Analysis of dimensional shrinkage issues of PH13-8Mo age-hardening stainless steel bushings after aging treatment
PH13-8Mo时效硬化不锈钢衬套时效处理尺寸收缩分析

摘要

PH13-8Mo时效硬化不锈钢衬套，在540℃时效处理后硬度约为HRC44.13，抗拉强度可达1483.0MPa，这是在时效处理过程中，Ni3Al、NiAl等第二相析出起到了强化作用。温度由540℃提升至620℃后，衬套的直径发生了明显收缩，内径收缩0.133mm，外径收缩0.115mm。除了应力导致表层材料发生微量的、不可逆的局部微观塑性流变之外，主要原因是在时效处理过程中，马氏体组织转变为逆转奥氏体，晶体结构发生了改变。同时，逆转奥氏体的存在使PH13-8Mo时效硬化不锈钢的强度、硬度大幅下降，而塑性明显提升，其伸长率可达19.88%。

Abstract

The hardness value of the PH13-8Mo age-hardening stainless steel bushing after aging treatment at 540℃ is approximately HRC 44.13, and the tensile strength can reach 1483.0 MPa. This is due to the precipitation of the second phase such as Ni3Al and NiAl during the aging treatment process, which plays a strengthening role. After the temperature was raised from 540℃ to 620℃, the diameter of the bushing shrank significantly, with the inner diameter shrinking by 0.133mm and the outer diameter shrinking by 0.115mm. Apart from the trace and irreversible local micro-plastic deformation of the surface material caused by stress, the main reason is that during the aging treatment process,the martensite structure transforms into reversed austenite, and the crystal structure changes. Meanwhile, reversing the presence of reversed austenite significantly reduces the strength and hardness of PH13-8Mo age-hardening stainless steel, while its plasticity is notably enhanced, with an elongation rate that can reach 19.88%.