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:
Apr. 25, 1978
Filed:
Feb. 02, 1977
Nippon Steel Corporation, Tokyo, JA;
Abstract
The present invention relates to a heat treatment process of high-carbon chromium-nickel heat-resistant stainless steels for the purpose of improving the creep rupture strength of the steel at temperatures over about 800.degree. C particularly at about 1000.degree. C. The feature of the present invention lies in that heat-resistant stainless steels containing 0.2 - 1.5% C, 15 - 40% Cr, 10 - 50% Ni, 5% or less Si, 15% or less Mn, with the balance Fe, and impurities are heated for 1 to 60 minutes in a temperature range from 1280.degree. C to 1350.degree. C and then quenched to room temperature at cooling rates higher than 200.degree. C/min. in order to produce the eutectic carbide structure consisted of the matrix metal and carbide phases in which M.sub.7 C.sub.3 -type carbide is contained not less than 25% by weight of the total weight of the carbides, that are present in the said eutectic carbide structure, at grain boundary triple points, along grain boundaries and within grains.