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Method of producing stainless steel product
| Details |
Inventors: Murakami, Shinichi; Akamatsu, Katsutaro; Yoshimitsu, Arata; Noji, Sueyoshi;
Assignee: Kubota, Ltd. (Osaka, JP)
Primary Examiner: Stallard; W.
Assistant Examiner:
Attorney, Agent or Firm: Wenderoth, Lind & Ponack
A method of producing stainless steel products superior in intergranular corrosion resistance and applicable to ultrasonic flaw detection, in which austenite group stainless cast steel containing 5 to 40% of ferrite phase is employed as base material, part or all of which base material is subjected to plastic deformation or plastic processing such as pulling, pressing, bending, tension processing and the like, with subsequent recrystallizing heat treatment for the improvement of intergranular corrosion resistance by making its cast structure fine and reducing surface roughening developed due to deformation during the plastic processing, and for making it possible to successfully apply ultrasonic flaw detection to such cast steel products. |
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DETAILED DESCRIPTION What is claimed is: 1.
A method of manufacturing a stainless steel product which comprises applying plastic cold processing, at a processing degree selectively equal to or larger than 10%, to at least a predetermined portion of a base material of a centrifugal cast steel product of austenite stainless steel containing, at centrifugal casting, 5 to 40% of a ferrite phase, said cast steel product having a configuration close to that of the final product and a coarse cast structure, subsequently applying a recrystallizing treatment to said cast and cold worked steel product for making the cast structure thereof fine, which recrystallizing treatment comprises heating said cast and cold worked steel product up to the solution heat treatment temperature of 1000 to 1250.
degree.
C.
and maintaining the thus heated product at approximately the same temperature to cause recrystallization thereof, and quenching the thus treated cast steel product after recrystallization.
2.
A method of manufacturing a stainless steel product as claimed in claim 1, wherein said plastic cold processing is effected by mechanical deformation of said base material.
Description:
The present invention relates to a stainless steel product and more particularly, to a method of manufacturing a stainless steel product having superior intergranular corrosion resistance and capability of being subjected to ultrasonic flaw detection.
As is well known in the art, for important parts, for example, of atomic power plant equipment, various apparatuses related to petrochemical industries or the like, non-destructive tests such as radiographic inspection and ultrasonic flaw detection are required in many cases for strict quality control of these parts.
Although stainless cast steel products of austenite group are largely employed for such parts, for example, pipes, elbows, etc.
, in petroleum purification owing the their superior corrosion resistance, these stainless cast steel products are generally coarse in cast structure and consequently unsuited to ultrasonic flaw detection, thus requiring the radiographic inspection to be employed for flaw detection
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Nonmetallic Processes 
