钙镁复合变质剂对冷轧高强钢组织遗传性及塑性影响  

Effect of Ca-Mg compound modifier on microstructure and plasicity in cold-rolled high strength steel

作　　者：李媛媛[1] 甄维静 李永亮 闫志杰 Li Yuanyuan;Zhen Weijing;Li Yongliang;Yan Zhijie(Tangshan Vocational College of Science and Technology,Tangshan 063001,Hebei,China;Thchnology Center of Tangshan Steel,Hebei Steel Group,Tangshan 063016,Hebei,China;School of Material Science and Engineering,North University of China,Taiyuan 030051,Shanxi,China)

机构地区：[1]唐山科技职业技术学院,河北唐山063001 [2]河钢唐钢技术中心,河北唐山063016 [3]中北大学材料科学与工程学院,山西太原030051

出　　处：《钢铁钒钛》2021年第1期119-125,共7页Iron Steel Vanadium Titanium

基　　金：中央引导地方科技发展专项资金项目(YDZX20191400004587)。

摘　　要：利用光学显微镜(OM)、透射电镜(TEM)和电子背散射衍射(EBSD)等设备研究了Ca-Mg复合变质剂对冷轧超高强钢铸坯中TiN粒子析出的影响机制,并对显微组织在各工序的遗传性及塑性改善进行了系统对比。结果发现:添加变质剂以后,铸坯中TiN第二相粒子尺寸明显变小,数量增多,分布更弥散;添加改质剂后钢坯、热轧钢板中沿晶界铁素体减少,冷轧退火后显微组织变细;与未添加变质剂试验钢比,屈服强度和屈强比提高,材料折弯、扩孔率得到改善。变质剂的添加改变了钢液中TiN形核机制。弥散的TiN可以细化铸态组织,并通过遗传效应对热轧、冷轧连退组织产生影响,改善力学性能和成型性能。The influence mechanism of Ca-Mg compound modifier on TiN precipitation in ingot of producing ultra-high cold-rolled strength steel were studied by means of optical microscope(OM), transmission electron microscope(TEM) and electron backscatter diffraction(EBSD), etc. Andmicrostructure hereditary effect and plastic improvement at various process steps were compared systematically.The result showed that the size of TiN reduced with the addition of modifier, whereas its density increased with a relatively uniform distribution. Addition of modifier decreased the volume fraction of ferrite along grain boundary for both ingot and hot rolled strip, and resulted in fine microstructure in the as-cold rolled sheet. Comparing modifier-free sample, the yield strength, yield ratio dramatically increased and the bending properties and hole expanding ratio improved for the modifier-bearing sheet.The nucleation mechanism of TiN was changed by the addition of Ca-Mg compound modifier. The dispersed TiN particles could effectively refine the casting microstructure, and the microstructure for hotrolled or cold-rolled were all refined effectively by hereditary effect which could significantly improve the mechanical properties and formability of steel.

关 键 词：高强钢 TIN 变质剂 显微组织 力学性能 成型性能 

分 类 号：TF76[冶金工程—钢铁冶金]