公开(公告)号：US20130004883A1

公开(公告)日：2013-01-03

申请号：US13577173

申请日：2011-02-04

申请人： Harumatu Miura ,  Kazuo Oda

发明人： Harumatu Miura ,  Kazuo Oda

IPC分类号： F16L9/02 ,  C21D9/08 ,  H01M8/04 ,  C23C8/08 ,  B21C37/06 ,  B24B1/00

CPC分类号： C23C8/26 ,  B21C37/154 ,  C21D1/06 ,  C21D1/74 ,  C21D1/773 ,  C21D6/004 ,  C21D9/08 ,  C21D9/085 ,  C21D2211/001 ,  C22C38/44 ,  C23C8/62 ,  C23C8/80 ,  F16L9/02 ,  H01M8/04201 ,  Y02P70/56

摘要： Provided is a novel high-nitrogen stainless-steel pipe which is not obtained with any conventional technique, the stainless-steel pipe having high strength, high ductility, and excellent corrosion and heat resistance and being obtained through size reduction of crystal grains and strengthening by slight plastic working besides formation of a gradient structure in which the concentration of solid-solution nitrogen continuously decreases gradually from the surface. Also provided are hollow materials of various shapes and sizes which are formed from the steel pipe and processes for producing the steel pipe and the hollow materials. An austenitic stainless-steel pipe is treated in a range of the temperatures not higher than the critical temperature for crystal grain enlargement of the steel pipe material to cause nitrogen (N) to be absorbed into the surface of the pipe and diffused into the solid phase, while minimizing the enlargement of crystal grains during the treatment. Thus, a gradient structure is formed, the structure including a part that is close to the surface part of the pipe and has been highly strengthened by the formation of a high-concentration solid solution of N and a part in which ductility gradually increases toward around the center of the cross-section of the pipe as the N concentration decreases. Thereafter, the pipe is subjected to size reduction of crystal grains by utilizing, for example, eutectoid transformation of the austenite phase, thereby greatly improving the elongation (ductility) of the steel pipe. Furthermore, the steel pipe is strengthened by slight plastic working to give a high-nitrogen austenitic stainless-steel pipe having high strength, high ductility, and excellent corrosion and heat resistance. A plurality of the thus-obtained high-nitrogen austenitic stainless steel pipes of the same quality are disposed one over another so as to result in dimensions, e.g., diameter and wall thickness, according to the use or strength level, and this pipe arrangement is united by adhesion processing through hot drawing, hot rolling, or other method to give a high-nitrogen austenitic stainless-steel pipe or hollow material which has high strength, high ductility, and heat resistance and has repetitions of the gradient structure within the wall. This stainless-steel pipe or hollow material can have large or small sizes and be of various kinds, and examples thereof include a hollow material for use as a container for storing high-pressure hydrogen gas which is for fuel cell vehicles (FCVs) and which does not suffer hydrogen gas embrittlement (HGE) in the presence of high-pressure hydrogen gas.

公开(公告)号：US11015238B2

公开(公告)日：2021-05-25

申请号：US15175537

申请日：2016-06-07

申请人： Harumatu Miura ,  ODA INDUSTRIES CO., LTD.

发明人： Harumatu Miura ,  Kazuo Oda

IPC分类号： C23C8/26 ,  C23C8/80 ,  C21D1/06 ,  C21D9/08 ,  B21C37/15 ,  C23C8/62 ,  H01M8/04082 ,  C21D1/74 ,  F16L9/02 ,  C21D1/773 ,  C21D6/00 ,  C22C38/44

摘要： A process for manufacturing a high nitrogen stainless steel pipe material includes keeping an outside surface and/or an inside surface of an austenite stainless steel pipe material in contact with a substance that becomes a nitrogen (N) source, heating the steel pipe together with the nitrogen source substance at a temperature of 800° C. to 1100° C. in a range of temperatures not higher than the critical temperature for crystal grain enlargement of the steel pipe material to cause nitrogen to be absorbed into the surface of the pipe and diffused into the steel solid phase, and applying to the heat-treated pipe material annealing treatment in the range of temperatures in vacuum, inert gas including argon gas or an atmosphere of a gas with a reducing substance including H2 gas added thereto, to result in a decrease of nitrogen concentration gradient.