Sumitomo Metal Industries, Inc.

Other

Mitsubishi Jukogyo Kabushiki Kaisha

Kaori Miyata

Masaaki Igarashi

Kunio Kondo

Tomohiko Omura

Fujimitsu Masuyama

Takahiro Kushida

Nobuyoshi Komai

Tomomitsu Yokoyama

Hiroyuki Senba

A heat-resistant steel contains 0.1-3 mass % of Cr and satisfies the following equation: 0.1&lE;Nb&plus;Mo&plus;V and MX-type complex precipitates formed inside microcrystalline grains contain 30 mass % or more of Mo and 7 mass % or more of Nb. Also provided is a process for producing the alloy steel product involving casting, forging, hot rolling, normalizing, optionally direct quenching, cooling at a predetermined cooling rate, and tempering.

Heat resistance Cr-Mo alloy steel

A low alloy steel for oil country tubular well which has a yield stress of 110 ksi or above, and excellent sulfide stress cracking resistance. The low alloy steel comprises, by weight, 0.2 to 0.35% carbon, 0.2 to 0.7% chromium, 0.1 to 0.5% molybdenum, 0.1 to 0.3% vanadium, 0 to 0.5% silicon, 0 to 1% manganese, 0 to 0.1% aluminum, 0 to 0.1% niobium, 0 to 0.05% titanium, 0 to 0.005% boron, 0 to 0.1% zirconium, 0 to 1% tungsten, 0 to 0.01% calcium, 0.025% or less phosphorus, 0.01% or less sulfur, 0.01% or less nitrogen, and 0.01% or less oxygen. The low alloy steel further comprises a total amount of precipitated carbides between about 2 to 5% by weight, and a ratio of the MC type carbide to the total amount of the precipitated carbides is between about 8 to 40% by weight.

Low alloy steel for oil country tubular goods and method of making

A low Mn-low Cr ferritic heat resistant steel consisting essentially of, in weight %: 0.02-0.20% C, up to 0.7% Si, less than 0.1% Mn, up to 0.8% Ni, 0.8-3.5% Cr, 0.01-3.0% W, 0.1-0.5% V, 0.01-0.20% Nb, 0.001-0.05% Al, 0.0005-0.05% Mg, 0.0005-0.01% B, less than 0.05% N, up to 0.03% P, up to 0.015% S, 0.001-0.05% Ti and the balance Fe and incidental impurities, wherein the B content is defined so as to satisfy the following formula (14/11)B&gt;N-N(V/51)/{(C/12)+(N/14)}-N(Nb/93)/{(C/12)+(N/14)}-N(Ti/48)/{C/12 )+(N/14)}. The steel can further contain optionally 0.01-1.5% Mo, and/or one or more elements selected from the group consisting of 0.01-0.2% La, 0.01-0.2% Ce, 0.01-0.2% Y, 0.01-0.2% Ca, 0.01-0.2% Ta and 0.01-0.2% Zr. The steel can be used in place of the austenitic steels or high Cr ferritic steels, since it has remarkably improved toughness, workability and weldability, and excellent creep properties at elevated temperatures.

Low Mn-low Cr ferritic heat resistant steel excellent in strength at

The present invention discloses high chromium ferritic heat-resistant steel which has remarkable properties that the base metal and welded joints of the steel both exhibit excellent long term creep strength at elevated temperatures over 600.degree. C. excellent resistance to steam oxidation, and excellent toughness at room temperatures. The chemical composition of main elements of the steel of the invention is as follows:

High chromium ferritic heat-resistant steel

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Osaka, Japan

Kaori Miyata