.

The welding platform 2 includes a platform body 20, a platform cooling structure 3 and a platform heater 4, and preferably further includes at least one temperature sensor 5. The platform body 20 has a top surface 20a and a bottom surface 20b opposite to the top surface 20a, and the top surface 20a faces the melting energy supplier 1. Preferably, the top surface 20a has a recessed portion 20c recessed from the top surface 20a to define a recessed space; in particular, the recessed portion 20c can extend in a direction to form a long strip of recessed space. More preferably, the recessed portion 20c has a recessed surface 20d, and the recessed surface 20d is located between the top surface 20a and the bottom surface 20b. Preferably, the platform body 20 is selected from a high thermal conductivity material, preferably having a thermal conductivity of 40W/m·K or more, for example, it can be made of copper or copper alloy.

In addition to referring to FIGS. 1 and 2, please also refer to FIG. 3, where the platform cooling structure 3 is disposed on the platform body 20, and has at least one air inlet channel 30 and a plurality of air outlet channels 31. The air inlet channel 30 is disposed inside the platform body 20, and has an air inlet 30I for allowing a gas to enter the air inlet channel 30; preferably, the air inlet channel 30 is located below the recessed portion 20c and extends along the recessed portion 20c, and in particular, can be located between the recessed portion 20 and the bottom surface 20b of the platform body 20. The outlet channel 31 is connected to the inlet channel 30 and has an outlet 31E disposed in a direction away from the bottom surface 20b of the platform body 20; thereby, when a gas enters the inlet channel 30 from the inlet 30I, the gas will be discharged from the outlet 31E of the outlet channel 31, especially in a direction away from the bottom surface 20b. Preferably, the outlet 31E is disposed in the recessed portion 20c, and more preferably formed in the recessed surface 20d.

Preferably, the outlet channel 31 forms a gradual channel from the connection with the inlet channel 30 toward the outlet port 31E; in particular, the connecting end 31a of the outlet channel 31 connected to and communicated with the inlet channel 30 has a larger channel area, and the outlet port 31E has a smaller channel area, so that the outlet channel 31 forms the gradual channel. The configuration of the gradual channel helps to make the airflow ejected from the outlet port 31E have a higher flow rate, and then when the high-flow gas is sprayed on the target area to be cooled (such as the first workpiece W1 and the second workpiece W2 in Figure 2), the corresponding heat dissipation speed/efficiency can be improved.

In addition, the fusion bonding system of the present invention also has a cooling gas supply device 3G, which is used to supply the corresponding cooling gas to the platform cooling structure 3. In detail, the cooling gas supply device 3G can have a corresponding valve and a communication pipe; the communication pipe is connected between the cooling gas supply device 3G and the air inlet channel 30, and the valve can control the size of the cooling gas flow. In this way, the cooling gas supply device 3G can supply cooling gas to the air inlet channel 30 of the platform cooling structure 3, and then the multiple air outlets 31E spray cooling gas. The composition of the cooling gas may include the protective gas or atmosphere, and the gas may be at room temperature, especially not higher than 100°C, and may be passed into the welding platform 2 for cooling; preferably, the temperature of the cooling gas may be not higher than 25°C.

Please refer to FIGS. 1 and 2. The platform heater 4 is a resistive heater (as shown in FIG. 3), an induction coil heater (not shown) or other heaters. It should be noted that the implementation of the heater is understandable to those with ordinary knowledge in the field, and the present invention is not limited to the examples. The platform heater 4 is disposed in the platform body 20; in particular, it is disposed in whole or in part in the platform body 20 and disposed adjacent to the top surface 20a to form a heat source so that the temperature of the target area (such as the first workpiece W1 and the second workpiece W2 in FIG. 4) adjacent to the top surface 20a can be increased. Preferably, the platform heater 4 is disposed at a position corresponding to the recessed portion 20c to heat the portion of the target area adjacent to the recessed portion 20c. More preferably, the platform heater 4 may have a protrusion 4P protruding from the concave surface 20d of the concave portion 20c and not exceeding a plane defined by the top surface 20a of the platform body 20; thus, the protrusion 4P of the platform heater 4 can be closer to the target area to be heated, so as to improve the corresponding heating efficiency.

