45钢和球墨铸铁等离子弧淬火区特点的研究

为深入研究45钢和球墨铸铁等离子弧表面淬火区的特点，采用显微分析技术和硬度实验分析方法，研究了这两种材料等离子弧淬火区的组织差异及硬度分布情况.结果表明：在一定的等离子弧淬火工艺规范下，45钢与球墨铸铁由于化学成分不同，在淬火区沿深度方向各部位的组织均存在明显差异：通常在淬火区的表层接近于激光淬火状态，两种材料得到的隐晶马氏体形态不同；在淬火区内部接近于低能流密度淬火的情况，得到的混合组织形态也各异.两种材料硬化层的硬度提高幅度不同，但都无明显硬度下降梯度.

Study on characteristics of plasma-arc quenched zonefor 45 steel and ductile cast iron

To clarify the characteristics of the plasma-arc quenched zone for 45 steel and ductile cast iron,the microstructural difference and hardness distribution were investigated based on micro-analysis technology and hardness test.The results show that under certain plasma-arc quenching technical criterions,the obvious microstructural difference will appear in the quenched zone along depth direction due to the difference in the chemical composition of 45 steel and ductile cast iron.Generally,the surface layer of the quenched zone is similar to that of laser quenching,and the morphology of cryptocrystalline martensite acquired for two materials is different.Inside the quenched zone corresponding to lower energy current density quenching,the microstructural morphology is different too.The increase in the hardness of two materials is different,but there is no obvious decreasing gradient of hardness.