良好超塑性变形行为高碳低合金钢的研制

Development of high-carbon low-alloy steel with good superplastic deformation behavior

制备了添加氧化物的高碳低合金钢oxide-HCS和同时添加氧化物和Al的oxide-HCS-Al,研究了两种钢的超塑性变形行为。结果表明:Al和氧化物的加入有利于抑制网状渗碳体的形成,添加氧化物的高碳钢的珠光体组织更加细小均匀。oxide-HCS-Al钢经850℃淬火+620℃×2 h回火处理后,能够得到尺寸细小的碳化物(0.25μm),在750℃、ε^(*)=5×10^(-4) s^(-1)条件下拉伸,其伸长率高达604.4%,该数值相比之前研究的1.5C-1.5Cr-2.2Al未添加氧化物高碳钢提高了140%。620℃回火的oxide-HCS-Al钢的变形激活能为207.9 kJ·mol^(-1),m值大于0.3,且750℃时变形的m值最大(0.46),在720~775℃温度区间内试样展现出良好的抗颈缩能力,表明钢中添加Al和氧化物纳米颗粒能显著提升材料的高温变形性能。

High-carbon low-alloy steel oxide-HCS with oxides added and oxide-HCS-Al with both oxides and Al were prepared,and the superplastic deformation behavior of the two steels was studied.The results show that the addition of Al and oxide is beneficial to inhibiting the formation of net-work cementite,and the pearlite structure of high carbon steel with oxides added is more fine and uniform.After quenched at 850℃and tempered at 620℃×2 h,oxide-HCS-Al steel can obtain fine carbides(0.25μm),and the elongation reaches 604.4%when it is stretched at 750℃andε^(*)=5×10^(-4) s^(-1),which is 140%higher than that of the 1.5C-1.5Cr-2.2Al high-carbon steel without oxide added in previous study.The activation energy of oxide-HCS-Al steel tempered at 620℃is 207.9 kJ·mol^(-1),the m value is greater than 0.3 and is the largest(0.46)when it is deformed at 750℃,and the sample deformed at 725-775℃shows good resistance to necking,which indicates that the addition of Al and oxide nano particles to the steel can significantly improve the high temperature deformation properties of the material.