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

摘要

Non magnetic foundry materials such as the austenitic stainless cast steel had not been used for abrasion resistant materials, because their hardnesses were very low. Usually, ceramics, cermets and cemented carbides are used for the abrasion resistant materials even though they are expensive compared with foundry materials. In this study, WC powder were inserted by using the austenitic stainless cast steel (JIS SCS13A) and the austenitic cast iron (JIS FCA-NiCr202) for producing surface hardened non magnetic materials. The melting temperature (pouring temperature) is lower in the austenitic cast iron than in the austenitic stainless cast steel while 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 that of base metals of the cast steel and the cast iron, and that the magnetic permeability did not change by the inserting. Especially, a lot of WC powder was found to dissolve into the base metal in the cast steel than in the cast iron. In the case of the cast steel, Fe3W3C compound phase having high hardness of HV800 was formed in the region of inserted WC powder. The hardness in the region of inserted WC powder was higher in the cast steel than in the cast iron, because the cast steel contained a lot of chromium compared with the cast iron.