轧后冷却工艺对低碳高强复相钢组织和性能的影响

Effect of cooling process after rolling on microstructure and properties of a low-carbon high-strength complex-phase steel

设计了3种不同轧后冷却速率和快速冷却终点温度,进行轧后冷却实验,结合扫描电子显微镜、透射电子显微镜和拉伸实验等,研究了冷却工艺对低碳高强复相钢组织和性能的影响。结果表明,在同一冷却速率下,随着快速冷却终点温度的增加,形成的贝氏体逐渐减少,马奥岛(M/A)明显粗化,且M/A岛比例增加,组织整体形貌从板条状变成块状。此外,在相同冷却速率下,随着快速冷却终点温度的增加,钢的强度逐渐降低,伸长率增加。另外,当快速冷却终点温度为480℃时,随着冷却速率的减低,贝氏体逐渐消失,且M/A岛逐渐粗化,同时随着冷却速率的降低,钢的强度降低,伸长率有所增加。本研究结果可以为生产和优化低碳高强复相钢的轧后冷却工艺制度提供参考。

Three cooling rates and rapid cooling terminal temperatures were designed to study the effect of cooling process on microstructure and properties of a low-carbon high-strength complex-phase steel by scanning electron microscope,transmission electron microscope and tensile tests.The results show that with the increase of rapid cooling terminal temperature at the same cooling rate,the BF amount gradually decreases,the M/A island coarsens,the ratio of M/A islands increases and the microstructure morphology changes from lath to block.In addition,at the same cooling rate,with the increase of rapid cooling terminal temperature,the tensile strength of steel gradually decreases and the elongation increases.Moreover,when rapid cooling terminal temperature is at 480℃,BF gradually disappears and M/A islands gradually coarsen with the decrease of cooling rate.With the decrease of cooling rate,tensile strength decreases and elongation increases.The results provide theoretical guidance for optimization of cooling process of low-carbon high-strength complex-phase steel.