Please refer to FIG. 1 , the temperature sensor 5 can be used to sense the temperature of its vicinity, and in order to more accurately obtain the temperature distribution of the corresponding observation object at a specific position (for example, along the welded weld), it is better to evenly configure a plurality of the temperature sensors 5 along the position to be observed (the welded weld) to monitor the temperature distribution of the entire observation area (the welded area, especially the weld). The relevant implementation method and specific device are understandable to those with ordinary knowledge in the technical field of the present invention, so they are not repeated here; optionally, in order to enable the welding platform 2 of the present invention to be assembled more tightly, the temperature sensor 5 can be a sheet, flat or patch sensor. In detail, the temperature sensor 5 is disposed in the platform body 20 and adjacent to the top surface 20a, so as to sense the temperature of the adjacent target area, especially the temperature of the target area after being acted upon by the platform cooling structure 3 or the platform heater 4. Preferably, the temperature sensor 5 is disposed adjacent to the recess 20c; or optionally disposed in the recess 20c (not shown).

The controller C can be coupled to the cooling gas supplier 3G, the platform heater 4 and the temperature sensor 5 respectively to receive the temperature sensed by the temperature sensor 5, and adjust the flow rate of the gas supplied by the cooling gas supplier 3G to the gas channel 30 according to the temperature and time relationship in a target processing temperature to cool the target area; or adjust the output power of the platform heater 4 to heat up the target area or maintain a certain temperature. In particular, the controller C can also be coupled to the melting energy supplier 1 and the corresponding protective gas supplier 1G to control the power of the melting energy supplier 1 to perform melting type joining on the target area, and control the protective gas supplier 1G to control the flow rate of the protective gas sprayed by the gas nozzle 1N.

Please refer to Figures 2 and 4. Based on the above configuration, the usage and corresponding processing method of the fusion bonding system of the present invention can be described as follows.

Step S1: Provide a first workpiece W1 and a second workpiece W2, so that the junction of the first workpiece W1 and the second workpiece W2 to be welded is abutted against each other to define a weld path to be welded. The first workpiece W1 is made of a first material, and the second workpiece W2 is made of a second material. Preferably, the first workpiece W1 and the second workpiece W2 are respectively composed of the first material and the second material. The first material and the second material are a metal or an alloy, and the first material and the second material have different constituent elements (in the form of two heterogeneous metals) and/or different proportions of constituent elements (in the form of a metal and an alloy, or in the form of two alloys), so that the molten state formed at the junction of the first workpiece W1 and the second workpiece W2 has a third material of at least two metal elements, and the composition and proportion of the constituent elements in the third material are different from those of the first material and the second material.

In detail, the first workpiece W1 and the second workpiece W2 are fixed to the top surface 20a of the welding platform 2, especially so that the weld to be welded is aligned above the recessed portion 20C. At this time, the melting energy supplier 1 and the optional air nozzle 1N are preferably controlled by the controller C to be aligned to a part of the weld to be welded.

The fixing method of the first workpiece W1 and the second workpiece W2 is to use a corresponding heat dissipation fixture 6 to prevent the first workpiece W1 and the second workpiece W2 from being offset due to thermal stress or material deformation generated during welding. Optionally, the heat dissipation fixture 6 is at least arranged on one side of the first workpiece W1 and the second workpiece W2, so that the first workpiece W1 and the second workpiece W2 are fixed between the platform body 20 and the heat dissipation fixture 6; however, the method of fixing the workpiece by the heat dissipation fixture 6 is not limited to the above.

