Stainless steel for anti-friction bearing and method of making
AssigneeMinebea Co., Ltd.
InventorsRikuro Obara, Yutaka Daikuhara
Life of this patent
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Abstract
To provide a stainless steel for anti-friction bearings, which is obtained by making its eutectic carbide contents finer in particle diameter and suppressing the generation of non-metallic substances to an extremely low level, thus having a homogenious and dense structure and permitting highly accurate machining. The provided stainless steel is composed of 0.60 to 0.75% of carbon, 10.5 to 13.5% of chromium, 1.0% or below of silicon and 0.3 to 0.8% of manganese, % being by weight, the remainder of the composition being iron and inevitably introduced impurities, has a hardness of HRC 58 or above, contains eutectic carbide particles of 10 .mu.m and below in diameter, and has oxygen and titanium concentrations each of 10 ppm or below.
Claims10
A stainless steel for an anti-friction bearing composed of 0.60 to 0.75% of carbon, 10.5 to 13.5% of chromium, 1.0% or below of silicon, and 0.3 to 0.8% of manganese, % being by weight, the remainder of the composition being iron and inevitably introduced impurities, having a hardness of HRC 58 or above, containing eutectic carbide particles of 10 .mu.m and below in diameter, and having oxygen and titanium concentrations each of 10 ppm or below.
A stainless steel for an anti-friction bearing composed of 0.60 to 0.75% of carbon, 10.5 to 13.5% of chromium, 1.0% or below of silicon, and 0.3 to 0.8% of manganese, % being by weight, the remainder of the composition being iron and inevitably introduced impurities, having a hardness of HRC 58 or above, containing eutectic carbide particles of 10 .mu.m and below in diameter, having a titanium concentration of 10 ppm or below, and having an oxygen concentration of 10 ppm or below by extending a time of purging gases from a molten steel in a process of manufacturing.
In a process of manufacturing for an anti-friction bearing a stainless steel having a hardness of HRC 58 or above and composed of 0.60 to 0.75% of carbon, 10.5 to 13.5% of chromium, 1.0% or below of silicon, 0.3 to 0.8% of manganese, % being by weight, and including steps of providing a titanium concentration of 10 ppm or below and providing eutectic carbide particles of 10 .mu.m or below in diameter, the improvement comprising:
- extending a time of purging gases from molten steel in the process to provide an oxygen concentration of 10 ppm or below.
In a process of manufacturing a stainless steel having a hardness of HRC 58 or above and composed of 0.60 to 0.75% of carbon, 10.5 to 13.5% of chromium, 1.0% or below of silicon, 0.3 to 0.8% of manganese, % being by weight, and including steps of providing a titanium concentration of 10 ppm or below and providing eutectic carbide particles of 10 .mu.m or below in diameter, the improvement comprising:
- extending a time of purging gases from molten steel in the process to provide an oxygen concentration of 10 ppm or below.
Dependencies are inferred from the claim text.