Ti，N，Mg对M2高速钢凝固组织和硬度的影响

EFFECT OF Ti,N,Mg ON THE MICROSTRUCTURES AND HARDNESS OF M2 HIGH SPEED TOOL STEEL

为了改善Ｍ２高速钢共晶碳化物的分布，本文利用小凝固试样变质的方法研究了Ｔｉ，Ｎ和Ｍｇ对Ｍ２高速钢凝固组织和硬度的影响。试验结果表明，加入Ｔｉ或Ｔｉ－Ｎ后，共晶碳化物形态和分布有很大改善，而加入Ｔｉ－Ｎ后对凝固组织有轻微的细化作用，但只添加Ｔｉ不补碳时，钢的淬火硬度和回火硬度均下降；加入适量的Ｍｇ可以使片状的Ｍ＿２Ｃ型共晶碳化物转变为鱼骨状的Ｍ＿６Ｃ型共晶碳化物，使其分布有所改善；Ｔｉ和Ｍｇ复合加入可以明显地改善共晶碳化物的分布。

This paper deals with the microstructure and hardness of small solidi- fied samples inoculated with Ti, N and Mg during solidification in order to modify the distribution of the eutectic carbides of M2 high speed tool steel. The experiments show that the shape and distribution of the eutectic carbides are modified with adding Ti or Ti-N,and somewhat the microstructures are fined when the steel is inoculated with Ti-N,but only adding Ti the hardening hardness and the temper hardness of the steel can be reduced. The experiments also show that the larnellar eutectic car- bide M_2C can be changed into the fishbone eutectic carbide M_6C and the distribution of eutectic carbides can be modified a little if adding appropriate Mg,but the distribu- tion of eutectic carbides of M2 high speed tool steel ctn be modified considerably when adding proper Ti and Mg.