CN205613850U - Plasticity equal channel angular extrusion device is sent to electricity - Google Patents

Abstract

The electroplastic equal-channel angular extrusion device disclosed by the utility model includes a mold with an extrusion channel, a metal workpiece is placed in the mold, an extrusion rod is arranged in the extrusion channel of the mold, and the extrusion rod is connected to the end of the metal workpiece. In contact, the metal workpiece is energized during extrusion using a conductive component connected to it in a closed loop. The electroplastic equal-channel angular extrusion device of the utility model is assisted by electric current during the equal-channel angular extrusion process, and the electric current will exert an electronic wind force on the dislocation, so that the movement ability of the dislocation is enhanced, the deformation resistance of the material is reduced, and the plasticity of the material is improved. Further strengthening can achieve grain refinement, improve the plasticity and strength of metal materials, reduce defects such as cracks in the deformation process of materials, and make the formability better; and in the extrusion process, the Joule heat generated by adjusting the current can be adjusted, Joule heat increases the heat of the metal during the deformation process, and combined with the heat of deformation, the plasticity of the metal becomes stronger.

Description

Electroplastic Equal Channel Angular Extrusion Device

technical field

The utility model belongs to the technical field of metal forming equipment, in particular to an electroplastic equal channel corner extrusion device.

Background technique

In the 1980s, Segal, an expert from the former Soviet Union, proposed a large plastic deformation processing method for preparing bulk fine-grained materials Equanl Channel Angular Processing (ECAP). After decades of development, this The technology has attracted great attention from the material circles at home and abroad. When preparing fine-grained materials, ECAP keeps the cross-sectional shape and size basically unchanged before and after deformation, so it can repeatedly make the material continuously produce large shear deformation, and the cumulative amount of each deformation is superimposed to obtain submicron grains or even nanometer Crystalline materials, so as to achieve the purpose of refining the grains, so as to improve the overall performance of the material. At present, ECAP has been successfully applied to the preparation of aluminum and aluminum alloys, copper and copper alloys, magnesium and magnesium alloys, etc., and has broad application prospects.

Research at home and abroad shows that during the ECAP process, process parameters such as the corner of the mold, extrusion path, extrusion speed, extrusion temperature, friction factors, and back pressure are the main factors affecting the ECAP processing performance of materials. When the traditional ECAP method is used to plastically deform the material, the extrusion speed has a great influence on the grain size of the material, but in order to ensure the extrusion efficiency, the extrusion speed must be increased. At a higher extrusion speed, it will cause The uniformity of the fine grain of the metal becomes worse, and at a higher extrusion speed, defects such as cracks are prone to appear for materials with poor plasticity, and even fracture will lead to a decrease in the formability and forming rate of the material.

Utility model content

The purpose of the utility model is to provide an electroplastic equal-channel angular extrusion device, which solves the problem of poor metal fine-grain uniformity, formability, and forming problems caused by the rapid extrusion speed of the existing equal-channel angular extrusion method. rate of decline.

The technical solution adopted by the utility model is: an electroplasticity etc. channel corner extrusion device, including a mold with an extrusion channel, a metal workpiece is placed in the mold, an extrusion rod is arranged in the extrusion channel of the mold, and the extrusion rod In contact with the end of the metal workpiece, the metal workpiece is energized during the extrusion process with a conductive component connected to it in a closed loop.

The utility model is also characterized in that,

The conductive assembly includes a conductive extruding rod, a pressure device, a power supply and a conductive block connected in sequence through wires, the conductive extruding rod passes through the side wall of the mold and is connected to the back of the metal workpiece, and the conductive block is connected to the outlet end of the metal workpiece.

The conductive assembly also includes a transformer in series with the power supply.

The working surface where the conductive block is in contact with the extruded workpiece is a metal sheet, and the rest is made of hard plastic, and the wire passes through the hard plastic to connect with the metal sheet.

The top of the extruded rod is provided with an insulating coating.

The location of the conductive extruded rods is where the metal workpiece is subjected to shear stress.

The position of the conductive extrusion rod is in the deformation dead zone of the metal workpiece.

