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.

Date of Patent:
Oct. 06, 1992

Filed:

Oct. 10, 1990
Applicant:
Inventor:

Hideyuki Ohma, Aichi, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D / ; C22C / ;
U.S. Cl.
CPC ...
148609 ; 148325 ; 420 70 ;
Abstract

A high toughness ferritic stainless steel having the excellent cold workability and the excellent heading workability suitable for the plastic working of screws, which consists essentially of, by weight percentage, C.ltoreq.0.03%, P.ltoreq.0.040%, S.ltoreq.0.010%, Si.ltoreq.1.0%, Mn.ltoreq.1.0%, 11.5%.ltoreq.Cr.ltoreq.22.0%, 0.05%.ltoreq.Nb.ltoreq.0.80%, N.ltoreq.0.025%, if necessary at least one selected from 0.2%.ltoreq.Cu.ltoreq.1.0%, 0.01.ltoreq.Mo.ltoreq.2.00%, 0.020%.ltoreq.Ni.ltoreq.1.50% and the balance being Fe and inevitable impurities, and the number of inclusions larger than 20 .mu.m amoung inclusions composed of carbo-nitrides of Nb, Ti and/or Zr in the steel is not more than 20. In the production of the high toughness ferritic stainless steel, the rolling material having the above-mentioned chemical compositions is heated to 1200.degree. C. or above at the rod rolling.


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