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金属工件在焊接、铸锻和机械加工的过程中,由于冷热的急剧变化或外力作用,容易造成大量的应力残留,且应力处于亚稳定状态。在金属工件服役的过程中,残留应力会缓慢释放,从而造成工件变形,降低尺寸精度。通常在工件服役之前进行时效处理释放应力,常用方法有自然时效、热时效及振动时效。自然时效即把金属工件放置在自然环境中使应力松弛,其周期长、占地面积广,效率低。热时效利用热源把工件加热到一定温度,使工件处于高温的塑
Metal parts in welding, casting and machining process, due to rapid changes in hot or cold or external forces, likely to cause a large number of residual stress, and stress in a metastable state. In the process of serving metal parts, the residual stress will be slowly released, resulting in deformation of the workpiece, reducing dimensional accuracy. Aging is usually performed before the workpiece is released to relieve stress. Common methods include natural aging, thermal aging and vibration aging. Natural aging that is placed in the metal parts of the natural environment so that stress relaxation, its long cycle, covering a wide area, low efficiency. Thermal aging using the heat source to the workpiece heated to a certain temperature, the workpiece in high temperature plastic