A Method for Eliminating Residual Stress of High Strength Rare Earth Magnesium Alloy Thin-Wall Castings

Abstract

The method relates to a method for relieving residual stress of a high-strength rare earth magnesium alloy thin-walled casting, and belongs to the technical field of nonferrous metal processing technologies. By the adoption of the method, the residual stress in the high-strength magnesium alloy WNG421 casting can be effectively relieved, and meanwhile the residual stress can be homogenized. Moreover, the hot isostatic pressure technology can improve the mechanical properties of magnesium alloy casting materials. As for WNG421 magnesium alloy, the strength value and ductility are both improved.

Description

technical field [0001] The invention relates to a method for eliminating residual stress of high-strength rare-earth magnesium alloy thin-walled castings, which belongs to the technical field of nonferrous metal processing, and in particular to a process that integrates elimination of residual stress of high-strength rare-earth magnesium alloy thin-walled castings and improvement of mechanical properties , said high-strength rare earth magnesium alloy refers to Mg-Y-Nd series high-strength magnesium alloy. High strength refers to the mechanical properties of the magnesium alloy, and the tensile strength is not less than 300MPa. Thin-walled castings refer to the wall thickness of the castings not greater than 3.5mm. Background technique [0002] High-strength rare earth magnesium alloy WNG421 (Mg-4Y-2Nd-1Gd) blank castings, heat treatment deformation and mechanical processing all produce residual stress. Long-term storage stress release makes it difficult to ensure high-preci...

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Problems solved by technology

The main reason for the reduction of stress by the cold and hot cycle treatment method is that the original residual stress of the material and the stress generated by the cold treatment cancel each other out. This method is only suitable for parts with simple shapes and good symmetry, otherwise it will easily cause deformation of the workpiece and is not suitable for thin-walled parts. The stress relief treatment, in addition to the higher cost

Vibration aging is to apply a periodic excitation force to the workpiece. The frequency of the excitation force is the same as the natural frequency of the part, so that the part undergoes resonant motion, and the alternating external load is transmitted to each part of the part through resonance. When the additional external load and the residual The stress is superimposed, and the material parts are slightly distorted, so as to achieve the purpose of reducing and homogenizing the residual stress. This method is repeatedly tested and the cost is high.

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