Mitsubishi Heavy Industries Limited

Sumitomo Metal Industries, Inc.

National Institute for Materials Science

Masayuki Kondo

Masahiro Kobayashi

Hirokazu Okada

Nobuhiko Nishimura

Susumu Tsukamoto

Masashi Ozaki

Fujio Abe

Akira Shiibashi

Masaaki Tabuchi

A welded joint of a tempered martensitic heat resisting steel includes a fine-grained heat affected zone of weldment of a heat resisting steel having a tempered martensite structure which exhibits a creep strength of 90% or more of the creep strength of the base metal thereof. The welded joint is inhibited in the formation of the fine-grained HAZ exhibiting a significantly reduced creep strength.

Welded joint of tempered martensite based heat-resistant steel

A heat resistant steel can be produced at a low cost and has an excellent high temperature strength. A high-strength heat-resistant steel is provided which comprises carbon in an amount of 0.06 to 0.15% by weight, silicon in an amount of 1.5% by weight or less, manganese in an amount of 1.5% by weight or less, vanadium in an amount of 0.05 to 0.3% by weight, chromium in an amount of 0.8% by weight or less, molybdenum in an amount of 0.8% by weight or less, at least one selected from niobium, titanium, tantalum, hafnium, and zirconium in an amount of 0.01 to 0.2% by weight, nitrogen in an amount of 20 to 200 ppm, and the balance being iron and unavoidable impurities, and the high-strength heat-resistant steel comprising a bainite structure.

High-strength heat-resistant steel, process for producing the same, and process for producing high-strength heat-resistant pipe

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Tsukuba, Japan

Masayuki Kondo