20Mn2钢中添加ZrC粒子获得超细晶粒的研究

在 2 0Mn2钢熔炼过程中加入一定体积分数和一定粒径的ZrC粒子以起形变核心和再结晶核心作用 ,利用大轧制变形加速奥氏体和铁素体晶粒发生再结晶而细化晶粒 ,分析了ZrC粒子对晶粒细化的作用以及合金元素和轧制变形对力学性能的影响。试验结果表明 ,试验钢晶粒尺寸被细化到 1～ 2 μm。与 2 0Mn2钢相比 ,S1钢淬火态抗拉强度和屈服强度分别提高 131.8%和 187.0 % ,2 0 0℃ 2 0 0min低温回火态分别提高 110 .6 %和 16 3.8% ,同时 ,延伸率也有所提高 ;S2钢油淬态的抗拉强度和屈服强度分别提高为 34.2 %和 39.9% ,钢S2油淬低温回火态分别提高了 2 9.9%和 35 .0 % ,与 2 0Mn2钢的塑性指标相比 ,油淬及低温回火态延伸率分别提高了 90 %和 111%。

Study on super-fine grains obtained in 20Mn2 steel by adding ZrC

A certain volume fraction and size distribution of ZrC particles were introduced into 20Mn2 steel when melting. The ZrC particles acted as deformation and recrystallization cores when rolling deformation, therefore, austenite and ferrite grains were refined greatly due to the acceleration of recrystallization. The effect of ZrC particles on grain refining and the effect of alloy elements and rolling deformation on mechanical properties were investigated. The results showed that the grain size of steels were refined to 1～2μm. Compared with that of standard 20Mn2 steel, the ultimate strength and yield strength of water-quenched S1 steel were increased by 131.8% and 187.0% respectively,and after being low-temperature tempered at 200℃ for 200minutes, the increment of ultimate strength and yield strength were 110.6% and 163.8% respectively, and the elongation was increased as well;the ultimate strength and yield strength of oil-quenched S2 steel were increased by 34.2% and 39.9%, and 29.9% and 35.0% for low-temperature tempered specimens, the plasticity of oil-quenched and low-temperature tempered specimens were increased respectively by 90% and 111% as compared with 20Mn2 steel.