热轧钛微合金化高强钢低温冲击韧性的控制  

Low temperature impact toughness controlling for Ti-microalloyed high strength steel

作　　者：杨跃标 李宗强 邓深 樊雷 刘清友[3] 赵征志 YANG Yue-biao;LI Zong-qiang;DENG Shen;FAN Lei;LIU Qing-you;ZHAO Zheng-zhi(Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,Beijing,China;Technical Center,Guangxi Liuzhou Iron and Steel Group Company Limited,Liuzhou 545002,Guangxi,China;Institute of Structural Steels,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]北京科技大学钢铁共性技术协同创新中心,北京100083 [2]广西柳州钢铁集团有限公司技术中心,广西柳州545002 [3]钢铁研究总院工程用钢研究所,北京100081

出　　处：《钢铁》2021年第3期41-50,共10页Iron and Steel

基　　金：中组部西部之光访问学者资助项目(2019);广西创新驱动发展专项资金资助项目(桂科AA18242012);广西柳州市科技计划重大专项资金资助项目(2020GACA0401)。

摘　　要：为了解决热轧钛微合金化高强钢低温冲击韧性差的问题,采用光学显微镜、扫描电镜、能谱仪等设备并结合热力学及动力学计算,从冲击断口的形貌、TiN第二相、金相组织方面进了原因分析。分析结果表明,造成试验钢低温冲击韧性差的主要原因为钢中存在大颗粒TiN第二相,钢中珠光体带状组织严重及尺寸分布不均以及两者中大颗粒TiN的影响作用更为显著。通过增加KR铁水脱硫及RH精炼工序,提高连铸二冷强度,降低钢中的碳、氮质量分数等优化措施,减小了大颗粒TiN的尺寸、降低了钢中珠光体带组织等级并提高铁素体等软相组织体积分数和组织均匀性,使钛微合金化高强钢的低温冲击韧性得到了显著改善,合格率提升至100%。To solve the problem of inferior low-temperature impact toughness of hot-rolled titanium microalloyed high-strength steel,the reasons were analyzed from the aspects of impact fracture morphology,second phase of TiN and metallographic structure by means of the optical microscope,the scanning electron microscope,the energy dispersive spectrometer and other devices combined with thermodynamics and kinetics calculation.The analysis results showed that the main reasons for the inferior low-temperature impact toughness of the test steel are as follows.The presence of large particles of the second phase of TiN in steel,serious pearlite banded structure and uneven size distribution in steel,the effect of large TiN particles was more significant.By adding the processes of KR hot metal desulfurization and RH refining,improving the secondary cooling strength of continuous casting,reducing the mass percent of C,N in steel and other optimization measures,and therefore,the size of large TiN particles was reduced,the grade of pearlite banded structure in steel was reduced,as well as the proportion of soft phase structure of ferrite and the microstructure uniformity were increased.The low-temperature impact toughness of hot-rolled titanium microalloyed high-strength steel was improved significantly and the qualified rate was increased to 100%.

关 键 词：钛微合金化 高强钢 低温冲击韧性 TIN 带状组织 

分 类 号：TG142.1[一般工业技术—材料科学与工程]