摘要
分析了SWRH82B拉拔尖杯断口的宏观形貌及径向碳含量、低倍、金相组织,结果发现碳含量极差最大达到0.033%;经过直径的纵剖平面存在多处人字裂纹,裂纹附近有严重网状渗碳体组织。分析认为:尖杯状断口形成的直接原因是心部单元体金属存在塑性流变不连续,发生位错塞积,产生应力集中,通过萌生裂纹的方式实现局部应变;根本原因是连铸坯碳偏析使盘条心部存在网状渗碳体,塑性降低,脆性增加所致。在炼钢和轧钢工序实施一系列改进措施后,网状渗碳体得到有效控制,拉拔断丝发生率明显降低。
The macro-morphology,radial carbon content,macrostructure and macrostructure of SWRH82B drawing cup fracture were analyzed.The results show that the maximum range of carbon content is 0.033%;there are many herringbone cracks in the longitudinal section,and there is serious network cementite near the cracks.The analysis shows that the direct reason is that the metal plastic flow discontinuity of the central unit leads to dislocation accumulation and stress concentration,and the local strain is realized by the way of crack initiation;the basic reason is that the carbon segregation of the continuous casting slab causes the existence of net cementite in the core of the wire rod,which reduces the plasticity and increases the brittleness.After a series of improvement measures have been taken in steel-making and rolling processes,the network cementite has been effectively controlled and the rate of wire breaking in drawing has been significantly reduced.
作者
王海宾
Wang Haibin(Technology Center of HBIS Group Xuansteel Company, Xuanhua, Hebei,075100;Hebei Engineering Research Center for Steel Structures, Xuanhua, Hebei, 075100)
出处
《河北冶金》
2020年第5期26-30,共5页
Hebei Metallurgy