The beneficial effects of the utility model are: the electroplastic equal-channel angular extrusion device of the utility model solves the problem of poor metal fine-grain uniformity and formability when the extrusion speed of the existing equal-channel angular extrusion method is fast. , The problem of lower molding rate. The electroplastic equal-channel angular extrusion device of the utility model is assisted by electric current in the process of equal-channel angular extrusion, and the electric current will exert an electronic wind force on the dislocation, so that the movement ability of the dislocation is enhanced, the deformation resistance of the material is reduced, and the deformation resistance of the material is improved. The plasticity is further strengthened. This phenomenon is called electroplasticity. Electroplasticity can achieve the effect of refining grains, improving the plasticity and strength of metal materials, reducing defects such as cracks in the deformation process of materials, and making the formability better; and in In the process of electroplastic equal channel angular extrusion, low voltage and high current are used. By adjusting the current, the generated Joule heat can be adjusted. Joule heat increases the heat of the metal during deformation, and combined with the heat of deformation, it makes the metal plastic Become stronger.

Description of drawings

Fig. 1 is a schematic structural view of the electroplastic equal channel corner extrusion device of the present invention;

Fig. 2 is a partially enlarged schematic view of the electroplastic equal channel angular extrusion device of the present invention.

In the figure, 1. extrusion rod, 2. mold, 3. conductive extrusion rod, 4. presser, 5. power supply, 6. transformer, 7. conductive block, 8. metal workpiece.

detailed description

The structure of the electroplastic equal-channel angular extrusion device provided by the utility model is shown in Figure 1 and Figure 2, including a mold 2 with an extrusion channel, a metal workpiece 8 is placed in the mold 2, and a metal workpiece 8 is placed in the extrusion channel of the mold 2. An extruding rod 1 is provided, and the extruding rod 1 is in contact with the end of the metal workpiece 8, and the metal workpiece 8 is energized during the extrusion process by means of a conductive component connected to it in a closed loop.

Exemplarily, the conductive assembly includes a conductive extruding rod 3, a pressure device 4, a power supply 5 and a conductive block 7 connected in sequence by wires. The conductive extruding rod 3 passes through the side wall of the mold 2 and is connected to the back of the metal workpiece 8. Conductive Insulation is maintained between the extrusion rod 3 and the side wall of the mold 2 , and the conductive block 7 is connected with the outlet end of the metal workpiece 8 .

The pressure device 4 is used to make the metal workpiece 8 receive back pressure during the extrusion process, so that the dead zone during the deformation process of the metal workpiece 8 is reduced, so that the plastic fluidity can be improved.

Preferably, the conductive component further includes a transformer 6 connected in series with the power supply 5, and the transformer 6 is used to change the size of the conductive current.

The outlet end and the end of the metal workpiece 8 are distinguished relative to the direction in which the workpiece is placed during extrusion, and the end that is put into the mold earlier is the outlet end.

The conductive block 7 is used to facilitate the connection of the outlet end of the extruded metal workpiece 8 with the power supply 5. The conductive block 7 has only the front part and the contact surface of the metal workpiece 8 to conduct electricity, and for reducing the friction between the conductive block 7 and the mold 2, the conductive block 7 and the metal The working surface that the workpiece 8 is in contact with is a metal sheet, and the rest is made of hard plastic, and the wire passes through the hard plastic to connect with the metal sheet.

The top of the extruding rod 1 is provided with an insulating coating to prevent the current from entering the extruder and causing damage to the extruder.

When processing a metal workpiece 8 of a corresponding size, apply lubricating oil, the concentration should not be too high, put the metal workpiece 8 into the mold 2, put it into the extruding rod 1, and connect it to electricity, and place the conductive block 7 at the outlet end of the metal workpiece. Cooperate, and place the entire mold 2 on an insulated workbench, then turn on the power supply 5, adjust the current and voltage through the transformer 6, and extrude with an extruder. After the deformation and extrusion are completed, take out the sample and record the extrusion deformation direction, record current and back pressure.

Preferably, the length of the extrusion rod 1 that can penetrate into the mold 2 is 1mm-2mm longer than the depth of the mold 2, which is beneficial to control the amount of extrusion deformation. The matching gap between the extrusion rod 1 and the mold 2 is 0.5mm-1mm, ensuring that the metal workpiece 8 It is not easy to flow to the gap.

Preferably, the front end of the conductive extruded rod 3 is 1mm-2mm wider than the extruded rod itself, so as to ensure the strength of the front end and ensure that the heat generated by the contact resistance is not easy to damage the front end.

The current, voltage and back pressure are adjusted according to the extrusion situation, and the A path (the workpiece does not rotate every pass), the Ba path (the workpiece rotates 90° each pass), and the Bc path (the workpiece rotates every pass) of the traditional ECAP can be used. Passes rotate 90° in the same direction), C path (the workpiece rotates 180° in each pass) for extrusion, but the direction and angle change when the material enters the mold. This is a conventional technical means in the art, here No longer.

