Magnesium alloy extrusion deforming processing method

Abstract

The magnesium alloy extruding deformation process includes the following steps: heating the extruding die for bidirectional extrusion and flowing diameter change and painting lubricant to the extrusion passage, heating magnesium alloy blank through homogenizing treatment and setting into the extrusion passage, and bidirectional extrusion on the magnesium alloy blank from its two ends with two male dies moving in opposite direction in the speed of 1.5-2.5 m / min and force of 2.5-5 MPa to realize flowing extrusion deformation. The magnesium alloy extruding deformation process can fine the crystal grain of magnesium alloy greatly, raise its comprehensive mechanical performance, low extrusion temperature and high production efficiency.

Description

technical field [0001] The invention belongs to the field of extrusion deformation of magnesium alloys, in particular to a processing method for extrusion deformation of magnesium alloys. Background technique [0002] Magnesium alloy has a close-packed hexagonal crystal structure with low symmetry. Its axial ratio (c / a) value is 1.623, which is close to the ideal close-packed value of 1.633. There are few slip systems at room temperature and poor plastic deformation ability. Among all the deformation methods of magnesium alloys, extrusion deformation is relatively easy, and it is easy to form a large productivity, and the performance of the material obtained after deformation is also greatly improved. Plasticity is one of the important mechanical properties of wrought magnesium alloys, which determines the plastic forming performance and serviceability of materials, parts and components. The research and development of wrought magnesium alloy materials in my country is stil...

AI Technical Summary

Problems solved by technology

[0003] At present, the extrusion deformation of magnesium alloys in industrial production adopts unidirectional extrusion, and the extrusion temperature of the magnesium alloy billet is usually 350-450°C, and the extrusion speed is usually 1m / min-2.5m / min. min, the extrusion temperature of this unidirectional extrusion method is proportional to the extrusion speed, the lower the extrusion temperature, the slower the extrusion speed, if the extrusion temperature decreases without the extrusion speed slowing down, the magnesium alloy The molding effect will be affected, resulting in cracks in the extruded material and affecting product quality

Referring to Figure 9, the state-of-the-art unidirectional extrusion deformation method of magnesium alloys is ECAE (Equal channel angular extrusion), which is a large-scale method that uses pure shear deformation to refine grains. In the plastic deformation processing method, the magnesium alloy billet 13 to be extruded is extruded through a one-way equal-diameter extrusion channel 14 bent at an angle of 90 degrees on the extrusion die 12, so that the magnesium alloy billet is squeezed on the side of an extrusion rod 11 Under pressure, the one-way equal-diameter extrusion channel moves from one end to the other end, so that the magnesium alloy billet is sheared and deformed when passing through the 90-degree corner of the one-way equal-diameter extrusion channel, the magnesium alloy grains are refined, and the The mechanical properties of the extruded magnesium alloy material, but because this extrusion method is only a one-way equal-diameter channel extrusion method, the extrusion ratio is 1, the extrusion temperature is 300-350 ° C, and the extrusion speed is 0.6~1.2m / min, after each extrusion pass, the degree of refinement of the magnesium alloy grain size cannot reach 1 / 2, and it takes multiple passes of extrusion to refine the magnesium alloy grain size to a smaller size

For example, if a magnesium alloy billet with a grain size of 210 μm is extruded by ECAE technology, eight times of extrusion are required before the grain size of the magnesium alloy can reach below 10 μm. To a small extent, but because of the multi-pass extrusion process, its production efficiency is reduced; and because the extrusion speed of ECAE technology is 0.6-1.2m / min, the extrusion time of each pass is relatively long, and the same As a result, its production efficiency is reduced. If the extrusion speed of unidirectional extrusion is to be increased, the product quality will be reduced.

Therefore, in the case that industrial production needs to improve production efficiency, ECAE technology obviously has deficiencies.

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