摘要
利用光学显微镜、透射电子显微镜(TEM)、EDS能谱分析仪和拉伸冲击试验机,研究了轧后不同驰豫时间对500 MPa高强度桥梁钢微观组织结构、第二相析出及力学性能的影响。结果表明:轧后弛豫有利于贝氏体晶粒的细化,并可获得粒状贝氏体和板条贝氏体双相组织,随着轧后驰豫时间的延长,板条贝氏体减少,抗拉强度下降,粒状贝氏体的出现、增多、长大的过程,屈服强度先上升后下降。同时轧后弛豫也有利于第二相析出,随着弛豫时间的延长,第二相析出越充分,析出物不断聚集长大。当轧后驰豫时间在(60~80)s,然后以20℃/s的速度冷却至400℃,可以获得良好的综合力学性能,性能满足Q500qE标准要求。
Effect on microstructure,the second phase precipitation and mechanical property of 500 MPa high-strength bridge steel by relaxation after finish rolling is studied by optical microscope,transmission electron microscope,EDS energy spectrum analyzer and tensile impact testing machine.The results showed:relaxation after finish rolling is good for refinement of Bainite grains,and the dual-phase microstructure of granular Bainite and lath Bainite can be obtained,the lath Bainite increases along with the extension of the relaxation time after rolling,the tensile strength decreases,the granular Bainite appears,increases and grows up,the yield strength increases first and then decreases.At the same time,relaxation after finish rolling is good for the second phase precipitation,the second phase can be fully precipitated along with the extension of relaxation time after finish rolling,precipitates keeps gathering and growing up.When the relaxation time after finish rolling is in the range of(60~80)s,it shall be cooled down to 400℃at 20℃/s speed,therefore good comprehensive mechanical property can be obtained,its performance can meet the requirement of Q500qE.
作者
余宏伟
董中波
吴开明
陈英
鲍海燕
YU Hong-wei;DONG Zhong-bo;WU Kai-ming;CHEN Ying;BAO Hai-yan(The State Key Laboratory of Refractory and Metallurgy,Wuhan University of Science and Technology,Wuhan,Hubei 430080,China;Wuhan Iron&Steel Group Echeng Iron&Steel Co.,Ltd.,Ezhou,Hubei 436002,China;Baosteel Central Research Institute,Wuhan,Hubei 430080,China)
出处
《云南冶金》
2021年第4期77-82,共6页
Yunnan Metallurgy
基金
国家自然科学基金联合基金重点项目(U20A20279)。
关键词
高强度桥梁钢
驰豫
组织
性能
high-strength bridge steel
relaxation
organization
performance
