热处理工艺对支撑辊用钢疲劳剥落形式的影响

Effects of Heat Treatment on the Fatigue Exfoliations of Back-up Roll Steels

采用JPM-1型接触疲劳磨损试验机，对450℃、530℃两个回火温度下支撑辊用Cr5钢的线接触滚动疲劳寿命进行了测定；通过扫描电子显微镜（SEM）、X射线（X—ray）和显微组织观察的方法研究了两种热处理工艺下试验用钢的疲劳剥落形式，并对剥落形式及剥落机理进行了初步探讨。结果表明：450℃回火得到硬度为HRC51的试样失效形式主要为棘齿裂纹和深层剥落，疲劳寿命为1．5～3×10^6；530℃回火得到硬度为HRC45的试样失效形式主要为浅层剥落，疲劳寿命为0．5～2×10^5。

The in-line contact rolling fatigue life of the Cr5-type steels was tested by using the JPM-1 type contact fatigue wear machine under the condition of two different tempering temperatures 450℃ and 530℃, respectively. The forms of the exfoliations were investigated by the means of SEM,XRD. Meanwhile, the forms and qualifications of the exfoliations were also preliminary discussed. The results show that the exfoliations for the sample with hardness HRC51 and HRCA5 are mainly in the forms of ratchet crack coexist with pockmark-type and pockmark-type at temperature of 450℃ and 530℃, corresponding to the fatigue life 15～3× 10^6 and 0. 5～2× 10^5 respectively.