热处理工艺对疏浚工程用船体钢组织及磨粒磨损性能的影响

为了提高疏浚工程船用低碳低合金耐磨钢的耐磨性能,分别采用淬火+200 ℃低温回火、淬火+250 ℃配分、循环热处理3种热处理工艺对试验钢进行热处理,并借助扫描电镜与透射电镜分析组织与析出相,磨粒磨损试验机测试磨损质量损失,硬度计测试热处理钢的硬度。结果表明,试验钢淬火+200 ℃回火后得到回火马氏体,基体中有少量碳化物,回火马氏体仍呈板条状;淬火-配分试验钢得到马氏体加较多残留奥氏体;经循环热处理后,试验钢中马氏体板条消失,基体中有颗粒状(Nb,Ti)C析出相。试验钢淬火-回火后硬度为39.5 HRC,淬火-配分试验钢硬度为40.5 HRC,循环热处理试验钢硬度30.8 HRC。试验钢耐磨性与硬度成正比,试验钢经循环热处理后,磨损量最大,耐磨性能最差,淬火-回火试验钢次之,淬火-配分钢耐磨性能最好。3组试验钢磨粒磨损后试样表面均出现大量犁沟,磨损机制主要是塑性变形。

Effect of heat treatment process on microstructure and abrasive wear properties of dredging engineering ship steel

In order to improve the wear resistance of low-carbon low-alloy wear-resistant steel for dredging engineering ships, three kinds of heat treatment processes of quenching-tempering at 200 ℃ (Q-T), quenching-partitioning at 250 ℃ (Q-P), and cyclic heat treatment (CR) were carried out respectively on the tested steel. The microstructure and precipitated phase were analyzed by scanning electron microscope (SEM) and transmission electron microscopy (TEM), the wear mass loss and the hardness were tested respectively by abrasive wear tester and hardness tester. The results show that after the quenching-tempering treatment, tempered martensite still with lath substructure and a small amount of carbides are obtained. Martensite and more retained austenite are obtained in the tested steel after quenching-partitioning. After cyclic heat treatment, the martensite laths in the tested steel disappear, and there are granular (Nb,Ti)C precipitates in the matrix. The hardness of the tested steel after quenching-tempering, quenching-partitioning and cyclic heat treatment is 39.5, 40.5, and 30.8 HRC, respectively, and the wear resistance of the tested steel is proportional to the hardness. The tested steel has the largest amount of wear mass loss and the worst wear resistance after cyclic heat treatment, while the tested steel has the second best wear resistance after quenched-tempering, and the tested steel has the best wear resistance after quenching-partitioning. For all the 3 groups of tested steel specimens, a large number of furrows appear on the surface of the specimens after abrasive wear, and the wear mechanism is mainly plastic deformation.