A heat treatment process for large-scale high-strength deformed magnesium alloy forgings

Abstract

The invention relates to a thermal treatment technology of a large-size high-strength wrought magnesium alloy forging, and particularly relates to a thermal treatment technology of a wrought magnesium alloy forging of an Mg-Al-Zn system. The implementation scheme of the invention is as follows: preserving heat of the large-size wrought magnesium alloy forging with the wall thickness of 30-100mm, the diameter (phi) of greater than or equal to 680mm and the maximum horizontal projection area of greater than or equal to 0.4m<2> at 80-100 DEG C for 36-48 hours; heating to 160-180 DEG C at a rate of 15-30 DEG C per hour, and preserving heat for 15-20 hours; and cooling to room temperature to obtain the large-size high-strength wrought magnesium alloy forging, wherein the magnesium alloy forging comprises the following elements in percentage by mass: 8.2-8.5% of Al, 0.4-0.5% of Zn, 0.2-0.25% of Mn, less than or equal to 0.05% of Cu, less than or equal to 0.005% of Ni, less than or equal to 0.15% of Si, less than or equal to 0.02% of Be, less than or equal to 0.05% of Fe, less than or equal to 0.3% of other impurities and the balance of Mg. By adopting the technology provided by the invention, the prepared large-size high-strength wrought magnesium alloy forging can meet the using requirements for the parts of the fields of transportation, aerospace and the like; and the preparation technology is simple and easy to implement, and industrial production is facilitated.

Description

technical field [0001] The invention relates to a heat treatment process for a large-size high-strength deformed magnesium alloy forging, in particular to a heat treatment process for a large-size deformed magnesium alloy forging of the Mg-Al-Zn system. Background technique [0002] Mg-Al-Zn series alloys are relatively commonly used deformed magnesium alloys. They are low in price and are suitable for wide application. This series of alloys can not only carry out plastic deformation, but also have aging strengthening effects. Aging strengthening treatment can greatly improve its mechanical properties. Die forging has the advantages of high production efficiency, the ability to form forgings with complex shapes, accurate forging dimensions, full use of materials, reduction of processing residues, and improvement of material strength and plasticity. Magnesium alloy heat treatment usually adopts T5 and T6 heat treatment, T5 is artificial aging directly after casting or proces...

AI Technical Summary

Problems solved by technology

It should be noted that for large-sized parts with complex shapes and uneven wall thicknesses, when T5 is processed, due to the phenomenon of different deformations in various places during die forging, the stress storage energy in various places inside the parts is different.

Aging at a single temperature will lead to different order and size of strengthening phase precipitation at different positions, that is, the position with large deformation energy storage is preferentially precipitated, and when the position with small deformation storage energy reaches the aging peak, the position with large deformation energy storage has already occurred Aging, resulting in uneven performance everywhere

[0004] At present, there is no report in the relevant literature on the process of using a multi-stage aging system to treat die forgings with complex shapes and differences in wall thickness.

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