回火温度对Ti-V-Mo微合金化马氏体钢析出相和力学性能的影响

Effect of tempering temperature on precipitation and mechanical properties of Ti-V-Mo microalloyed martensitic steel

利用微观分析和物理化学相分析法,对不同回火温度(550,600,650℃)保温1 h后的Ti-V-Mo微合金化马氏体钢的组织和析出相表征,并进行了强化分量的计算。结果表明,在600℃回火时具有最佳的综合力学性能:抗拉强度为1298 MPa,屈服强度为1286 MPa,伸长率为14%。强化分量计算结果表明:析出强化和细晶强化是主要的强化方式,约占总强度的40%和30%,其中析出强化分量σ_(p)为517 MPa,由5 nm以下的(Ti, V,Mo)C粒子(质量分数22%)提供。回火温度由550℃升高到600℃,抗拉强度和屈服强度均有增加,同时伸长率变化不大,其主要原因是σ_(p)对屈服强度的贡献量提高,在提高强度的同时改善了塑性。

Microstructure and precipitates of Ti-V-Mo microalloyed martensitic steel after quenching and tempering at different temperatures(550,600,650 ℃) for 1 h were characterized by microanalysis and physicochemical phase analysis, and the strengthening components were calculated. The results show that the steel has the best comprehensive mechanical properties when tempered at 600 ℃: the tensile strength is 1298 MPa, the yield strength is 1286 MPa and the elongation is 14%. The calculation results of strengthening component show that precipitation strengthening and fine grain strengthening are the main strengthening mechanism, accounting for about 40% and 30% of the total strength. And precipitation strengthening component σ_(p) is 517 MPa, provided by(Ti, V, Mo) C particles(mass fraction 22%) below 5 nm. When the tempering temperature increase from 550 ℃ to 600 ℃, the tensile strength and yield strength increase, but the elongation change little. The main reason is that as σ_(p) contributes to the yield strength increasingly, the plasticity is improved with the strength increasing.