回火温度对高氮不锈轴承钢显微组织与力学性能的影响  

Effect of tempering temperature on microstructure and mechanical properties of high nitrogen stainless bearing steel

作　　者：王玲奇[1,2] 何燕霖 潘乐[2] Wang Lingqi;He Yanlin;Pan Le(School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;Shanghai Bearing Technology Research Institute,Shanghai 201801,China)

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]上海市轴承技术研究所,上海201801

出　　处：《金属热处理》2021年第6期8-13,共6页Heat Treatment of Metals

摘　　要：采用万能拉伸试验机、冲击试验机、光学显微镜、XRD、SEM和TEM等对高氮不锈轴承钢Cronidur 30不同回火温度下的显微组织和力学性能进行了研究和分析。结果表明:高氮不锈轴承钢Cronidur 30在150〜500℃回火时的显微组织为回火马氏体+碳氮化物+残留奥氏体,高于550℃回火后基体逐渐转变为回火索氏体,同时析出相逐渐聚集、长大;随着回火温度的升高,强度和硬度总体上呈现先下降后升高再下降的过程,而冲击性能反之,在450℃回火时,碳化物M_(23)C_(6)和氮化物Cr_(2)N析出明显,此时产生二次硬化现象,其抗拉强度可达2133 MPa。400 ℃回火试样发现有极少量富Cr-Fe-Mo的析出相(σ相),显著降低其冲击性能,500 ℃回火时残留奥氏体分解、转变导致冲击性能略有降低。Microstructure and mechanical properties of high nitrogen stainless bearing steel Cronidur 30 with different tempering temperature were studied and analyzed by universal tensile testing machine,impact testing machine,OM,X-ray diffraction,SEM and TEM,etc.The results show that the microstructure is tempered martensite,carbonitride and retained austenite after tempering at 150-500 ℃.When the tempering temperature exceeds 550℃,the microstructure is tempered sorbite,and the precipitated phase gradually gathers and grows.With the tempering temperature increase,the hardness and the tensile strength first decrease,then increase,finally decrease,the impact toughness behaves on the contrary.Secondary hardening occurs because of M_(23)C_(6) and Cr_(2)N increase when tempered at 450℃,and the tensile strength is 2133 MPa.After tempered at 400℃,the precipitated phases(σ phases)which riched in Cr-Fe-Mo is observed slightly,reduces impact toughness observably.When tempered at 500℃,the impact toughness slightly decreases because of the translation of retained austenite.

关 键 词：高氮不锈轴承钢Cronidur 30 回火温度 二次硬化 Σ相 残留奥氏体 性能 

分 类 号：TG1S6.5[金属学及工艺—金属学]