中文摘要：

研究了不同Ti含量对微合金钢的力学性能的影响规律,并采用Hall-Petch细晶强化公式和Ashby-Orowan沉淀强化模型分析其变化规律的原因。结果表明：含Ti微合金低碳钢随着钢中Ti含量的增加,钢材的屈服强度、抗拉强度、屈强比都有不同程度的增加,且以Ti含量为0.042%为界,屈服强度和抗拉强度的增长趋势显著增加,主要是因为Ti含量大于0.042%时,富余的Ti与C元素结合析出颗粒细小的Ti C颗粒,起到强烈的沉淀强化作用;伸长率随Ti含量的增加减小,其降低的程度也随Ti含量减小,原因是Ti含量较低时析出的Ti N、Ti4C2S2尺寸较大,引起的脆化效应要远强于Ti C。Ti C颗粒的沉淀强化作用使试验钢强度显著增加,伸长率略有下降。

英文摘要：

Influence of different Ti content on mechanical properties of micro-alloyed steel was studied. The Hall-Petch grain refinement formula and Ashby-Orowan precipitation strengthening model were carried out to analyze the reason for the variation. The results show that the yield strength,tensile strength and the yield ratio increase in varying degrees with the increasing of Ti content in micro-alloyed steel.Besides,the growth trend of yield strength and tensile strength increase rapidly when Ti content is beyond 0. 042%. The reason for this is that,the abundant Ti in combination with C dissolves out fine particles of Ti C,which plays a strong effect on precipitation strengthening when Ti content is beyond 0. 042%. Elogation rate decreases with the increasing of Ti content,and its declining trend also decreases as the Ti content increases,which is due to that larger size of precipitated particle of Ti N and Ti4C2S2,and the stronger the embrittlement effects than that of Ti C when the Ti content is lower. On account of the embrittlement effect of Ti C,the strength of steel increases dramatically and its elongation rate decreases slightly.