Nkk Corporation

Kobe Steel, Ltd.

Exxonmobil Upstream Research Company

Kabushiki Kaisha Kobe Seiko Sho

Moriyasu Nagae

Shigeru Endo

Motokiyo Itoh

Narasimha-Rao Venkata Bangaru

Jayoung Koo

Mitsuhiro Okatsu

Hyun-Woo Jin

Douglas Paul Fairchild

Adnan Ozekcin

Raghavan Ayer

Shinichi Kakihara

Danny Lee Beeson

Toshihiko Nakano

Douglas S Hoyt

Shouzou Naruse

Takeshi Sugino

James B LeBleu, Jr

Masato Konishi

Osamu Hirano

Kazuyoshi Ume

A steel composition and method from making a dual phase steel therefrom. The dual phase steel may have carbon of about 0.05% by weight to about 0.12 wt %; niobium of about 0.005 wt % to about 0.03 wt %; titanium of about 0.005 wt % to about 0.02 wt %; nitrogen of about 0.001 wt % to about 0.01 wt %; silicon of about 0.01 wt % to about 0.5 wt %; manganese of about 0.5 wt % to about 2.0 wt %; and a total of molybdenum, chromium, vanadium and copper less than about 0.15 wt %. The steel may have a first phase consisting of ferrite and a second phase having one or more of carbide, pearlite, martensite, lower bainite, granular bainite, upper bainite, and degenerate upper bainite. A solute carbon content in the first phase may be about 0.01 wt % or less.

Low yield ratio dual phase steel linepipe with superior strain aging resistance

An abrasion-resistant welded steel pipe having a base plate and a weld metal: consists essentially of 0.05 to 0.2 wt. % C, 0.5 to 2 wt. % Si, 0.5 to 2.5 wt. % Mn, 0.02 to 2 wt. % Al, the balance being Fe and inevitable impurities; and the steel pipe has a Vickers hardness of at least 200. The abrasion-resistant welded steel pipe can further contain at least one element selected from the group consisting of 0.05 to 1 wt. % Cu, 0.05 to 2 wt. % Ni, 0.05 to 2 wt. % Cr, 0.05 to 1 wt. % Mo, 0.005 to 0.1 wt. % Nb, 0.005 to 0.1 wt. % V, 0.005 to 0.1 wt. % Ti, 0.0003 to 0.002 wt. % B.

Abrasion-resistant welded steel pipe

Disclosed is a gas-shield arc welding method in which chemical components of base material and weld material (gas-shield arc welding wire), chemical component ranges of weld metal based on the base material and the weld material, especially, difference (.DELTA.(Cu+Ni), .DELTA.Mo) of Cu, Ni and Mo between the weld metal and the base material, and welding conditions are limited for the purpose of improvement preferential corrosion resistance, toughness and crack resistance of the weld metal in circumferential welding of a pipe exposed into a corrosion environment including CO.sub.2.

Method for gas-shield arc welding of a pipe and weld wire for use in the

Chemical compositions of a base metal and a high cellulose type welding electrode are regulated within predetermined ranges, so that the chemical composition of the weld metal obtained from the welding can be regulated within a predetermined range. Particularly, with respect to the weld metal, the Mo content (Mo)1 in the weld metal and the Mo content (Mo)2 in the base metal are regulated such that the difference between the both contents .DELTA.Mo (=(Mo)1-(Mo)2) is 0.03% or more, and PCM is 0.30% or less, where PCM is defined as follows: PCM=(C)+(Si)/30+(Mn)/20+(Cu)/20+(Ni)/60+(Cr)/20+(Mo)/15+(V)/10+5(B). Here, (M) denotes a content (weight %) of a component M in the weld metal. On the other hand, a coating flux of the high cellulose type coated electrode contains relative to the total amount of the coating flux, 0.1 to 7.0% of MgO, 7 to 25% of iron oxides (in FeO equivalent), 8 to 19% of TiO.sub.2, 10 to 30% of SiO.sub.2 and 5 to 27% of Mn, and a core wire and/or the coating flux includes 0.06 to 1.10% of Mo relative to the total amount of the welding electrode. A ratio of the weight of the coating flux to the weight of the welding electrode being 0.10 to 0.19. By this, preferential corrosion resistance, toughness and crack resistance can be improved in the weld metal of a girth weld zone of a pipe which might be exposed in a corrosion environment containing CO.sub.2.

Girth-welding process for a pipe and a high cellulose type coated

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Tokyo, Japan

Moriyasu Nagae