1.0GPa级I&QP钢组织调控及增强增塑性机制  

Microstructural control and mechanisms of strength-ductility enhancement for 1.0 GPa grade I&QP steel

作　　者：侯晓英 孙卫华 王业勤 金光宇 曹光明 任东 HOU Xiao-ying;SUN Wei-hua;WANG Ye-qin;JIN Guang-yu;CAO Guang-ming;REN Dong(Shandong Iron and Steel Group Rizhao Co.,Ltd.,Rizhao 276805,Shandong,China)

机构地区：[1]山东钢铁集团日照有限公司,山东日照276805

出　　处：《钢铁》2021年第2期132-138,146,共8页Iron and Steel

基　　金：山东省重点研发计划资助项目(2019TSLH0103)。

摘　　要：为研究1.0GPa级I&QP钢的微观形貌特征及增强增塑机制,采用不同退火工艺制度并分析其组织性能特征及其对强塑性的影响。结果表明,将热轧初始组织调控为体积分数不小于85%且晶粒尺寸细小(3~5μm)的针状贝氏体组织,经过I&QP工艺处理后,易于将最终微观组织调控为大于70%的不同位向存在的"板条簇"贝氏体组织、少量晶粒尺寸小于2.5μm的铁素体以及不小于14.5%的片层状残余奥氏体三相混合组织。临界区加热温度适当降低到850℃后,I&QP钢晶粒细化,同时大角度晶界所占比例增加至60.2%,在相变、细晶、析出和位错综合增强增塑机制作用下,抗拉强度大于1.0GPa,强塑积达到30.2GPa·%,同时扩孔率达到62%。In order to investigate the microscopic morphological characteristics and the mechanisms of strength-ductility enhancement of I&QP steel,the characteristics for microstructures and mechanical properties and the effect on strength and plasticity were analyzed by using different annealing processes.The results indicated that the final mixed microstructure was controlled which was composed of "lath-shaped clusters" bainites with different orientations,a small amount of ferrite whose grain size was less than 2.5μm,as well as lamellar retained austenites,when the needle-like bainite was controlled for the initial hot-rolled microstructure,whose volume percent was more than 85% and fine grain size was in the range of 3-5μm.The volume pecent of "lath-shaped clusters" bainites was more than 70%,and the volume percent of lamellar retained austenites was more than 14.5%.When the intercritical heating temperature was decreased to 850℃ properly,the grain size of I&QP steel could be refined obviously,and the ratio of large misorientation angle was increased to 60.2%.Under the combined action for the mechanisms of strength-ductility enhancement which including the phase transformation,grain refinement,phase precipitation and dislocations,the tensile strength was more than 1.0 GPa,the product of tensile strength and ductility was reached to30.2 GPa·%,and the expanding rate was up to 62%.

关 键 词：1.0GPa级高强钢 I&QP工艺 初始热轧组织 增强增塑机制 微观组织调控 

分 类 号：U465.11[一般工业技术—材料科学与工程] TG142.1[机械工程—车辆工程]