热处理对42CrMo钢的耐延迟断裂性能的影响  

EFFECT OF HEAT TREATMENT ON DELAYED FRACTURE RESISTANCE OF STRUCTURAL STEEL 42CrMo

作　　者：王毛球[1] 董 瀚[1] 惠卫军[1] 陈思联[1] 翁宇庆[2] 

机构地区：[1]钢铁研究总院,北京100081 [2]中国金属学会,北京100711

出　　处：《金属学报》2002年第7期715-719,共5页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展规划资助项目 G1998061503

摘　　要：对42CrMo钢进行了淬火回火处理和等温淬火处理,探讨热处理工艺对高强度钢的耐延迟断裂性能的影响.缺口拉伸实验表明,与淬火回火相比,等温处理后42CrMo钢在抗拉强度为1500 MPa级时具有优良的耐延迟断裂性能.组织观察发现,42CrMo钢等温处理后由下贝氏体组成,ε-碳化物分布在贝氏体板条内部,原奥氏体晶界无碳化物,因而耐延迟断裂性能较好.随等温温度的降低,贝氏体板条变细,强度增加,耐延迟断裂性能也提高.可见,通过等温处理获得下贝氏体组织是改善1500MPa级合金结构钢的耐延迟断裂性能的一种有效途径.To investigate the effect of heat treatment on delayed fracture resistance of high strength structural steel, the steel 42CrMo was quenched and tempered and isothermally quenched, respectively. Tensile results of notch specimens in acid solution show that compared with quenching and tempering, isothermal quenching brought 42CrMo has higher delayed fracture resistance when it was treated to a high tensile strength of about 1500 MPa. Microstructural. observation shows that the isothermally quenched 42CrMo is mainly composed of bainitic laths with epsilon-carbides distributed in them and without carbides along the prior austenite grain boundaries, which is suggested to cause the improvement in delayed fracture resistance. With the decrease of isothermal temperature, the bainitic lath becomes finer, resulting in an increase of strength and delayed fracture resistance. It can be concluded that isothermal quenching is an effective way to overcome delayed fracture of 1500 MPa level high strength steel.

关 键 词：等温处理 贝氏体 延迟断裂 

分 类 号：TG142.1[一般工业技术—材料科学与工程]