S30432钢出现马氏体组织时的力学性能试验研究

摘要

In order to evaluate the long-term service security of S30432 steel containing martensitic structure,the mechanical properties and fracture mechanism of S30432 steel are studied by using XRD,SEM,TEM,tensile testing machine,impact testing machine and Vickers hardness testing machine.The study results show that luring the 19 000-hour service time,the martensite structure of S30432 steel has induced or exacerbated further increase of room-temperature tensile strength and hardness besides the precipitated phase enhancement as well as the room-temperature aging embrittlement.Affected by the martensite structure,the tensile impact fracture of S30432 steel at room-temperature is formed along the grain boundary regions close to the martensitic structure rather than along the grain boundary precipitated phase of the intergranular fracture toughness,while at high temperature,the fracture exhibits transgranular dimple fracture.%为评估S30432钢组织中出现马氏体时其长期服役安全性,利用XRD、SEM、TEM、拉伸试验机、冲击试验机和维氏硬度试验机等仪器,对组织中存在马氏体的S30432钢进行了力学性能及其断裂模式的试验研究.结果表明:在19 000 h服役时间内,马氏体组织引起了或加剧了S30432钢室温抗拉强度和硬度在析出相强化基础上的进一步升高和服役室温脆化;受马氏体组织影响,室温下S30432钢的拉伸冲击断裂模式为沿着存在马氏体组织的紧邻晶界区域断裂,而非沿着晶界析出相的沿晶韧窝断裂,高温下S30432钢为穿晶韧窝断裂.