NAK80模具钢中夹杂物的研究

Research on inclusions of die steel NAK80

NAK80是一种预硬塑胶模具钢,对应国产牌号1Ni3MnCuMoAl,因其是预硬状态交货,不再需热处理,加之良好的抛光性和雕饰性,在塑胶方向得到广泛应用。而钢的纯净度直接决定了该钢的抛光性,研究发现NAK80模具钢中夹杂物主要以AlN为主,若钢中含有微量的Ti,TiN会优先析出,AlN数量会大大减少。因该钢的AlN在固液两相区析出,电渣重熔对去除AlN夹杂物效果微乎其微,随着熔速的增快,AlN尺寸反而有长大的趋势,而在真空自耗重熔情况下,AlN会发生分解,AlN夹杂物也随之减少。本文主要研究分析NAK80钢中AlN夹杂物的形态、尺寸及形成方式,以及在经过电渣及真空自耗二次重熔后夹杂物的变化,和一些过程参数对AlN夹杂物的影响。

NAK80 is a kind of prehardened plastic die steel, corresponding to the domestic brand 1Ni3MnCuMoAl.Because it is delivered in the prehardened state, it does not need reheating treatment, and has good polishing and carving properties,so it is widely used in the plastic field. The purity of the steel directly determines the polishing property of the steel. It is found that the inclusions in NAK80 die steel are mainly AlN. If the steel contains a small amount of Ti, TiN will be preferentially precipitated and the amount of AlN will be greatly reduced. Since AlN of the steel is precipitated in the solid-liquid two-phase region, the effect of electroslag remelting on removing AlN inclusions is very small. With the increase of melting speed, the size of AlN tends to grow. In the case of vacuum consumable remelting, N will be greatly reduced and AlN inclusions will also decrease. It is found that the inclusions in NAK80 are mainly AlN. This paper mainly studies and analyzes the morphology, size and formation mode of AlN inclusions in NAK80 steel, the changes of inclusions after electroslag and vacuum consumable secondary remelting, and the effects of some process parameters on AlN inclusions.