回火工艺对900 MPa级热轧卷板组织与性能的影响  

Effect of tempering process on microstructure and mechanical properties of 900 MPa grade hot rolled steel

作　　者：刘旭辉[1] 曾斌[1] 梁亮[1] 李昭东[2] LIU Xu-hui;ZENG Bin;LIANG Liang;LI Zhao-dong(Technical Center,Hunan Valin Lianyuan Iron and Steel Co.,Ltd.,Loudi 417009,Hunan,China;Department of Engineering Steels,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]湖南华菱涟源钢铁有限公司技术中心,湖南娄底417009 [2]钢铁研究总院工程用钢研究所,北京100081

出　　处：《钢铁》2018年第10期74-78,共5页Iron and Steel

基　　金：国家重点基础研究发展(973)计划资助项目(2015CB654803)

摘　　要：随着轻量化要求的进一步提高,屈服强度900 MPa级高强度钢在工程机械、汽车等领域逐步得到推广应用。与基于相变强化的传统调质生产工艺不同,采用TMCP＋回火工艺开发析出强化型900 MPa级铁素体钢板,着重研究回火工艺对热轧卷板显微组织与力学性能的影响。结果表明,热轧卷板经550-650℃回火热处理后,强度、硬度和冲击韧性显著提高,断后伸长率变化不大;经650-700℃回火热处理后,强度和硬度大幅度降低。热轧卷板的基体组织为细晶准多边形铁素体组织,经回火热处理后,平均晶粒尺寸增大,热轧晶粒尺寸越细小,长大越明显。550-650℃回火促使纳米钛钒碳化物进一步析出是回火钢板强度和硬度提高的主要原因;700℃回火时铁素体晶界出现了数百纳米至1μm的渗碳体颗粒,纳米钛钒钼碳化物减少,降低了沉淀强化作用,铁素体晶粒也粗化,导致了强度下降。Yield strength 900 MPa grade high strength steel gradually used in the construction machinery, automobiles and other vehicles. Differently from the 900 MPa grade steel by traditional production process and strengthening mechanism, the Ti-V alloyed 900 MPa grade steel produced by TMCP process was used as the raw material. By experiment different heat treatment processes, the effects of microstructure and mechanical properties were studied. The results show that the elongation rate of the steel sheet is not changed greatly after the tempering heat treatment, and the impact toughness is obviously improved. The strength and hardness are obviously improved from 550 to 650 v, but they decline obviously between 650 and 700 ℃. On the microstructure aspect, there is no significant change was observed, but a part of ferrite grains grew. The solid solution Ti, V, Mo elements in hot rolled materials continue to precipitate in the form of （Ti, Nb, Mo）C, resulting in precipitation hardening, at 700 ℃ high temperature, the coarse carbides were formed.

关 键 词：超高强钢 钛微合金 析出强化 回火 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156.5[金属学及工艺—金属材料]