感应加热工艺对大规格球扁钢低温韧性的影响
Effect of induction heating process on low temperature toughness of large size bulb flat steel
梁丰瑞 1苏航 1柴锋 1罗小兵 1师仲然 1周乃鹏 1祁震1
作者信息
- 1. 钢铁研究总院有限公司工程用钢研究院,北京 100081
- 折叠
摘要
采用OM、SEM、EBSD、TEM等方法对比研究了不同热处理工艺对大规格球扁钢力学性能及显微组织的影响规律.结果表明,与热轧+回火工艺相比,采用感应淬火+回火工艺时大规格球扁钢球头心部位置-40℃冲击吸收能量提高约112 J,裂纹扩展功提高约125 J,动态撕裂能及断口纤维率均显著提高,韧脆转变温度由约10℃降低至-60℃以下.经感应淬火+回火后,球扁钢球头心部位置的组织为铁素体+马氏体+贝氏体的混合组织,平均晶粒尺寸与热轧+回火工艺相比显著细化,碳化物的数量更多、尺寸更加细小.热轧+回火后冲击断口的微裂纹在珠光体和铁素体晶界上的碳化物处形成,而感应淬火+回火后,冲击断口呈现为具有明显韧窝的韧性断裂特征.同热轧+回火工艺相比,采用感应淬火+回火工艺大大改善了大规格球扁钢的低温韧性.
Abstract
Effects of different heat treatment processes on mechanical properties and microstructure of large size bulb flat steel were researched by means of OM,SEM,EBSD,TEM and other methods.The results show that compared with the hot rolling and tempering process,the impact absorbed energy at-40 ℃ at ball head center of the bulb flat steel after induction quenching and tempering process is increased by about 112 J,the crack propagation work is increased by about 125 J,the dynamic tearing energy and the fracture fiber ratio are significantly increased,and the ductile-brittle transition temperature is reduced from about 10 ℃ to below-60 ℃.After induction quenching and tempering process,the microstructure at ball head center of the bulb flat steel is ferrite+martensite+bainite,of which average grain size is significantly refined compared with the hot rolling and tempering process,and the number of carbides is more and the size is smaller.After hot rolling and tempering process,the microcracks on impact fracture are formed at the carbides on the pearlite and ferrite grain boundaries,while after induction quenching and tempering process,the impact fracture are characterized by ductile fracture with obvious dimples.Compared with the hot rolling and tempering process,the induction quenching and tempering process greatly improves the low temperature toughness of the large size bulb flat steel.
关键词
大规格球扁钢/感应淬火/低温韧性/晶粒尺寸/显微组织Key words
large size bulb flat steel/induction quenching/low-temperature toughness/grain size/microstructure引用本文复制引用
出版年
2024
NETL
NSTL
万方数据