Continuous extrusion deformation method of magnesium alloy

Abstract

The invention discloses a continuous extrusion deformation method of magnesium alloy, which comprises the steps that: the temperature of a homogenized magnesium alloy blank is heated to 350 to 450 DEG C, an extrusion die, with the temperature lower than that of the magnesium alloy blank by 10 to 30 DEG C, is used for performing first-pass one-way continuous extrusion at the constant-speed extrusion rate of 1m / min to 3m / min in an order of forward extrusion, change channel angular extrusion at 90-degree corner and equal channel angular extrusion at 90-degree corner, so that the magnesium alloy blank, after the forward extrusion at one end of the die, is equivalently divided into a plurality of streams, which are subject to the change channel angular extrusion and the equal channel angular extrusion to form the magnesium alloy at the other end of the die, followed by mold stripping, thus continuous flowing extrusion deformation is formed, the extrusion ratio of the forward extrusion to the change channel angular extrusion at 90-degree corner is 16:1, and the extrusion ratio of the change channel angular extrusion to the equal channel angular extrusion at 90-degree corner is 1:1. The method can not only obtain extremely prominent grain refining effect and more homogenous structure of the magnesium alloy, but can also enhance industrial production efficiency, lower production cost and ensure production quality by increasing the extrusion ratio and the extrusion speed.

Description

technical field [0001] The invention relates to the field of extrusion deformation of magnesium alloys, in particular to a continuous extrusion deformation method of magnesium alloys. Background technique [0002] Magnesium alloy is currently the lightest metal structure material. It has electrical conductivity, thermal conductivity, and electromagnetic shielding properties. At the same time, it has good performance, high specific strength and specific stiffness, good shock absorption, good cutting processing and dimensional stability, and is easy to recycle. It is beneficial to environmental protection and other advantages, and is known as "the green engineering material of the 21st century". With the development of light weight in industries such as automobiles, aviation, electronics and transportation, the application range of magnesium alloys is becoming wider and wider. Magnesium alloys are divided into cast magnesium alloys and wrought magnesium alloys. At present, cas...

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Problems solved by technology

Although this method can realize the refinement of magnesium alloy grains to a very small degree, it has several shortcomings: first, the billet needs to be preliminarily refined by pre-extrusion deformation, so there are many processes, equipment and energy consumption Large, high cost: Second, multi-pass extrusion processing is used, the same process is many, the production efficiency is low, and the production cost is high; and because the extrusion speed of the equal channel angular extrusion (ECAE) technology is 0.1 ~ 0.8m / min, the extrusion time of each pass is relatively long, and the production efficiency is low. If the one-way extrusion speed is increased, the product quality will decrease

Therefore, in the case that industrial production needs to improve production efficiency, the equal channel angular extrusion (ECAE) technology obviously has deficiencies, and it is quite difficult to popularize and apply it in industrial production.

[0006] Because the variable channel angular extrusion (CCAE) is characterized by adding a certain extrusion ratio on the basis of equal channel angular extrusion, the magnesium alloy billet with a grain size of 500 μm can be passed through one pass with an extrusion ratio of The 4:1 extrusion makes the grain size reach 25 μm, and the grain refinement ratio is 20:1, which improves the grain refinement effect of the magnesium alloy; shape structure, the uniformity of the grain becomes worse, and the mechanical properties of the magnesium alloy are reduced, and the extrusion ratio of the existing variable channel angular extrusion (CCAE) is usually controlled within 10:1, such as once the extrusion ratio reaches or More than 10:1, the magnesium alloy is prone to cracks, and when the extrusion speed is greater than 2m / min, the mold is also prone to cracking and damage

If it is necessary to extrude and deform a magnesium alloy billet with a thicker diameter into a profile with a thinner diameter, the current equal-channel angular extrusion and variable-channel angular extrusion must go through multi-pass extrusion. The diameter is gradually extruded to a small diameter in passes, and the mold must be removed and replaced every time the diameter is changed. The procedures are many and complicated, which wastes time and resources in actual production; Cracks occur at the usual extrusion temperature of 350-450°C. If variable channel angle extrusion is used, after the extrusion ratio of each pass reaches 10:1, the extruded material is prone to cracks, which will affect the product. quality

[0007] It can be seen that if a higher extrusion ratio and faster extrusion speed are required to improve the industrial production efficiency of magnesium alloy extrusion deformation, and at the same time improve the effect of magnesium alloy grain refinement and ensure product quality, the above extrusion methods are difficult. Reach, therefore need a kind of magnesium alloy extrusion deformation method that can improve production efficiency, guarantee product quality in the industrialized production of magnesium alloy extrusion deformation, make deformed magnesium alloy products can be widely used in industrialized production

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