Preferably, the position where the conductive extrusion rod 3 is placed is the part where the metal workpiece 8 is subject to shear stress during the ECP process. Since the metal workpiece 8 undergoes shear deformation here, the application of current makes the shear stress The effect of shear deformation is strengthened, which makes it easier to increase the fluidity of the metal.

Preferably, the position of the conductive extruding rod 3 is in the deformation dead zone of the metal workpiece 8, so that the pressure given by the pressure device 4 is applied on its back and the current is applied at the same time, the purpose is to increase the metal fluidity in the dead zone, and at the same time make The degree of refinement of the grains of the metal workpiece 8 increases.

The utility model will be described in detail below in conjunction with the accompanying drawings and two comparative examples.

Example 1

The AZ31 magnesium alloy is extruded using the traditional ECAP process die and method. The intersection angle of the two channels of the die is 90°, the outer arc is 20°, the extrusion path is Bc, the heating temperature is 300°C, and the extrusion speed is 15mm. /min, 300KN extruder, the metal material broke during the second pass of extrusion. When using the electroplastic equal-channel corner extrusion device of the utility model for extrusion, 8000Hz pulse voltage is used, the extrusion path is Ba, and the heating temperature is 300°C. Microcracks appear in the material after the seventh pass of extrusion , to observe the metal grains, the size of the metal grains is small.

Example 2

When using the same ECAP die to extrude 2A11 aluminum alloy, the lubricant used is a mixture of graphite powder and engine oil, and the extrusion path is Bc. The sample cracks after repeated 8-pass cold deformation in a 300KN extrusion machine. The extrusion speed is 18mm/min, the grain size of the obtained metal is about 210nm, and the hardness value is 108Hv. When using the electroplastic equal-channel corner extrusion device of the utility model for extrusion, a 6000Hz pulse current is used, and no cracks appear in the workpiece after extrusion for 10 passes, and the metal grains are observed, and the metal grains The size is about 180nm, and the metal grains obtained after the above-mentioned ECAP process are refined, and the hardness value is also improved.

Compared with the existing ECAP technology, the electroplastic equal channel angular extrusion device of the utility model has the following advantages:

1. On the basis of ensuring the extrusion rate, it can also achieve the purpose of refining metal grains;

2. Electroplastic equal-channel angular extrusion will generate Joule heat during the extrusion process, which reduces the heat required for the hot-extruded metal, reduces the heat dissipation rate, reduces energy consumption, and reduces the heating time of the workpiece , which improves the extrusion efficiency;

3. On the basis of ensuring the formability and refinement effect, the electronic wind force can increase the extrusion rate during the extrusion process, saving time and economic costs;

4. The electronic wind effect strengthens the dislocation movement of the material, which makes the plastic fluidity of the metal better and the grains of the metal are refined. At the same time, research shows that the residual stress on the surface of the workpiece can be reduced, and the comprehensive performance of the processed material can be improved.

Claims (7)

1. Electroplastic equal channel angular extrusion device is characterized in that, comprises the mold (2) that has extruding passage, is placed with metal workpiece (8) in described mold (2), and the extrusion of described mold (2) An extruding rod (1) is arranged in the pressing channel, and the extruding rod (1) is in contact with the end of the metal workpiece (8). power on during the process. 2. The electroplastic equal channel angular extrusion device according to claim 1, characterized in that, the conductive assembly comprises a conductive extrusion rod (3), a presser (4), a power supply (5) connected in sequence by wires ) and a conductive block (7), the conductive extrusion rod (3) passes through the side wall of the mold (2) and is connected to the back of the metal workpiece (8), and the conductive block (7) is connected to the The outlet ends of the metal workpiece (8) are connected. 3. The electroplastic equal channel angular extrusion device according to claim 2, characterized in that, the conductive component further comprises a transformer (6) connected in series with the power supply (5). 4. The electroplastic equal channel corner extrusion device according to claim 2, characterized in that, the working surface of the conductive block (7) in contact with the extruded workpiece (8) is a metal sheet, and the remaining parts are hard hard plastic, and the wire passes through the hard plastic and is connected to the metal sheet. 5. The electroplastic equal channel angular extrusion device according to claim 1, characterized in that an insulating coating is provided on the top of the extrusion rod (1). 6. The electroplastic equal channel angular extrusion device according to claim 1, characterized in that, the position of the conductive extrusion rod (3) is at the position where the metal workpiece (8) is subjected to shear stress. 7. The electroplastic equal channel angular extrusion device according to claim 1, characterized in that, the position of the conductive extrusion rod (3) is in the deformation dead zone of the metal workpiece (8).