等离子淬火对PCrNi3Mo钢拉伸性能的影响  

Effect of plasma quenching on tensile properties of PCrNi3Mo steel

作　　者：罗天放 陈荣刚 吴斌 LUO Tian-fang;CHEN Rong-gang;WU Bin(Department of Mechanical Engineering,Army Artillery Air Defense Academy,Hefei 230031,China)

机构地区：[1]陆军炮兵防空兵学院机械工程系,安徽合肥230031

出　　处：《材料热处理学报》2018年第12期64-70,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51475471)

摘　　要：为提高PCrNi3Mo钢的抗拉伸性能,采用等离子表面淬火技术对其进行表面处理。使用MTS拉伸试验机对PCrNi3Mo钢等离子淬火前后的拉伸性能进行对比分析,并对其在相同应变速率下得到的应力—应变曲线进行比较;使用X射线衍射仪对PCrNi3Mo炮钢表面的残余应力进行检测,使用光学显微镜观察其淬火后硬化区域的组织与形貌。结果表明:等离子淬火后PCrNi3Mo钢拉伸试样的屈服强度、拉伸强度比原始试样分别提高了27.3%和28.6%,断面收缩率、断后伸长率则下降了76.4%和69.4%;原始PCrNi3Mo钢试样断口处有明显的颈缩现象,为韧性断裂,而淬火试样韧性有明显提高但塑性变形能力下降;试样经过等离子淬火后表面由拉应力(496.9 MPa)转变为压应力(-942.2 MPa);淬火试样断面形成月牙形硬化带,月牙内部细密的马氏体组织代替了机体粗大的铁素体组织;淬火后形成的硬化层越深,炮钢材料抗拉强度越高。In order to improve the tensile properties of PCrNi3Mo steel,plasma surface quenching technique was used to treat its surface. The tensile properties of the PCrNi3Mo steel before and after plasma quenching were investigated by using MTS tensile tester,and the stress-strain curves obtained at the same strain rate were compared.The residual stress on the surface of the PCrNi3Mo steel was measured by X-ray diffractometer,and the microstructure and morphology of hardened area after quenching were observed by optical microscope. The results show that the yield strength and tensile strength of the PCrNi3Mo steel after plasma quenching increase by 27.3% and 28.6%,respectively,and the section shrinkage and elongation after fracture decrease by 76.4% and 69.4%,respectively.The fracture surface of the original PCrNi3Mo steel sample shows obvious necking phenomenon,which is ductile fracture,and the toughness of the quenched PCrNi3Mo steel sample is obviously improved but the plastic deformation ability decreases;the surface stress of the sample changes from tensile stress (496.9 MPa)to compressive stress (-942.2 MPa)after plasma quenching;the section of the quenched sample forms crescent-shaped hardening belt,and the fine martensite structure in the crescent replaces the coarse ferrite structure.The deeper the hardened layer formed after quenching is,the higher the tensile strength of the steel is.

关 键 词：等离子淬火 PCrNi3Mo炮钢 拉伸性能 残余应力 显微组织 

分 类 号：TG142.4[一般工业技术—材料科学与工程]