待温厚度对一种Mn系HSLA钢组织及强韧性的影响  

Effect of thickness at holding temperature on microstructure,strength and toughness of a Mn based HSLA steel

作　　者：孙震 高朋 刘振宇[3] SUN Zhen;GAO Peng;LIU Zhen-yu(Zhanjiang Iron and Steel Co.,Ltd.,Baosteel,Zhanjiang 524000,China;School of Mechanical and Intelligent Manufacturing,Jiujiang University,Jiujiang 332005,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)

机构地区：[1]宝钢湛江钢铁有限公司,广东湛江524000 [2]九江学院机械与智能制造学院,江西九江332005 [3]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《塑性工程学报》2021年第8期161-168,共8页Journal of Plasticity Engineering

基　　金：广东省促进经济高质量发展专项资金海洋经济发展项目(GDOE[2019]A08)。

摘　　要：对Mn系微合金高强钢进行了不同中间坯待温厚度的轧制实验,并通过室温拉伸实验、摆锤冲击实验、透射电镜和扫描电镜研究了不同的中间坯待温厚度对实验钢的相组成、晶粒尺寸、晶界特性的演变及其对低温韧性的影响规律。结果表明,随着中间坯待温厚度的增加,实验钢的屈服强度、抗拉强度、伸长率和低温冲击韧性均得到了有效改善,韧脆转变温度降低约20%。待温厚度的增加促进了精轧过程中实验钢组织中变形带的产生,增加了相变过程中晶粒的形核点,有效晶粒尺寸细化约12%;同时,变形带也阻碍了贝氏体板条的生长,促进了多边形铁素体、针状铁素体等相变产物的形成,使大角度晶界的比例显著提高35%,有效地抑制了微裂纹的传播,最终使实验钢低温韧性明显改善。The rolling experiments of Mn based microalloyed high strength steel with different thicknesses at holding temperature were carried out,and the effects of different thicknesses at holding temperature on the phase composition,grain size,grain boundary characteristics and low temperature toughness of experimental steel were studied by room temperature tensile test,pendulum impact test,transmission electron microscope and scanning electron microscope.The results show that the yield strength,tensile strength,elongation and low temperature impact toughness of experimental steel are effectively improved with the increase of the thickness at holding temperature of the intermediate billet,and the ductile brittle transition temperature is reduced by about 20%.The increase of the thickness at holding temperature promotes the formation of deformation band in the microstructure of experimental steel during the finishing rolling process,increases the nucleation points of the grain during the phase transformation process,and the effective grain size is refined by about 12%.At the same time,the deformation band also hinderes the growth of bainite lath and promotes the formation of polygonal ferrite,acicular ferrite and other phase transformation products.The proportion of large angle grain boundary is increased by 35%,which effectively restrains the propagation of microcracks,and finally apparently improves the low temperature toughness of experimental steel.

关 键 词：HSLA钢 待温厚度 组织细化 低温韧性 

分 类 号：TG335.11[金属学及工艺—金属压力加工]