Sumitomo Metal Industries, Inc.

Toyota Jidosha Kabushiki Kaisha

Nippon Steel Sumitomo Metal Corporation

Mitsuo Miyahara

Masaaki Igarashi

Tomohiko Omura

Kazuhiro Ogawa

Kenji Imanishi

Hiroyuki Semba

Kazuhiko Ogawa

Shinji Shibata

Haruhiko Kajimura

Kiyoko Takeda

Masao Koike

Tomoyuki Sugino

Katsuhiko Maruyama

Kenji Higuchi

Naoki Kitagawa

Hitoshi Taguchi

Mitsuaki Watanabe

Shinnichirou Hiramatsu

An austenitic stainless steel for use in a hydrogen gas atmosphere comprises, in mass %, C: 0.10% or less, Si: 1.0% or less, Mn: 0.01 to 30%, P: 0.040% or less, S: 0.01% or less, Cr: 15 to 30%, Ni: 5.0 to 30%, Al: 0.10% or less, N: 0.001 to 0.30% with the balance Fe and inevitable impurities. An X-ray (111) integration intensity of a cross section along the direction rectangular to the working direction is five times that in a random direction or less, and the X-ray integration intensity ratio of a cross section along the working direction satisfies I(220)/I(111)&#x2266;10. The high strength steel can also contain one or more of the groups of Mo and W; V, Nb, Ta, Ti, Zr and Hf; B; Cu and Co; Mg, Ca, La, Ce, Y, Sm, Pr and Nd.

Austenitic stainless steel for hydrogen gas and a method for its manufacture

Provided is a low alloy steel for high-pressure hydrogen gas environments, which contains, by mass percent, C: 0.15 to 0.60%, Si: 0.05 to 0.5%, Mn: 0.05 to 3.0%, P: not more than 0.025%, S: not more than 0.010%, Al: 0.005 to 0.10%, Mo: 0.5 to 3.0%, V: 0.05 to 0.30%, O (oxygen): not more than 0.01%, N: not more than 0.03%, and the balance Fe and impurities, and has tensile strength of not less than 900 MPa. This low alloy steel desirably contains B of 0.0003 to 0.003%, but in this case, N is limited to not more than 0.010%. It is desirable to contain at least one among Cr, Nb, Ti, Zr, and Ca. The contents of Mo and V desirably satisfy the following formula (1):[Mo(%)]&#xb7;[V(%)]&#x2267;0.32&#x2003;&#x2003;(1).

Low alloy steel for high-pressure hydrogen gas environment and container for high-pressure hydrogen

A high-strength stainless steel, having good mechanical properties and corrosion resistance in a high-pressure hydrogen gas environment, is used as a container or other device for high-pressure hydrogen gas, and consists of, by mass %, C: not more than 0.04%, Si: not more than 1.0%, Mn: 7 to 30%, Cr: 15 to 22%, Ni: 5 to 20%, V: 0.001 to 1.0%, N: 0.20 to 0.50% and Al: not more than 0.10%, and the balance Fe and impurities. Among the impurities, P is not more than 0.030%, S is not more than 0.005%, and Ti, Zr and Hf are not more than 0.01% respectively, and the contents of Cr, Mn and N satisfy the relationship, 2.5Cr+3.4Mn&#x2266;300N. The weld metal of the welded joint of the container or other device made of the said stainless steel satisfies the relationship, &#x2212;11&#x2266;Nieq&#x2212;1.1&#xd7;Creq&#x2266;&#x2212;8.

Stainless steel for high-pressure hydrogen gas

A high-strength stainless steel, having good mechanical properties and corrosion resistance in a high-pressure hydrogen gas environment, and excellent in stress corrosion cracking resistance, and a container or other device for high-pressure hydrogen gas, which is made of the said stainless steel, are provided. The stainless steel is characterized in that it consists of, by mass %, C: not more than 0.02%, Si: not more than 1.0%, Mn: 3 to 30%, Cr: more than 22% but not more than 30%, Ni: 17 to 30%, V: 0.001 to 1.0%, N: 0.10 to 0.50% and Al: not more than 0.10%, and the balance Fe and impurities. Among the impurities, P is not more than 0.030%, S is not more than 0.005%, and Ti, Zr and Hf are not more than 0.01% respectively, and the contents of Cr, Mn and N satisfy the following relationship [1]:5Cr+3.4 Mn&#x2266;500 N&#x2003;&#x2003;[1].

A weld joint having a base material and a weld metal both of an austenitic steel, wherein the weld metal has a chemical composition, in mass %, that C: 0.04% or less, Si: 1.0% or less, Mn: 3% or less, P: 0.02% or less, S: 0.005% or less, Cr: 15 to 25%, Ni: 30% or more, Mo: 10% or less, Nb: 2.5 to 5%, Al: 3.0% or less, Ti: 0.5% or less, and the balance: Fe and inevitable impurities, the contents of Al and Ti satisfying the following: (Ti+Al)&#x3e;Nb/8. The weld joint is a high strength austenitic steel weld joint which exhibits excellent toughness at a low temperature and excellent resistance to hydrogen embrittlement, which are required for a piping and a vessel for high pressure hydrogen, particularly also in a welded zone.

Welded joint made of an austenitic steel

An austenitic stainless steel with minimized deformation by heating and cooling treatment after cold working, which consists of, % by mass, C: 0.03% or less, Si: 2 to 4%, Mn: 0.1 to 2%, P: 0.03% or less, S: 0.03% or less, Ni: 9 to 15%, Cr: 15 to 20%, N: 0.02 to 0.2%, Nb: 0.03% or less, each of Mo and Cu or a total of Mo and Cu: 0.2 to 4%, and the balance Fe and impurities, and satisfies the following formulas (1) and (2). This steel can also have good weldability when the following formula (3) is also satisfied in addition to the formulas (1) and (2);16.9+6.9Ni+12.5Cu&#x2212;1.3Cr+3.2Mn+9.3Mo&#x2212;205C&#x2212;38.5N&#x2212;6.5Si&#x2212;120Nb&#x2267;40&#x2003;&#x2003;(1)450&#x2212;440(C+N)&#x2212;12.2Si&#x2212;9.5Mn&#x2212;13.5Cr&#x2212;20(Cu+Ni)&#x2212;18.5Mo&#x2266;&#x2212;90&#x2003;&#x2003;(2)8.2+30(C+N)+0.5Mn+Ni&#x2212;1.1(1.5Si+Cr+Mo)+2.5Nb&#x2266;&#x2212;0.8&#x2003;&#x2003;(3)

Austenitic stainless steel

A ferritic stainless steel which exhibits improved formability and which is especially useful for making 950.degree. C. or 1000.degree. C. exhaust manifolds is disclosed, the steel composition thereof consisting essentially of, on the basis of weight:

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Kobe, Japan

Mitsuo Miyahara