摘要
采用两阶段控轧控冷技术制备出了800 MPa级贝氏体钢,并通过光学显微镜、透射电镜及硬度检测,对所获贝氏体组织的热稳定性进行了定性研究,观察了试验钢焊接后的接头组织。实验结果表明:在A1温度以下长时间保温过程中,实验用钢的贝氏体组织演化缓慢,表现出了良好的热稳定性。700℃等温20 h后才能形成大量的等轴铁素体,导致硬度值显著降低。此时,在透射电镜下可以观察到贝氏体板条束逐渐合并,内部位错密度也显著降低。试验钢焊接接头组织的观察则显示焊接热影响宽度较小,且晶粒粗化不明显。分析认为此类贝氏体组织的热稳定性与析出相粒子对位错的钉扎作用密切相关。
800 MPa grade baintie steel was prepared by thermo-mechanically controlled processing （TMCP）, and thermal stability of microstructure of the steel was studied by means of optical microscope （OM） , transmission electron microscopy （TEM） and hardness test, and the microstructure of welded joint of the steel was also observed. The results show that during isothermal holding below the transformation temperature Al for long time, the evolution of bainite of the steel is slowly, indicates the thermal stability of the tested steel is excellent. Equiaxed ferrite of the steel is observed after holding at 700 ℃ for 20 h, which results in the decreasing of the hardness. The result of the TEM shows that the laths of bainite gradually begin to merge and the density of dislocations decreases. The width of heat affected zone （HAZ） of the welded joint of the tested steel is narrow and the coarsening of the grain is not evidently. The thermal stability of the tested steel is correlated with the dislocations pinned by second particles.
作者
李敬
杨跃辉
苑少强
褚祥治
LI Jing YANG Yue-hui YUAN Shao-qiang CHU Xiang-zhi(Department of Electromechanical Engineering, Tangshan College, Tangshan 063000, Chin)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2017年第2期125-128,共4页
Transactions of Materials and Heat Treatment
基金
河北省钢铁联合研究基金(E2014105091)
河北省高等学校科学研究项目(QN2014337
ZC2016022)
唐山学院科研基金(13001B)
