The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 1985
Filed:
Mar. 17, 1983
Applicant:
Inventors:
Michel Madsac, Sceaux, FR;
Thierry Hiron, Le Plessis Robinson, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D / ; C23C / ;
U.S. Cl.
CPC ...
148 166 ; 148 16 ; 148165 ; 148 203 ;
Abstract
In a surface hardening process for metal parts by nitriding or carbonitriding, the parts to be treated are placed in a furnace and maintained at a temperature of between 490.degree. C. and 750.degree. C., in a nitrogen bearing atmosphere, such atmosphere formed by introducing into the furnace a gaseous mixture comprising in particular ammonia and an oxidizing gas for accelerating the catalytic dissociation of ammonia in contact with said parts. The oxidizing gas is nitrous oxide and the gaseous mixture contains about 0.1% to 10% by volume of nitrous oxide. The invention is well suited for the surface hardening of steel parts.