Steel composition
AssigneeBorgWarner Inc.
InventorsYumin Wang, Yoshito Hanayama, Doug Fornell, Naosumi Tada, Kunihiko Mishima
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Abstract
Chain parts and other steel articles are provided with hard, wear-resistant carbide coatings by tumbling them in a heated retort with a particulate mix which includes a source of vanadium and/or niobium. The steel substrate comprises a steel having at least 0.2% carbon, preferably 0.7-1.2%. Where the chromium content of the steel is 4-12%, preferably 4-8%, the chemical deposition process includes drawing a small amount of chromium from the steel substrate into the vanadium or niobium carbide coating, where it is distributed substantially homogeneously, helping to provide adhesion strength to the coating.
Claims4
A layered steel composition comprising, in weight percent, (a) a core composition comprising:
- C Cr Mn Si Mo P S Al 0.7-1.2 4-8 0.25- 0.25- 0.2- 0.03 max 0.03 max 0.05 max 0.45 0.55 0.55
- and (b) a coating composition thereon comprising 97-99% by weight carbide of at least one Group 5 metal having an atomic number no greater than 41.
Dependencies are inferred from the claim text.