热轧中锰马氏体耐磨钢的冲击磨损行为

 利用MLD-10型动载磨料磨损试验机,系统研究了热轧中锰马氏体耐磨钢在1、2.5和5 J冲击能量作用下的冲击磨料磨损行为,并与Hardox450钢进行了比较。借助光学显微镜(OM)、扫描电子显微镜(SEM)和布氏硬度计等设备分析了试验钢的组织、力学性能及磨损表层、亚表层,并探讨了其磨损机制。研究结果表明,试验钢的显微组织为板条马氏体,与Hardox450钢相比,其布氏硬度更高,-40 ℃下的冲击吸收能量更低,分别为503HB和15.3 J。相同工况条件下,试验钢的磨损失重明显小于Hardox450钢,且基于有效磨损时间修正后的磨损率均随着冲击能量的升高,呈现出先增大后减小的趋势。当冲击能量为2.5 J时,磨损率最大,磨损失重量最多。原因在于,冲击能量较低时,试验钢的磨损主要以犁沟为主,并伴随着少量的磨粒嵌入,磨损失重较少;当冲击能量为2.5 J时,磨损表面的切削加剧,且塑性变形造成大量磨粒嵌入基体,导致应力集中,并在反复冲击过程中产生疲劳裂纹,随后扩展至试验钢表面,形成疲劳剥落,磨损亚表层出现明显剥落坑,失重显著增加;当冲击能量为5 J时,磨损表面塑性变形增加,加工硬化显著,疲劳磨损占据主导,磨损表面硬度较高,犁沟和磨粒嵌入较少,磨损亚表层更为平整均匀,失重反而减少,磨损率下降。

Impact abrasive wear behavior of hot-rolled medium manganese martensitic wear-resistant steel

The impact abrasive wear behavior of hot-rolled medium manganese martensite wear-resistant steel under the impact energy of 1 J, 2.5 J and 5 J was systematically studied by MLD-10 dynamic load abrasive wear tester, and compared with that of Hardox450 steel. With the help of optical microscope (OM), scanning electron microscope (SEM) and Brinell hardness tester, the microstructure, mechanical properties, wear surface layer and sub-surface layer of the test steel were analyzed, and the wear mechanism was discussed. The results show that the microstructure of the experimental steel is lath martensite. Compared with Hardox450 steel, the Brinell hardness of the experimental steel is higher, and the impact absorption energy at -40 ℃ is lower, which is 503 HB and 15.3 J respectively. Under the same working conditions, the wear weight loss of the test steel is obviously smaller than that of Hardox450 steel, and the wear rate corrected based on the effective wear time increases first and then decreases with the increase of impact energy. When the impact energy is 2.5 J, the wear rate is the highest and the grinding loss is the largest. The reason are as follows. When the impact energy is low, the wear of the test steel is mainly furrow, accompanied by a small amount of embedded abrasive particles, resulting in less wear loss; When the impact energy is 2.5 J, the cutting of the worn surface is intensified, and the plastic deformation makes a large number of abrasive grains to embedded in the matrix, resulting in stress concentration, which leads to fatigue cracks in the repeated impact process, and then extends to the surface of the experimental steel, resulting in increased fatigue wear and spalling of the matrix, obvious spalling pits in the worn sub-surface, and significantly increase in weight loss. When the impact energy is 5 J, the plastic deformation of the worn surface increases, the work hardening is obvious, fatigue wear dominates, the hardness of the worn surface is higher, the furrows and abrasive grains are less embedded, the worn sub-surface layer is more even, the weight loss decreases, and the wear rate decreases.