PURPOSE: To enhance the cutting performance of the titled member by forming the interior of a superhard WC alloy member with carbonitride, etc. of a specified metal, an Fe group metal and WC, the 1st surface layer with the carbonitride, etc. and the Fe group metal, and the 2nd layer with the Fe group metal and WC at suitable hardness.
CONSTITUTION: The interior of a superhard WC alloy member is formed with a composition consisting of 5W30wt% of ≥1 kinds of compound with NaCl type crystal structure selected from carbides, nitrides and carbonitrides of the IVa, Va and VIa group metals in the periodic table, 5W30wt% of ≥1 kinds of Fe group metal and the balance WC with inevitable impurities. A part having 5W40μm depth from the surface is formed with the 1st layer having a composition consisting of 2W 15wt% of ≥1 kinds of Fe group metal and the balance said NaCl type compound with impurities and having higher N or N+O content than the interior. A part having 2W50μm thickness just below the 1st layer is formed with the 2nd layer having a composition consisting of 5W30wt% of ≥1 kinds of Fe group metal and the balance WC with impurities and having lower hardness than the interior by 5W50% Hv.
HAYASHI KOUJI
SUGISAWA TAIJIROU
