热轧工艺对Fe-20Mn-3Cu-1.3C TWIP钢组织致密度和力学性能的影响

Effect of hot rolling process on microstructure density and mechanical properties of Fe-20Mn-3Cu-1.3C TWIP steel

通过真空熔炼制备出高强韧Fe-20Mn-3Cu-1.3C TWIP钢。针对该合金钢凝固组织中易形成显微缩松的问题,在总热轧压下率相同的条件下,研究了道次平均压下率的变化对消除合金钢微孔缺陷和力学性能的影响。结果表明,随着道次平均压下率由35.96%提高至48.75%,合金内部微孔面密度显著降低,平均晶粒尺寸减小,合金的屈服强度、抗拉强度、强塑积大幅度提高。当道次平均压下率为48.75%时,屈服强度、抗拉强度和伸长率分别为536.70 MPa、1161.49 MPa、95.60%,强塑积高达111038.44 MPa.%,与当道次平均压下率为35.96%时相比,强塑积提高了47.70%,这一结果是目前TWIP钢综合力学性能数据的最高值。表明提高道次平均压下率消除缩松缺陷是提高该TWIP钢力学性能的关键。

Fe-20Mn-3Cu-1.3C TWIP steels with the combination of high strength and high toughness were prepared by vacuum melting. To address the problem that micro-porosity easily formed in the solidification structure, the effect of average reduction per pass on micropore elimination and tensile mechanical properties under the same total hot rolling reduction was studied. The results show that when the average reduction per pass raises from 35.96% to 48.75% , the section density of mieropore in the alloys remarkably decreases and the average grain size decreases as well, and the yield strength, tensile strength and strength-plasticity product are also greatly enhanced. When the average reduction per pass is 48.75% , the yield strength, tensile strength and elongation percentage is 536.70 MPa, 1161.49 MPa and 95.60% , respectively. And the strength-plasticity product is 111038.4 MPa·%, which increases by 47.70% compared with the data obtained from the average reduction per pass at 35.96% and the result is the highest value of performance data of TWIP steels so far. Eliminating micropore by increasing the average reduction per pass is the key to improve mechanical properties of the TWIP alloy.