The Effect of Insert of WC Powder on the Surface Hardening of Non Magnetic Foundry Materials

Abstract

Non magnetic foundry materials such as the austenitic stainless cast steel had not been used for abrasionresistant materials, because their hardnesses were very low. Usually, ceramics, cermets and cemented carbidesare used for the abrasion resistant materials even though they are expensive compared with foundrymaterials.In this study, WC powder were inserted by using the austenitic stainless cast steel (JIS SCS13A) and theaustenitic cast iron (JIS FCA-NiCr202) for producing surface hardened non magnetic materials. The meltingtemperature (pouring temperature) is lower in the austenitic cast iron than in the austenitic stainless cast steelwhile the fluidity of the melts is superior in the austenitic cast iron. For the WC powder inserted specimens, the hardness, the abrasion resistance and the magnetic property were examined.As a result, it was found that the hardness in the region of inserted WC powder was much higher than thatof base metals of the cast steel and the cast iron, and that the magnetic permeability did not change by theinserting. Especially, a lot of WC powder was found to dissolve into the base metal in the cast steel than inthe cast iron. In the case of the cast steel, Fe3W3C compound phase having high hardness of HV800 wasformed in the region of inserted WC powder. The hardness in the region of inserted WC powder was higherin the cast steel than in the cast iron, because the cast steel contained a lot of chromium compared with thecast iron.