摘要
为研究轴承钢GCr15连铸和热轧过程中组织遗传对产品性能的影响,取含Ni轴承钢GCr15连铸坯、热轧中间坯和热轧宽钢带试样,采用金相显微镜、扫描电镜和拉伸试验机等手段,分别研究了边部、1/4处和中部试样的低倍组织、显微组织、晶粒度级别、元素含量和力学性能,并观察了钢带拉伸断口形貌。结果表明,铸坯经轧制到热轧中间坯再到热轧钢带过程存在晶粒大小和显微组织遗传,钢带力学性能受到了遗传的影响。GCr15钢铸坯低倍组织致密,疏松级别为0.5级,无角裂和边裂;电磁搅拌圈痕外组织致密,圈内相对疏松。热轧中间坯和钢带从边部、1/4处到中部组织逐渐粗化、片层状珠光体趋于明显,中间坯晶粒度从2.5级、2.0级到1.5级,钢带晶粒度从12级、11级到10.5级。碳和铬在中间坯中间部位偏聚,中部碳偏析指数相对于均值为1.02,而相对于边部为1.04。钢带边部强度较高,抗拉强度R_(m)、屈服强度R_(p0.2)分别高出1/4处和中部约200、250 MPa。钢带不同位置断口都呈现为韧性断裂,1/4处试样的韧性优于边部和中部位置。
In order to study the effect of structure heredity on product property during the continuous casting and hot rolling process of bearing steel GCrl5,the samples acquired from the continuous casting billet,the hot rolled inter-mediate billet and the hot rolled wide steel strip in bearing steel GCrl5 with Ni were tested by the ways of metallo-graphic microscope,scanning electron microscope and tensile testing machine,etc.The low-powered structure,mi-crostructure,grain size level,element content and mechanical property from the edge,quarter and middle parts were compared respectively,and the tensile fractures of steel strip were observed.The results show that the grain size and microscopic structure heredity exists in the process of rolling the casting billet into the hot rolled steel strip through the hot rolled intermediate billet,which affects mechanical properties of the steel strip.The macrostructure is compact,the level of loose is 0.5,and there is no crack in the corner and edge for low-powered billet of steel GCrl5.The microstructure outside the circular mark of electromagnetic stirring is compact,however,which is loose relatively within the circular mark.The microstructure of hot rolled intermediate billet and steel strip become coarsening from the edge to the middle after the quarter,and the lamellar layer pearlite become more obvious.The grain size grade of intermediate billet is from 2.5 to 1.5 after 2.0,and which of steel strip is from 12 to 10.5 after 1l.The element of carbon and chromium segregate in the middle of intermediate billet,and the index of carbon seg-regation in the middle is 1.02 relative to the average value,but which is 1.04 contrasted to the value of edge.The mechanical strength of the edge of steel strip is higher,and the tensile strength Rm and the yield strength Rpo.2 is 200 MPa,250 MPa higher than the quarter and the middle of steel strip respectively.The morphology of fracture in different positions show ductile fracture,and the ductility of the sample in quarter is better than in e
作者
朱施利
裘韶均
贾国军
张本亮
吴红翔
杨志强
ZHU Shili;QIU Shaojun;JIA Guojun;ZHANG Benliang;WU Hongxiang;YANG Zhiqiang(Technology Center,Ningbo Iron&Steel Co.,Ltd.,Ningbo 315807,Zhejiang,China)
出处
《连铸》
北大核心
2024年第4期47-51,76,共6页
Continuous Casting
基金
宁波市重大科技任务攻关资助项目(2022Z105)。
关键词
轴承钢GCr15
宽钢带
铸轧
组织
遗传
性能
bearing steel GCrl5
wide steel strip
casting and rolling
structure
heredity
property
