淬火工艺对耐磨钢NM400组织性能的影响

采用微Nb、B,加少量Cr成分体系,研究不同离/在线淬火工艺对NM400钢显微组织和力学性能的影响,通过光学显微镜、SEM和TEM观察,分析离/在线淬火工艺对马氏体精细结构的演变规律。结果表明:在线淬火工艺马氏体块更细小,大角度晶界比例大,保留轧制奥氏体变形位错等缺陷,为碳化物在回火中析出提供位置,使析出物分布更弥散,同时拥有马氏体-下贝氏体复相组织,提高了钢的硬度、强度和韧性。

Effect of quenching on microstructure and properties of wear-resistant steel NM400

Effect of different off/on-line quenching processes on microstructure and mechanical properties of the NM400 steel microalloyed with Nb, B and a small amount of Cr was researched. Through optical microscope, SEM and TEM observation, the evolution of martensite sub-structure by off/on-line quenching process was analyzed. The results show that the size of martensite in on-line quenching process is smaller and the proportion of large angle grain boundaries is larger, the crystalline defects such as deformation dislocation of rolled austenite are retained, which provides the location for the precipitation of carbides during tempering, makes the distribution of precipitates more dispersed, and has martensite-lower bainite duplex structure improving the hardness, strength and toughness of steel.