Preferably, as shown in FIG. 5 , the heat sink fixture 6 has a plurality of fins 61 to improve the heat dissipation efficiency of the heat sink fixture 6. Preferably, the heat sink fixture 6 has a liquid cooling channel 62 for the corresponding cooling liquid to pass through to improve the heat dissipation efficiency of the heat sink fixture 6. Corresponding to the liquid cooling channel 62, there may be a cooling liquid supplier and a corresponding pipeline (not shown) to provide cooling liquid to pass through the liquid cooling channel 62. Optionally, the cooling liquid supplier is also coupled to the controller C so that the controller C controls the output of the cooling liquid in the cooling liquid supplier. Preferably, the heat sink fixture 6 is selected from a high thermal conductivity material, preferably having a thermal conductivity of 40W/m‧K or more, for example, it may be made of copper or copper alloy.

Step S2: The weld track to be welded is formed into a welded junction temporarily having a corresponding molten state. In detail, melting energy is applied to the weld track to be welded, so that the position where the melting energy is applied forms a welded junction temporarily having a corresponding molten state. The molten state can also be called a molten pool (Welding Pool/Molten Pool). The welded junction in the molten state has molten components of all or part of the elements of the first material and the second material. In one example, the molten state corresponds to a complete melting temperature, and the complete melting temperature is higher than the melting points of at least two metal elements; at this time, all elements of the first material and the second material are in a molten state, and a bond is formed in the molten state. In another example, the molten state corresponds to a local melting temperature, which is between the melting points of two metal elements; at this time, a metal element with a melting point lower than the local melting temperature forms a molten state and diffuses to another metal (melting point higher than the local melting temperature) through the diffusion characteristics of the metal at high temperature to form a bond.

Specifically, the present invention is particularly concerned with the fact that the welded interface/weld channel in a molten state (including the composition of the molten pool and/or the vicinity of the molten pool (having the above-mentioned diffusion characteristics of the metal at high temperature)) has at least two metal phases (Metallic Phase), and one of the at least two metal phases will produce intermetallic compounds, and the other of the at least two metal phases will not produce intermetallic compounds, and the preset temperature control conditions within a certain period of time are defined according to the corresponding time-temperature deformation diagram (as shown in Figure 6) to control the corresponding temperature level with time, so as to minimize the time of the metal phase that will produce intermetallic compounds during the cooling process, so as to reduce or avoid the generation of intermetallic compounds in the molten state during the cooling process. In detail, the phenomenon of having at least two metal phases with the relationship between temperature and time is related to the ratio of at least two metal elements contained in the corresponding molten components, and with the change of processing temperature and time, in different metal phases, different elements have corresponding changes in structure and composition. Preferably, the present invention can be applied to welding between various heterogeneous metals such as aluminum-copper metals and aluminum-iron metals. It should be noted that the preset temperature control conditions corresponding to different metal components (including different component ratios) are also different.

As shown in FIG. 6, the first material of the first workpiece W1 is aluminum metal (alloy number 1xxx aluminum alloy), and the second material of the second workpiece W2 is copper metal (alloy number C1100 copper alloy), and the corresponding time-temperature transformation diagram (TTT Diagram)/isothermal transformation diagram (IT Diagram) are shown. FIG. 6 shows that the two heterogeneous metals containing aluminum and copper have three metal phase changes in the molten state (especially near the aluminum metal side) with the relationship between temperature and time, namely, supersaturated phase (Supersaturated Phase) P _SS , stable phase (Stable Phase) P _S and intermetallic compound formation phase P _IC . The intermetallic compound phase P _IC is a saturated phase that precipitates with the intermetallic compound copper (CuAl2), that is, the intermetallic compound phase P _IC is a metal phase that will produce intermetallic compounds. Therefore, if the generation of intermetallic compounds is to be reduced or avoided, the corresponding temperature control must be performed over time during a subsequent period of time to reduce or avoid the metal phase at the welding interface meeting the conditions corresponding to the intermetallic compound phase P _IC .

