Q960D高强钢板回火工艺研究

STUDY ON TEMPERING PROCESS OF Q960D HIGH STRENGTH STEEL PLATE

为拓宽高强钢板的回火工艺窗口,采用轧后空冷弛豫技术结合在线淬火(DQ)的工艺生产出了综合性能优良的低合金高强钢板Q960D,并进一步研究了不同回火温度对钢板性能和组织的影响。结果表明,经560~650℃回火处理后,钢板显微组织均为板条马氏体,随着回火温度升高,板条宽度逐渐增大,板条内部和界面的析出物逐渐增多。屈服强度较直接淬火后强度有所升高,但整体较稳定;维氏硬度范围为350~410 HV,且随回火温度升高,硬度逐渐下降。试验钢板回火后强度稳定、塑韧性佳,说明采用轧后空冷弛豫技术结合在线淬火(DQ)工艺生产的Q960D高强钢板热稳定性好,可拓宽其回火工艺窗口。

In order to widen the tempering process window of high strength steel plate,the low alloy high strength steel plate Q960D with excellent comprehensive properties was produced by using post-rolling air cooling relaxation technology combined with on-line quenching(DQ)process,the effect of different tempering temperature on the properties and microstructure of steel plate was further studied.The results show that the microstructure of the steel plate after tempering at 560~650℃is Lath martensite.With the tempering temperature increasing,the lath width and the precipitates in the Lath and at the interface increase gradually.The yield strength is higher than that after direct quenching,but the overall strength is more stable,and the Vickers hardness ranges from 350 HV to 410 HV,and the hardness decreases gradually with the increase of tempering temperature.The results show that the Q960D high strength steel plate produced by post-rolling air cooling relaxation technology combined with on-line quenching(DQ)process has good thermal stability and can widen its tempering process window.