PURPOSE: To obtain a sintered alloy for surface hardening having high surface hardness and practically free from cracking by blending specific amounts of powdered Ti, V, and Cr and powdered Zr, Nb, etc., with a powder of Co or Co-Ni alloy containing specific amounts of B and then sintering the resulting powder mixture.
CONSTITUTION: One or more kinds among powdered Ti, V, and Cr and one or more kinds among powdered Zr, Nb, Mo, Hf, Ta, and W are blended by ≤4 times B and ≤2 times B, respectively, with powdered Co or Co-Ni alloy or powdered Ni alloy containing 4-6wt.% B. The above powders are mixed to the full and the resulting uniform powder mixture is compacted. The resulting green compact is heated up to an eutectic temp. of about 1060-1140°C. By the above heating treatment, B in Co and Ni is subjected to reaction sintering together with V, W, etc., having higher affinity, by which borides having high melting point and high hardness are formed. By this method, the sintered alloy for surface hardening having high surface hardness and high toughness, highly resistant to cracking, and suitable for wear resistant material for high temp. use can be obtained.
HAYASHI YOICHIRO
OCHI DAISUKE
SUMITOMO JUKIKAI CHUTAN KK
| JPS5867804A | 1983-04-22 | |||
| JPS5462118A | 1979-05-18 |