As shown in Figure 6, line segment Ln shows an example of the temperature change corresponding to the natural cooling of the molten pool under a standard state (roughly room temperature 25°C, atmospheric pressure); line segment Lp shows an example of the preset temperature control condition. It can be seen from the line segment Ln and the line segment Lp that during the natural cooling process (i.e., the line segment Ln), the line segment Ln undergoes a longer time for the intermetallic compound formation phase _PIC , and more intermetallic compounds (aluminum-copper) will be produced. However, since the aluminum-copper intermetallic compound has high brittleness, it will lead to easy fracture at the welding junction, which is a situation to be avoided in the present invention. In the temperature control process through the preset temperature control condition (i.e., the line segment Lp), high-speed cooling is first performed to avoid the metal phase that will produce the precipitation of intermetallic compounds, and then a certain temperature is maintained for a certain period of time so that the welded interface has a better metal phase (i.e., the metal phase that will produce the precipitation of intermetallic compounds is completely avoided, and the time of experiencing the metal phase that will produce intermetallic compounds during the cooling process is minimized (the corresponding time in this example is 0)).

Optional step AS2: applying a protective gas when the weld track to be welded forms a corresponding molten state at the welded junction. In detail, while applying melting energy to the weld track to be welded, a protective gas can be applied to the weld track to be welded where the melting energy is applied to prevent the corresponding molten metal from forming unexpected oxides during the solidification process. The above-mentioned method of applying gas can be realized by controlling the nozzle 1N to spray the corresponding protective gas on the upper side of the workpieces W1 and W2 (the side of the workpiece facing the melting energy supplier 1), or by spraying the corresponding cooling gas and the lower side of the workpieces W1 and W2 (the side of the workpiece facing the top surface 20a) through the gas outlet 31E, or by spraying the corresponding gas through the nozzle 1N and the gas outlet 31E at the same time. Preferably, an additional fixed nozzle (not shown) can be set on the side of the top surface 20a to continuously apply the corresponding gas to the welded junction on the upper side of the workpieces W1 and W2 to reduce or avoid the generation of oxides, and have a cooling effect.

Step S3: According to the preset temperature control condition corresponding to the composition of the molten state contained in the welded junction, the temperature of the welded junction is controlled to minimize the time of the metal phase that will produce intermetallic compounds during the cooling process, so that the generation of intermetallic compounds can be reduced or avoided at the welded junction; optionally, after completing the above temperature control, the temperature is reduced to below 100°C to form a temperature-controlled weld. In particular, the preset temperature control condition is defined according to the time-temperature deformation diagram of the composition of the molten state contained in the welded junction, so as to adjust the temperature of the welded junction within a certain period of time according to the corresponding time-temperature deformation diagram to avoid the generation of metal transformation phases that will produce intermetallic compounds. The certain period of time is from 1 hour to 100 hours, and the corresponding time length adjustment can be adjusted in intervals of 0.1 seconds.

When the temperature of the welded junction needs to be lowered, the controller C can be used to control the air outlet 31E to spray cooling gas to the welded junction; in particular, the controller C controls the corresponding cooling gas supplier 3G to pass cooling gas to the air inlet channel 30, so that the cooling gas is sprayed from the air outlet 31E; in this way, the temperature of the welded junction can meet the preset temperature control conditions within a certain period of time. Preferably, in order to improve the cooling of the welded junction, the heat dissipation fixture 6 can also have a high thermal conductivity, or have a corresponding heat dissipation fin 61, or have a liquid cooling channel 62 for the cooling liquid to pass through, so as to improve the heat dissipation efficiency of the welded junction, thereby improving the cooling efficiency.

When the temperature of the welded junction needs to be increased, heat energy is provided to the welded junction to increase the temperature of the welded junction or maintain it at a specific temperature, so that the temperature of the welded junction meets the preset temperature control conditions within a certain period of time. In detail, the temperature of the welded junction can be increased by controlling the platform heater 4 of the controller C.

Preferably, the controller C controls the above cooling method and/or heating method to cool down and/or heat up the welded junction according to the temperature sensed by the temperature sensor 5 and the preset temperature control conditions corresponding to the current metal components, so that the temperature of the welded junction meets the preset temperature control conditions within a certain period of time.

