钒、钛、稀土元素在正火钢中的存在

THE EXISTENCE FORM OF VANADIUM,TITANIUM AND RARE EARTH IN NORMALIZED STEEL

以添加V、V—Ti、V—RE等元素的中、低碳非调质钢为例,应用物理化学相分析及电子显微分析技术,研究了正火状态下合金元素的存在状态。表明950C正火后,钒、钛减少了碳化物总量,增加了铁素体的相对量。锰主要存在于铁素体中,仅少量溶入渗碳体和碳化钒中。钛主要以TiC、TiN形式存在。钒以VC形式存在,少量溶入渗碳体。V、Ti总有少部分滞留于铁素体中。稀土元素可固溶入钢中,增加过冷奥氏体的稳定性,影响分解产物的形态和性能。

The existence form of alloying elements has been investigated by means of TEM and extractive analysis methods in the normalizes low and mediun carbon HSLA steels.The steels have been alloyed with vanadium,vanadium—titanium or vanadium—rare earth.The result shows that the total amount of carbides is diminished and the relative amount of ferrite is increased after normalizing at 950℃.A large amount of manganese is dissolved in ferrite,a little exists in cementite and V_4C_3.The titanium mostly exists in TiC and TiN.A large amount of vanadium exists as V_4C_3 and a little vanadium dissolves into cementite.A litile vanadium and titanium always exist in ferrite.The rare earth elements may dissolve into the steel.The amount of solution accounts for 0.027%,it moves CCT curves to the right,and increases stability of undercooling austenite.Besides,affects the form and properties of decomposition products.