【摘要】 Q&P(Quenching andPartitioning,淬火配分)工艺在CCE条件下,通过采用M_s和M_f点之间的最佳淬火温度和低于M_s点的配分温度,避免配分阶段的贝氏体形成最终可以得到最高含量的残余奥氏体组织。但试验中得到不足体积分数8%的残余奥氏体含量限制了钢塑性的提高。通过提出淬火-贝氏体区配分工艺,并应用在(0.21~0.29)C-(1.5~2.0)Si-(1.5~2.1)Mn成分钢,得到了体积分数12%左右的残余奥氏体含量和25%左右的伸长率,同时强度保持在1 000~1 100 MPa,强塑积最高达到36.6 GPa·%。不同的淬火温度和配分温度试验结果表明,工艺变化对强度影响较低,伸长率和强塑积随着配分温度的提高而提高,其中270℃的淬火温度试样的提高幅度高于245℃淬火试样,采用Q&PB工艺得到了无碳贝氏体+马氏体+残余奥氏体的三相组织。淬火和贝氏体区配分得到了优异的强度和塑性的结合,为新一代汽车用钢的发展提供新的思路。更多还原

【Abstract】 Quenching and partitioning process depends on an optimum quenching temperature and a partitioning temperature between martensite start temperature and martensite finish temperature to avoid bainite transformation during partitioning stage,the highest austenite volume fraction can be obtained under this condition and constrained carbon equilibrium(CCE) model.However,retained austenite fraction obtained by practical experiments is no more than 8%,which limited plasticity improvement.Partitioning in bainite zone(Q&PB) after quenching from austenite was proposed and used on(0.21-0.29)C-(1.5-2.0)Si-(1.5-2.1)Mn steel,25%elongation and 12.3%retained austenite volume fraction was gotten using Q&PB process with tensile strength of 1 000-1 100 MPa,the highest product of stiengfli and ductility was 36.6 GPa-%.The results of quenching temperature and partitioning temperature tests show that:the strength is little effected by temperature,elongation and product of strength and ductility are increased with partitioning temperature,and the increasing rate of 270 ℃quenching sample is higher than that of 245 ℃ quenching sample.An excellent combination of strength and elongation is realized using novel Q&PB process,which can provide a new idea for the development of new generation steel.更多还原