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. 12, 1983
Filed:
Nov. 21, 1980
Richard S Polizzotti, Milford, NJ (US);
Richard C Krutenat, New Providence, NJ (US);
Exxon Research and Engineering Co., Florham Park, NJ (US);
Abstract
Protection of cast austenitic stainless steel tubes is provided against initiation of carburization by (a) cold-working the inner surfaces of said tubes to deform the surface to such a degree that upon the subsequent heat treatment of step (b) below, dissolution of the M.sub.23 C.sub.6 carbides in the deformed region is accompanied by recrystallization resulting in a refined micrograin structure in the deformed regions to a substantially uniform minimum depth of about 20 microns; and (b) heating the cold-worked inner surfaces of said tubes, for an effective amount of time, at a temperature between its recrystallization temperature and its melting temperature, in an atmosphere of which the oxygen partial pressure is at least oxidizing with respect to chromium.