CN1317382A - Conticasting technology and equipment for producing thin-wall metal tube - Google Patents

Abstract

A process and equipment for producing thin-walled metal pipes by continuous casting, which uses the heat of molten metal to heat the inner core of the mold, and uses the heating body to heat the outer shape, so that the temperature of the inner core and the outer shape are kept at the casting temperature. It is above the melting point of the metal; and the combination of high liquid metal pressure and dummy rod and molten metal fusion makes the molten metal enter the narrow cavity. Therefore, there is no need to place a heating body in the inner core of the mold, and it can be used The molten metal enters the narrow cavity smoothly and freely, which can realize the production of thin-walled metal pipes with complex cross-sectional shapes and small sizes. In addition, the equipment used in the present invention has simple structure and high production efficiency.

Description

Process and equipment for producing thin-walled metal pipes by continuous casting

The invention relates to a process and equipment for producing thin-walled metal pipes by continuous casting, in particular to a process and equipment for producing thin-walled metal tubes with complex cross-sectional shapes by continuous casting.

The existing continuous casting method is to inject molten metal into a cooled mold, and after the metal forms a solidified shell, the solidified part is continuously pulled out, and the same amount of molten metal is injected into the drawn part at the same time. Since the solidification shell is attached to the mold wall, the friction force with the mold wall is very large, and the mold or casting must be vibrated to help the casting peel off from the mold. In addition, a lubricant must be added between the mold and the casting to reduce friction. This method cannot be used for tubular castings and thin-walled castings, because the strength and stiffness of thin-walled castings cannot withstand vibration and bending, and the linear shrinkage process that occurs immediately after solidification of tubular castings will form the inner core of the inner cavity of the tube Wrap tightly and cannot be unmoulded. Therefore, the existing continuous casting method can only cast solid billets or tube blanks with larger wall thickness.

Japanese patent clear 58-97463 proposes a kind of method that replaces the mold of cooling in the existing continuous casting with the mold of heating. In this process, both the shape forming the shape of the tube and the inner core forming the inner cavity of the tube are heated to above the solidification temperature of the metal by a heating element, so that the metal in the cavity formed by the shape and the inner core remains liquid, thereby eliminating the need for castings. Friction with outer shape and inner core. The metal in the cavity is drawn out with a dummy bar, and the dummy bar is cooled outside the mold, so as to realize continuous casting of tubular castings. US Patent No. 4,515,204 further clarifies that the pressure of the molten metal should be 0-0.002kg/cm ² to prevent the molten metal from leaking out during the continuous down-down casting of tubular castings.

Although these two patents provide a solution to the friction between the solidified metal shell and the outer shape and the inner core, there are still the following difficult problems in the continuous casting of thin-walled tubes with complex cross-sectional shapes:

1. For tubes with complex cross-sectional shapes commonly used in industry, the inner core has complex shapes and small sizes. It is difficult to realize that it is difficult to arrange the heating body in the inner core.

2. The pressure of the molten metal is too low, and it is difficult for the molten metal to enter the narrow cavity due to the hindrance of surface tension.

The object of the present invention is to overcome the above-mentioned shortcomings and provide a process for producing thin-walled metal pipes by continuous casting that does not need to install a heating body in the inner core of the mold and allows molten metal to enter the narrow cavity smoothly and freely.

Another object of the present invention is to provide a device for producing thin-walled metal pipes by continuous casting with simple structure, convenient and practical, and high production efficiency.

The present invention produces the technique of thin-walled metal pipe with continuous casting method, comprises the following steps:

1) Heat the outer shape of the mold with a heating body, and heat the inner core of the mold with the heat of molten metal, so that the temperature of the inner core and the outer shape are kept above the melting point of the cast metal;

2) Insert the dummy rod into the cavity so that its upper end is completely fused with the molten metal in the cavity. When the dummy rod is pulled down, the molten metal is brought into the narrow cavity, thereby casting a thin-walled tube with a complex cross-sectional shape;

3) Cool the dummy tube by spraying water from the cooler.