For example, the first workpiece W1 is aluminum metal, and the second workpiece W2 is copper metal, and based on the temperature transformation diagram of aluminum and copper in Figure 6, the controller C can be controlled to spray cooling gas from the air outlet 31E to the welded interface, and preferably the controller C can be controlled to allow cooling liquid to pass through the liquid cooling channel 62 of the heat dissipation fixture 6, so that the temperature change at the welded interface over time does not meet or only meets the temperature change range of the corresponding intermetallic compound generation phase _PIC over time within a certain period of time for a short duration; the short duration is, for example, several seconds, preferably not more than 5 seconds. In addition, optionally, in order to make the welded junction have better characteristics, the controller C can control the platform heater 4 to heat the welded junction so that the temperature change of the welded junction over time, for a duration within a certain period of time, meets the corresponding stable phase P _S temperature change range over time; the duration can be, for example, more than 0.5 hours.

Based on FIG. 6, in a preferred example, the certain period of time is 1 to 100 hours. After the welded portion forms a molten state at the welded junction, the temperature of the corresponding welded junction is immediately reduced to below 200°C (preferably below 150°C) within 1 to 36 seconds; and then heat energy is provided to the welded junction to maintain the temperature of the welded junction at 140 to 200°C until the certain period of time ends. In detail, by reducing the temperature to 200°C within 36 seconds, the formation of intermetallic _compounds can be avoided. In addition, by maintaining the temperature at 140~200℃ for 1~100 hours, the welded interface can be in the stable phase Ps or supersaturated phase P _SS . In this way, the metallographic phase of the welded interface obtained by the above method has a tighter welding bond, less intermetallic compound generation, and fewer and smaller pores than that obtained by the natural cooling method, which greatly improves the welding strength and stability between the dissimilar metals of aluminum and copper.

It should be noted that in order to make the temperature sensed by the temperature sensor 5 close to the temperature of the welded junction, the corresponding sensed temperature can be compensated according to at least one of the factors such as the position of the temperature sensor 5, its distance from the welded junction, the material of the workpiece and the material of the welding platform, so as to be close to the actual temperature of the welded junction, and the quality of the weld can be more accurately controlled.

It should be noted that the welding platform 2 proposed in the present invention can be applied to various welding methods, and in particular can be applied to temperature control (cooling and/or heating) at the welding interface.

In summary, the method for controlling welding quality, welding platform and fusion bonding system of the present invention can reduce or avoid the generation of intermetallic compounds through the corresponding preset temperature control conditions for the metal phases that will generate intermetallic compounds during the change of the metal phase at the welding interface. In addition, the welding platform has a corresponding platform cooling structure and platform heater, which can be applied to the temperature control of the welding interface. In addition, the platform body has a higher thermal conductivity, which can facilitate the rapid adjustment of the temperature of the workpiece above the platform body. In addition, through the configuration of the temperature sensor, the workpiece temperature can be sensed in real time, especially the temperature of the welding processing area, which can be used as a basis for temperature control and adjustment.

Although the present invention has been disclosed using the above preferred embodiments, they are not intended to limit the present invention. Any person skilled in the art can make various changes and modifications to the above embodiments within the spirit and scope of the present invention. These changes and modifications are still within the technical scope protected by the present invention. Therefore, the protection scope of the present invention includes all changes within the meaning and equivalent scope recorded in the attached patent application scope. In addition, when the above several embodiments can be combined, the present invention includes any combination of implementations.

1: Melting energy supplier

1N: Air nozzle

2: Welding platform

20: Platform body

20a: Top

20b: Bottom surface

20c: Depression

20d: Concave surface

3: Platform cooling structure

30: Air intake duct

30I: Air intake

31: Exhaust channel

31E: Air outlet

4: Platform heater

4P: protrusion

5: Temperature sensor

6: Heat dissipation fixture

W1: First workpiece

W2: Second workpiece

Claims (10)

