采用中频炉+电渣重熔方法制备了一种新型硫-铅复合铁素体易切削不锈钢,利用光学显微镜、扫描电镜、能谱仪和超精密数控车床对该钢的化学成分、显微组织、夹杂物及切削性能进行了研究.结果表明:试验钢棒材及其成品线材、进口SF20T钢成品线材中易切削相均为MnS、铅及其与碲形成的复合夹杂物,棒材中MnS呈纺锤形,经冷拔后的成品线材中MnS横向呈细小的椭圆形并沿拉拔方向呈断续、串链状分布,比SF20T钢成品线材的横、纵向尺寸均小;试验钢成品线材基体组织为铁素体,晶粒度约为10级,在高速中等进给量下切削性能良好,可兼顾切屑形貌和表面粗糙度的要求.

A new type S-Pb ferritic free-cutting stainless steel was manufactured by intermediate frequency furnace and electroslag remelting.The chemical composition,microstructure,inclusion and cutting performance were analyzed by optical microscopy,SEM,EDS and ultra-precision CNC lathe.The results show that the free-cutting phases of the tested steel bar,product wire and imported SF20T product wire contained MnS,Pb and the composite inclusion consisted of MnS,Pb and Te.MnS in the steel bar was spindle.MnS in the cold-drawn product wire was fine and elliptical in transverse direction,and distributed along the drawing direction in forms of chain and intermittence,with the size smaller than the transverse and lognitudinal size in SF20T product wire.The matrix microstructure of the tested steel product wire was ferrite with the grain size scale of 10.The cutting performance of the steels was good at high-speed and medium feeding rate,this could meet the requirements to the chip morphology and surface roughness.