METHOD OF PRODUCTION OF ROLLING BEARING

WIPO Patent Application WO/1999/010557

A1

A method of producing a rolling bearing, wherein, when at least one of an inner race, an outer race and a rolling element is produced by conducting carburization, hardening and tempering of an alloy steel containing 0.05 to 0.5 wt.% of carbon, 0.5 to 18 wt.% of chromium, not greater than 1.5 wt.% of silicon, not greater than 5 wt.% of molybdenum, not greater than 4.0 wt.% of vanadium, not greater than 4 wt.% of nickel and not greater than 8 wt.% of tungsten, the carburization is effected by vacuum carburization. This vacuum carburization is conducted by introducing an acetylene type carburizing gas into a heating atmosphere held at a reduced pressure, and after carburization/diffusion is effected, hardening and tempering are further carried out. Therefore, carburization at a Cr content of at least 3.0 wt.%, that has been difficult in conventional gas carburization (preliminary oxidation + gas carburization) can be extended up to Cr content of 18 wt.% by effecting vacuum carburization.

KIUCHI AKIHIRO (JP)
OKITA SHIGERU (JP)
YAMAMURA KENJI (JP)

PCT/JP1998/003782

March 04, 1999

August 26, 1998

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NSK LTD (JP)
KIUCHI AKIHIRO (JP)
OKITA SHIGERU (JP)
YAMAMURA KENJI (JP)

C22C38/22; C22C38/24; C23C8/22; C23C8/80; F16C33/30; F16C33/62; (IPC1-7): C23C8/22; C22C38/00; F16C33/32; F16C33/34; F16C33/64

JPS5629667A	1981-03-25
JPS61236923A	1986-10-22
JPH0426752A	1992-01-29
JPH08325701A	1996-12-10

Watanabe, Toshihiko (8th floor 17-1, Toranomon 1-chome Minato-ku Tokyo, JP)

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