A method for controlling welding quality comprises: providing a first workpiece and a second workpiece, making the junction of the first workpiece and the second workpiece to be welded abut each other to define a weld path to be welded; the first workpiece is made of a first material, and the second workpiece is made of a second material, the first material and the second material are a metal or an alloy, and the first material and the second material have different constituent elements and/or different proportions of constituent elements; making the weld path to be welded form a welded junction temporarily having a corresponding molten state, and the welded junction in the molten state has a molten component of all elements or partial elements of the first material and the second material. ; The welded junction in the molten state has at least two metal phase changes in the relationship between temperature and time during the cooling process, and one of the at least two metal phases will produce intermetallic compounds, and the other of the at least two metal phases will not produce intermetallic compounds, and the preset temperature control conditions within a certain period of time are defined according to the corresponding time-temperature deformation diagram to control the corresponding temperature with time, so as to minimize the time of the metal phase that will produce intermetallic compounds during the cooling process; and the welded junction is temperature controlled within a certain period of time according to the preset temperature control conditions corresponding to the molten components contained in the welded junction in the molten state. A method for controlling welding quality as claimed in claim 1, wherein the temperature control method includes applying cooling gas to the welding junction to reduce the temperature of the welding junction. A method for controlling welding quality as claimed in claim 1, wherein the temperature control method includes contacting the first workpiece and the second workpiece through a heat sink, and the heat sink has at least one of a thermal conductivity of 40 W/m‧K or more, a heat sink fin, and a liquid cooling channel for circulating cooling liquid. A method for controlling welding quality as claimed in claim 1, wherein the temperature control method includes providing heat energy to the welded junction to increase the temperature of the welded junction or maintain it at a specific temperature. A method for controlling welding quality as in any one of claims 1 to 4, wherein the certain period of time is 1 to 100 hours. A method for controlling welding quality as claimed in any one of claims 1 to 4, wherein the first material comprises aluminum, the second material comprises copper, and the certain period of time is 1 to 100 hours; after the welded joint is formed into a molten state, the temperature of the welded joint is reduced to below 200°C within 1 to 36 seconds; and heat energy is provided to the welded joint so that the temperature of the welded joint is maintained at 140 to 200°C until the end of the certain period of time. A welding platform, configured to implement a method for controlling welding quality as in any one of claims 1 to 6, the welding platform comprising: a platform body, having a top surface and a bottom surface opposite to the top surface; a platform cooling structure, having at least one air inlet channel and a plurality of air outlet channels; the air inlet channel is arranged inside the platform body, and has an air inlet for a gas to pass into the air inlet channel; the air outlet channel is connected to the air inlet channel, and has an air outlet arranged in a direction away from the bottom surface of the platform body; and a platform heater, which is arranged adjacent to the top surface of the platform body. As in claim 7, the welding platform, wherein the top surface has a recessed portion recessed from the top surface, and the recessed portion extends in a direction to form a long strip of recessed space; the recessed portion has a recessed surface located between the top surface and the bottom surface; the air inlet channel is located below the recessed portion and extends along the recessed portion; the air outlet is formed on the recessed surface; the platform heater is arranged at a position corresponding to the recessed portion. As in claim 8, the welding platform, wherein the platform heater has a protrusion protruding from the concave surface of the concave portion and does not exceed a plane defined by the top surface of the platform body. A melting type joining system comprises: a melting energy supplier for making the irradiated area of the corresponding metal workpiece form a molten state; a welding platform as in any one of claims 7 to 9, wherein the melting energy supplier and the welding platform can generate relative movement according to a predetermined processing path; a cooling gas supplier for supplying a cooling gas into the air inlet channel of the platform cooling structure; a temperature sensor disposed in the platform body and adjacent to the top surface; and a controller, respectively connected to the melting energy supplier and the welding platform; The melt energy supplier, the cooling gas supplier, the platform heater and the temperature sensor are coupled to: control the power of the melt energy supplier to perform melt-type bonding on the target area; and receive the temperature sensed by the temperature sensor, and adjust the flow rate of the gas supplied by the cooling gas supplier to the gas channel according to the temperature and time relationship in a target processing temperature to cool the target area; and/or adjust the output power of the platform heater to heat up the target area or maintain a certain temperature.

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