The present invention produces the equipment of thin-walled metal pipe by continuous casting method, and its structural representation is as shown in accompanying drawing 1, 2, comprises external shape (1), inner core (2), cooler (3), drawing roll ( 4), dummy rod (5), heating body (7), connecting pipe (8), crucible (9), liquid level control rod (10), wherein the inner core (2) is placed in the outer shape (1), Between the inner core (2) and the outer shape (1) is a cavity (1A), which is used to form the shape of a tube, and the molten pool (1B) is set above the outer shape (1), and is connected to the The crucible (9) is connected, the heating body (7) is placed outside the exterior (1), the liquid level control rod (10) is pressed into the crucible (9), and one end of the dummy rod (5) is inserted into the cavity (1A), The other end is exposed outside the mold cavity (1A), and the cooler (3) and the drawing roller (4) are placed on the exposed end of the dummy rod (5).

The specific situation of the present invention will be described in detail below in conjunction with the examples.

Fig. 1 is the structural representation of equipment used in the embodiment of the present invention;

Fig. 2 is a cross-sectional shape of a casting mold in an embodiment of the present invention.

Example:

The invention relates to a process and equipment for producing thin-walled copper pipes by continuous casting. Its process includes the following steps:

1) Heating the shape of the mold with a heating body, heating the inner core of the mold with the heat of molten metal, and keeping the temperature of the inner core and the shape above the melting point of the cast metal;

2) Insert the dummy rod into the cavity so that its upper end is completely fused with the molten metal in the cavity. When the dummy rod is pulled down, the molten metal is brought into the narrow cavity, thereby casting a thin-walled tube with a complex cross-sectional shape;

3) Cool the dummy tube by spraying water from the cooler.

In the above step 2), the dummy bar is pulled out downwards at a speed greater than 300mm/min.

The flow rate of water cooling in the above step 3) is 0.5-1.5 L/min, and the flow rate of water cooling in this embodiment is 1 L/min.

Its structure diagram of the equipment used in the present invention is as shown in Figure 1, comprises outer shape (1), inner core (2), cooler (3), drawing roll (4), dummy bar (5), heating body (7), connecting pipe (8), crucible (9), liquid level control rod (10), wherein the inner core (2) is placed in the outer shape (1), the inner core (2) and the outer shape (1) Between them is a mold cavity (1A), which is used to form the shape of a tube. The molten pool (1B) is set above the outer shape (1), and is connected to the crucible (9) through a connecting pipe (8), and the heating body (7) is placed Outside the shape (1), the liquid level control rod (10) is pressed into the crucible (9), one end of the dummy rod (5) is inserted into the cavity (1A), and the other end is exposed outside the cavity (1A). The cooler (3) and the drawing roll (4) are placed on the exposed end of the dummy bar (5). In this embodiment, the metal hydraulic pressure is above 0.045kg/cm ² . Dummy tube (5) is made with pure copper tube.

In order to increase the contact area between the inner core (2) and the molten metal. The heat of the molten metal is used to fully heat the inner core without additionally installing a heating body. The upper end of the inner core (2) is enlarged and provided with a channel (21).

In order to increase the pressure of the molten metal so that the molten metal can enter the narrow cavity, a molten pool (1B) is arranged above the above-mentioned shape (1).

The outer diameter of the tube formed by the above-mentioned outer shape (1) is 10 mm, and the inner diameter of the tube formed by the inner core (2) is 9 mm. The wall thickness of the tube is thus only 0.5 mm. In order to increase the surface area of the inner wall of the tube, several axially arranged grooves (2A) are evenly distributed on the outer circumference of the inner core (2). In this embodiment, 16 axially arranged grooves (2A) are evenly distributed on the outer circumference of the inner core (2). The width of the grooves (2A) is only 0.3 mm and the depth is 1 mm, corresponding to the formation of 16 ribs on the inner wall of the tube. . The cross-sectional shape of the mold is shown in Figure 2.

In Fig. 1, the thin-walled metal pipe is a cast pipe (6), and metallic copper is molten metal (11) after being melted in a crucible (9).

