To provide a method for manufacturing a high bearing pressure resistant member, which carburizes a low C material into high concentration, further prevents the growth of carbide by controlling its generation, and prevents degradation of the surface fatigue strength, and to provide a high bearing pressure resistance member, having finely and uniformly precipitated carbide on the surface layer and excellent in the rolling fatigue life.
This method comprises vacuum carburizing a steel for a machine structure (the first carburization), which includes, for instance, 0.15-0.40% C, 1.2-3.2% Cr, and 0.25-2.0% Mo, vacuum diffusing the surface C at a solid solution temperature of carbide, for instance, at 900-1050°C, to make the surface C quantity after the treatment to be 0.5-0.7%, and lowering the temperature from the above vacuum diffusion temperature to a quenching temperature of 870-920°C, for instance, at a cooling rate of 1-10°C/min, for instance, to increase the C concentration on the material surface to 0.7-1.0%, for instance, by diffusing carbon during holding it at the above quenching temperature.
KIMURA TOSHIMITSU
YAMAGUCHI TAKUO
OTANI KEIZO
UCHIYAMA NORIKO
NISSAN MOTOR