AISI 300系列奥氏体不锈钢渗氮层组织和性能研究  

Organization and Properties of Nitriding Layer for AISI 300 Series Austenitic Stainless Steel

作　　者：孙璐[1,2] 曹驰 杜金涛[1,2] 李元东[1,2] 陈志林[3] SUN Lu;CAO Chi;DU Jin-tao;LI Yuan-dong;CHEN Zhi-lin(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Non-ferrous Metal Alloys and Processing,Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China;Wenzhou Pump and Valve Engineering Research Institute,Lanzhou University of Technology,Zhejiang Wenzhou 325000,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学有色金属合金及加工教育部重点实验室,兰州730050 [3]兰州理工大学温州泵阀工程研究院,浙江温州325000

出　　处：《表面技术》2023年第1期421-431,共11页Surface Technology

基　　金：甘肃省重点研发计划(20YF8GA058)。

摘　　要：目的在AISI 300系列奥氏体不锈钢表面制备单一S相渗氮层,提高该系列不锈钢渗氮层的硬度、抗磨损性能,对比揭示渗氮前后不锈钢的磨损机制。方法采用低温辉光等离子渗氮技术(LTPNT)在AISI 300系列奥氏体不锈钢表面制备渗氮层。利用光学显微镜(OM)、扫描电子显微镜(SEM)、电子探针(EPMA)、X射线衍射仪(XRD)分析渗氮层的截面形貌、元素分布和物相组成;通过比磨损率和磨痕形貌分析渗氮层的摩擦学性能;利用电化学实验考察渗氮前后3种不锈钢的耐蚀性。结果AISI 300系列奥氏体不锈钢经380℃、12 h处理后,其表面获得了厚度为15μm左右、与基体致密结合、组织成分均匀的渗氮层;渗氮层的相结构主要为S相,无CrN相析出;经渗氮后,该系列不锈钢表面硬度均为1100HV左右,较基体硬度提高了5倍左右;不锈钢基体的磨损机理为黏着和磨粒磨损,经渗氮后转变为氧化磨损和微切削;渗氮层的比磨损率约为不锈钢基体的1/20,抗磨损的能力得到显著提升;在25℃环境温度下渗氮后,304L、316L和321的自腐蚀电位下降,腐蚀电流密度增加,腐蚀速率加快,耐腐蚀性能稍有降低。通过对比腐蚀形貌发现,渗氮层仍具有一定的耐蚀性能。结论通过LTPNT可以获得高硬度、组织均匀致密、结合强度高的渗氮层,渗氮层中S相的存在可以显著提高AISI300系列奥氏体不锈钢的表面硬度、抗磨损能力,降低其摩擦因数和比磨损率,对延长不锈钢的服役寿命有着积极的作用。This advanced surface strengthening technology can improve the anti-wearing properties of stainless steel without altering the original material properties of the matrix.The work aims to prepare a single S-phase nitriding layer on the surface of AISI 300 series austenitic stainless steel by low-temperature plasma nitriding technology(LTPNT)to improve the hardness and anti-wearing properties of stainless steel and compare the wear mechanisms of stainless steel before and after nitriding.The effect of the nitriding layer on the hardness,anti-wearing properties,and wear mechanism of stainless steel was investigated.Three widely used Cr-Ni commercial steels(AISI 304L,AISI 316L,and AISI 321)were sliced into 15 mm×15 mm×5 mm rectangular cubes,which were mechanically ground and polished.Nitrided samples at 380℃for 12 hours were the major process parameters for LTPNT.The nitrided samples were mechanically polished and etched with marble mordents(Cu2SO4+HCl+distilled water).A metallographic microscope(AxioCam MRc5 ZEISS)was used to observe the cross-sectional morphology of the nitrided samples.The elemental distribution and phase composition of the nitriding layer were analyzed by EPMA and XRD(D/max-2400).The tribological properties of nitriding layer were characterized by specific wear rate and corrosion morphology.The wear microstructures of the samples were observed by a scanning electron microscope(QUATA FEG450).The corrosion resistance of samples was evaluated by an electrochemical experiment(CHI600E electrochemical workstation).In addition,wear tests were performed on material surface with performance comprehensive tester(CFT-I),and the surface and cross-sectional hardness were measured with a vicker microhardness meter(MVC-1000JMT1).The nitriding layer was uniform and dense,with a thickness of 15μm approximately.The primary phase of the nitriding layer was the S-phase,but the Cr-N phase was not precipitated in the layer,indicating that nitriding did not deteriorate the corrosion resistance of the steel matrix.

关 键 词：低温辉光等离子渗氮技术 渗氮层 奥氏体不锈钢 抗磨损性 硬度 S相 

分 类 号：TG142.1[一般工业技术—材料科学与工程]