HIGH BEARING-STRENGTH STEEL PARTS AND PROCESSES FOR THE PRODUCTION THEREOF

Title:

HIGH BEARING-STRENGTH STEEL PARTS AND PROCESSES FOR THE PRODUCTION THEREOF

Document Type and Number:

WIPO Patent Application WO/1998/027242

Kind Code:

A1

Abstract:

High bearing-strength steel parts useful for strengthening and downsizing parts which are to undergo rolling and sliding and therefore required to have high rolling strength and wear resistance, for example, gear, cam or bearing parts; and processes for the production thereof. The surface hardness of the steel part can be enhanced by dispersing nitride and/or carbonitride fines having a mean particle diameter of 0.3 m$g(m) or below in the surface layer to come into contact with a counter member to thereby form a composite structure containing very fine irregular martensite leaves divided by the nitride and/or carbonitride fines and by dispersing carbide particles having a size of 3 m$g(m) or below in the surface layer. The steel part can be produced by making nitrogen penetrate the surface layer by nitriding or carbo-nitriding to thereby form very fine grains of A1N, and subjecting the resulting products to quenching from a temperature region wherein the matrix phase is austenite, and, if necessary, tempering.

Inventors:

TAKAYAMA TAKEMORI (JP)
HAMASAKA NAOJI (JP)

Application Number:

PCT/JP1997/004430

Publication Date:

June 25, 1998

Filing Date:

December 03, 1997

Export Citation:

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Assignee:

KOMATSU MFG CO LTD (JP)
TAKAYAMA TAKEMORI (JP)
HAMASAKA NAOJI (JP)

International Classes:

C21D7/06; C22C38/00; C23C8/28; C23C8/32; C23C8/22; C23C8/34; C23C8/80; F16C33/30; (IPC1-7): C22C38/00; C22C38/24; C23C8/32; C23C8/34

Foreign References:

JPH083720A	1996-01-09
JPH0488148A	1992-03-23
JPH0617224A	1994-01-25
JPH05320822A	1993-12-07
JPH073393A	1995-01-06
JPH0881734A	1996-03-26
JPH0570925A	1993-03-23
JPH02277764A	1990-11-14

Other References: