摘要
采用双真空熔炼制备了8Cr4Mo4VE轴承钢并对其进行均匀化处理,以控制其碳化物的数量、大小、形态及分布。利用旋转弯曲疲劳试验测试了8Cr4Mo4VE轴承钢的旋弯疲劳性能,采用扫描电镜、体式显微镜和能谱仪等分析了其旋弯疲劳试样的断口形貌和起裂源成分。结果表明:8Cr4Mo4VE轴承钢疲劳极限达到915 MPa。断口观察表明,其疲劳损坏方式主要有表面起裂和次表面碳化物起裂。次表面碳化物起裂扩展模式有3种:碳化物起裂快速扩展断裂、碳化物起裂扩展形成鱼眼区(FIE)、碳化物萌生微裂纹形成光学黑区(Optical dark area,ODA)后扩展形成鱼眼区。碳化物周围萌生裂纹及扩展时其扩展速率da/dN同应力强度因子ΔK满足Forman公式。碳化物应力强度因子ΔK_(carb)远小于光学黑区应力强度因子ΔK_(ODA)时,碳化物周围出现ODA,其裂纹扩展速率约为(1.84~2.10)×10^(-12) m/cycle。8Cr4Mo4VE轴承钢中的碳化物形状及所受应力对其疲劳寿命循环次数具有显著影响。
8Cr4Mo4VE bearing steel was prepared by double vacuum melting and homogenized to control the quantity,size,morphology and distribution of carbides.The rotating bar bending fatigue properties of the 8Cr4Mo4VE bearing steel were tested by rotating bar bending fatigue test.The fracture surface morphology and crack initiation source composition of the rotating bar bending fatigue sample were analyzed by scanning electron microscopy,body microscope and energy dispersive spectrometer analysis.The results show that the fatigue limit of the 8Cr4Mo4VE bearing steel reaches 915 MPa.The fracture observation shows that the main fatigue damage modes of the steel are surface cracking and subsurface carbide cracking.There are three modes of crack initiation and propagation at the subsurface carbide:carbide initiation and rapid propagation fracture,carbide initiation and propagation to form fish-in-eye(FIE),and carbide initiation and micro-crack to form optical dark area(ODA)and then propagation to form FIE.When the crack is initiated and propagated around the carbide,the propagation rate da/dN and the stress intensity factorΔK meet the Forman formula.When the carbide stress intensity factorΔK_(carb) is much smaller than the optical dark area stress intensity factorΔK_(ODA),ODA appears around the carbide,and the crack growth rate is about(1.84-2.10)×10^(-12) m/cycle.The shape and stress of carbides in the 8Cr4Mo4VE bearing steel have a significant effect on the cycles times of fatigue life.
作者
赵开礼
童锐
罗志强
张强
李建新
杨卯生
孙勇
ZHAO Kai-li;TONG Rui;LUO Zhi-qiang;ZHANG Qiang;LI Jian-xin;YANG Mao-sheng;SUN Yong(Research and Development Cente,Air China in Harbin Bearing Co Ltd,Harbin 150028,China;Institute of Special Steel,Central Iron and Steel Research Institute,Beijing 100081,China;Technology Center Departement,Fushun Special Steel Shares Co Ltd,Fushun 113006,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2022年第6期137-146,共10页
Transactions of Materials and Heat Treatment
作者简介
赵开礼(1961-),男,高级工程师,本科,主要从事航空轴承钢研究,电话:0451-56891175,E-mail:yanmei1963@163.com;通信作者:杨卯生(1963-),男,教授,博士,主要从事高性能轴承齿轮钢研究,E-mail:mshyang@sina.com。
