Surface Hardening of Some Cast Irons with Inserted Hard Alloy Particles

抄録

In this paper, two experiments for locally hard facing of cast iron and cast steel will be presented. In thecase of locally hard faced spheroidal graphite cast iron with hard alloy briquettes, the inserted layer asformed with penetration of the molten cast iron among tungsten carbide (henceforth, it is described as WC) particles in the hard alloy briquette. The base metal of inserted layer showed a microstructure of gray castiron due to a hindrance to spheroidalization caused by a reaction the molten cast iron to the elements of Wand Co in the hard alloy. The hardness of mother spheroidal graphite cast iron was about Vickers hardness (henceforth, it is described as HV) 200 while the hardness of the inserted layer ranged from HV600 toHV1600.
In the case of locally hard faced cast steel, the inserted layer was also formed with similar process to thatof the spheroidal graphite cast iron, while intermediate phases with very hard complex carbide were formedat the bonding region between the inserted layer and the base metal. The hardness of mother cast steel wasabout HV300, while the hardness of the inserted layer ranged from HV800 to HV1400. Especially, the intermediatelayer with complex carbide showed the highest hardness of HV1800. Therefore, the inserted methodswith hard alloy particles are considered to be a very effective one for locally hard facing of cast iron andcast steel.