摘要
研究了Q355B热轧H型钢轧后冷却温度880~320℃对H型钢翼缘强度、韧性及组织的影响。结果表明,当控冷后温度为570℃时,钢的屈服强度较空冷工艺提高73 MPa,断后伸长率为23.5%;当控冷后温度为320℃时,钢的屈服强度较空冷工艺提高228 MPa,断后伸长率为16.0%,出现伸长率不合格的情况。Q355B热轧H型钢在轧后正火工艺所得金相组织为铁素体(F)+珠光体(P),铁素体晶粒度为11.0级。当控冷工艺温降速度为73.9℃/s、冷后温度为570℃时,喷水侧翼缘表层出现贝氏体(B),翼缘内侧及心部组织为F+P,晶粒度12.0~12.5级;当控冷温降速度为91.4℃/s,冷后温度为320℃时,喷水侧表层出现马氏体(M),心部及内侧出现贝氏体(B),此时钢的强度过高,塑性严重不足。
Effect of rolling end-cooling temperature 880~320℃of experiment of Q355B hot-rolled H-beam steel on the strength,toughness and structure of the H-beam steel flange is studied.The results show that as the temperature after controlled cooling is 570℃,the yield strength of the steel increases by 73 MPa compared to that of the air cooling process,and the elongation after fracture is 23.5%;as the temperature after controlled cooling is 320℃,the yield strength of the steel increases by 228 MPa compared to that of the air cooling process,and the elongation after fracture is 16.0%,which shows that the elongation rate is not qualified.The microstructure and ferrite grain size of Q355B hot rolled H beam steel obtained by normalizing after rolling are F+P and 11.0.When the temperature drop rate of controlled cooling process is 73.9℃/s and the end-cooling temperature is 570℃,B appears on the surface of the jet flange,the structure of the inner and core of the flange is F+P,and the grain size is 12.0~12.5;as the cooling temperature drop rate is 91.4℃/s,and the end-cooling temperature is 320℃,M appears on the surface at the spraying side,and B appears at the core and inner side,at this time,the strength of steel is too high and the plasticity is seriously insufficient.
作者
徐正彪
王延苹
刘瑞刚
张玉冰
赵任
徐剑
秦哲
Xu Zhengbiao;Wang Yanping;Liu Ruigang;Zhang Yubing;Zhao Ren;Xu Jian;Qin Zhe(Rizhao Steel Holding Group Co Ltd,Rizhao 276806)
出处
《特殊钢》
2022年第2期51-54,共4页
Special Steel
关键词
控制冷却
热轧H型钢
Q355B钢
组织和性能
晶粒细化
Controlled Cooling
Hot Rolled H-Beam Steel
Q355B Steel
Structure and Performance
Grain Refinement