When producing thin-walled copper tubes with the technology of the present invention, the outer shape (1) is heated by the external heating body (7), and the inner core (2) increases the contact with the molten metal by the enlarged core head and the molten metal entering the channel. (11) The contact area is fully heated. Controlling the temperature of the molten metal can heat the inner core (2) to a required temperature, thereby heating and keeping the mold cavity above the melting temperature of copper. After the metal copper is melted in the crucible (9), the liquid level control rod (10) is pressed into the molten metal, so that the liquid level rises and enters the molten pool (1B) above the mold through the connecting pipe (8). Enter the cavity (1A) under pressure. Insert the dummy rod (5) into the cavity. After the upper end of the dummy rod (5) is fused with the molten metal in the cavity, the drawing roller (4) is started to pull the dummy tube (5) away from the mold, and the casting tube (6) is drawn out. Simultaneously, the dummy tube (5) is cooled by water spray from the cooler (3). Controlling the temperature of the mold, the temperature of the molten metal, the drawing speed and the distance from the cooler to the mold allows the metal to solidify just before leaving the mold. In this way, continuous casting of thin-walled tubes with complex cross-sectional shapes can be realized. The inner and outer surfaces of the cast pipe are extremely smooth, and the ribs are full and complete.

The present invention uses the heat of molten metal to heat the inner core of the casting mold, and uses the heating body to heat the outer shape, so that the temperature of the inner core and the outer shape are kept above the melting point of the casting metal; The combination of ingot rod and molten metal fusion makes the molten metal enter the narrow cavity. Therefore, the present invention does not need to install a heating body in the inner core of the mold, and can make the molten metal enter the narrow cavity smoothly and freely. Realize the production of thin-walled metal pipes with complex cross-sectional shapes and small sizes. In addition, the equipment used in the present invention has simple structure and high production efficiency. The invention is a convenient and practical process and equipment for producing thin-walled metal pipes by continuous casting.

Claims (9)

1. A process for producing thin-walled metal pipes by continuous casting, characterized in that it comprises the following steps: 1) Heat the outer shape of the mold with a heating body, and heat the inner core of the mold with the heat of molten metal, so that the temperature of the inner core and the outer shape are kept above the melting point of the cast metal; 2) Insert the dummy rod into the cavity so that its upper end is completely fused with the molten metal in the cavity. When the dummy rod is pulled down, the molten metal is brought into the narrow cavity, thereby casting a thin-walled tube with a complex cross-sectional shape; 3) Cool the dummy tube by spraying water from the cooler. 2. The process for producing thin-walled metal pipes by continuous casting according to claim 1, characterized in that the dummy rod is pulled out at a speed greater than 300mm/min in the above step 2). 3. The process for producing thin-walled metal pipes by continuous casting method according to claim 1, characterized in that the flow rate of water cooling in the above step 3) is 0.5-1.5 L/min. 4. An equipment for producing thin-walled metal pipes by continuous casting, characterized in that it includes a shape (1), an inner core (2), a cooler (3), a drawing roll (4), a dummy bar (5 ), heating body (7), connecting pipe (8), crucible (9), liquid level control rod (10), wherein the inner core (2) is placed in the outer shape (1), and the inner core (2) is connected with the outer shape Between (1) is a mold cavity (1A) to form the shape of a tube. The molten pool (1B) is located above the outer shape (1) and is connected to the crucible (9) through a connecting pipe (8). The heating body (7) Placed outside the shape (1), the liquid level control rod (10) is pressed into the crucible (9). Before continuous casting starts, one end of the dummy rod (5) is inserted into the cavity (1A), and the other end is exposed. Placed outside the cavity (1A), the cooler (3) and the drawing roller (4) are placed on the exposed end of the dummy bar (5). 5. The equipment for producing thin-walled metal pipes by continuous casting method according to claim 4, characterized in that the inner core (2) is enlarged at the upper end and has a channel (21). 6. The equipment for producing thin-walled metal pipes by continuous casting method according to claim 4, characterized in that a melting pool (1B) is set on the upper part of the above-mentioned shape (1). 7. The equipment for producing thin-walled metal pipes by continuous casting method according to claim 4, 5 or 6, characterized in that several axially arranged grooves (2A) are evenly distributed on the outer circumference of the inner core (2) . 8. The equipment for producing thin-walled metal pipes by continuous casting method according to claim 7, characterized in that 16 axially arranged grooves (2A) are evenly distributed on the outer circumference of the inner core (2). 9. The equipment for producing thin-walled metal pipes by continuous casting method according to claim 7, characterized in that the groove (2A) has a width of 0.3mm and a depth of 1mm.

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