冷却工艺对Q500qE桥梁钢组织与性能的影响  

Effect of cooling process on microstructure and mechanical property of Q500qE bridge steel

作　　者：武凤娟 杨浩 曲锦波 Wu Fengjuan;Yang Hao;Qu Jinbo(Institute of Research of Iron and Steel,Shagang,Jiangsu Province,Zhangjiagang Jiangsu 215625,China)

机构地区：[1]江苏省(沙钢)钢铁研究院,江苏张家港215625

出　　处：《金属热处理》2023年第6期130-135,共6页Heat Treatment of Metals

摘　　要：以高强度桥梁钢Q500qE为对象,研究不同冷却工艺对其组织和性能的影响规律。研究表明,低速冷却(5℃/s)工艺所得组织以粒状贝氏体为主,M/A岛尺寸粗大,虽然屈强比较低,但强度偏低,韧性较差;高速冷却(25℃/s)工艺所得组织以板条贝氏体为主,M/A岛呈球状或棒状,强度和韧性均得到较大提升,但屈强比偏高;分段冷却(20℃/s+空冷+20℃/s)工艺所得组织为多边形铁素体+板条贝氏体+粒状贝氏体的复合组织,M/A岛细小弥散,屈强比最低,韧性最高,综合性能最佳。Taken high-strength bridge steel Q500qE as the object,the influence of different cooling processes on its microstructure and properties were studied.The results show that under the low speed cooling process(5℃/s),the microstructure mainly consists of granular bainite with coarse M/A islands,which exhibits a low strength and poor toughness,in spite of a low yield ratio.The high speed cooling process(25℃/s)leads to a lath bainite dominant microstructure with spherical and rod-like M/A islands,with a much improved strength and toughness,but a high yield ratio.Upon the interrupted cooling process(20℃/s+air cooling+20℃/s),a multiphase microstructure,containing polygonal ferrite,lath bainite and granular bainite,with fine and dispersed M/A islands,is obtained,which results in the lowest yield ratio,highest toughness,and best overall properties.

关 键 词：Q500qE桥梁钢 冷却工艺 M/A岛 屈强比 低温韧性 

分 类 号：TG142.4[一般工业技术—材料科学与工程]