Backpressure equal-channel angular extruding mould

A mold and back pressure technology, applied in the field of material processing and extrusion, can solve the problems of complicated operation, low extrusion efficiency, no back pressure device, etc., and achieve good tissue uniformity, increase cross-sectional area, and improve extrusion efficiency. Effect

Active Publication Date: 2012-08-01
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although many ECAP extrusion dies have been researched and developed at home and abroad, the existing dies still have the following disadvantages: (1) adopt a simple single punch type punch, such as patents CN2584308, CN1712155, CN1357240, etc.
The biggest disadvantage of the punch-type punch is its low rigidity. When extruding difficult-to-deform magnesium alloys, a large pressure is required, which is prone to bending and instability.
(2) The working efficiency of the mold is low. Every time a sample is extruded, the mold needs to be disassembled to take out the sample or knocked out from the horizontal channel, which is cumbersome to operate
(3) Most of the existing molds do not have back pressure devices, and can only be extruded by traditional extrusion processes, such as CN101797596, CN1792487, etc.
But there are the following defects: (1) the simple punch type punch is adopted, the punch rigidity is not high, and it is prone to bending and instability; (2) the requirements for the hydraulic press are relatively high, and only the three-way hydraulic press can be extruded with this die Magnesium alloy, two-way hydraulic press cannot be used
(3) After one sample is extruded, the mold needs to be disassembled to take out the sample. The operation is cumbersome and the efficiency is low. Multiple samples cannot be continuously extruded.
[0007] To sum up, it can be seen that most of the existing dies can only be extruded under the traditional process, and cannot be extruded at a lower temperature for difficult-to-deform magnesium alloys, and the extrusion efficiency is low

Method used

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  • Backpressure equal-channel angular extruding mould

Examples

Experimental program
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Effect test

Embodiment 1

[0037] 7. After the mold and the sample reach the predetermined temperature, set the pressure of the back pressure, put the sample into the extrusion groove between the two guide rods, and squeeze the sample for the first pass, and the same pass can be carried out Multiple samples are continuously extruded, and the next sample is extruded from the previous sample from the horizontal channel, which is easy to operate and does not need to dismantle the mold. After 1-4 passes of extrusion, 4 samples are extruded in each pass. After 1-4 passes, the plasticity of the sample has been improved, so the 5-8 passes of the sample can be extruded at a lower temperature without cracks. Reduce the temperature of the mold and the sample, and extrude at a lower temperature for 5-8 passes. When the difficult-to-deform magnesium alloy is extruded under the traditional ECAP die and process, it can only be extruded at a relatively high temperature, and the sample will break when the temperature ...

Embodiment 2

[0041] Experimental results: According to Jin Li's doctoral thesis, through two-step ECAP deformation, 1-4 passes at 225°C, and 5th pass at 180°C, the grains are refined to about 1um. When extruding with the present invention, a back pressure of 50Mpa is applied during extrusion, and the 1-4 passes are extruded at 225°C, the extrusion temperature of the 5th pass can be reduced to 150°C, and the grains are refined to about 0.7μm , Yield strength increased from 230Mpa to 290Mpa. , Example 2: Equal channel angle extrusion rare earth magnesium alloy GW103

[0042] GW103 is a rare earth magnesium alloy with relatively high hardness and poor plasticity. It needs to be extruded at a higher temperature when extruded with a traditional mold. The mold is easily damaged due to excessive pressure, and the strength and structure of the mold are also high. .

[0043] Cut the sample into a square sample of 12 × 12 × 12mm as in Example 1, install the mold according to the steps in Example 1...

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Abstract

The invention discloses a backpressure equal-channel angular extruding mould which comprises a pressing plate, a guide pillar, a knocking bar, a convex mould, a guide sleeve, a spring, a concave mould, a mould base, a double-fork type punching head, a heating ring, a positioning slide block, a backpressure ejecting rod and an ejecting rod bracket, wherein the rigidity and strength of punching head are increased by the double-fork type punching head; the positioning slide block capable of sliding back and forth is arranged in a horizontal channel, so that the last sample can be conveniently taken out from the horizontal channel; and backpressure is applied to the sample by a backpressure device in an ejecting rod pressurizing form during an extruding process, so that the extruding temperature is efficiently reduced, the grain is refined and the comprehensive mechanical property of magnesium alloy is improved.

Description

technical field [0001] The invention relates to the technical field of material processing and extrusion, and relates to a high-efficiency back pressure equal channel angle extrusion die. Background technique: [0002] With the development of manufacturing industries such as modern automobiles and aerospace, magnesium alloys are widely recognized for their excellent performance. [0003] growing attention. Magnesium alloys have the lowest density (about 1.74g / cm2) among practical materials. 3 ), high specific strength and specific stiffness, and good damping, good machinability, good electrical and thermal conductivity, the application in automobiles and spacecraft can effectively reduce the overall quality of the product, and has great development potential. [0004] Since the magnesium alloy has a hexagonal close-packed structure, there are only 3 movable slip systems and 2 independent slip systems, and the ductility at room temperature is poor, which limits the wide app...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21C25/02
Inventor 李德江周银鹏曾小勤汤晓明丁文江
Owner SHANGHAI JIAO TONG UNIV
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