Jfe Steel Corporation

Sumitomo Electric Industries, Limited

A.l.m.t. Corporation

Akihide Matsumoto

Atsushi Matsumoto

Takatoshi Okabe

Shinsuke Ide

Shunsuke Toyoda

Hiroshi Nakata

Keiichi Tsuda

Masato Michiuchi

Takehiko Hayashi

Tomoyuki Ishida

Yoshihiro Minato

Ryo Nakazawa

Provided are a hot-rolled steel sheet for an electric resistance welded steel pipe and a method for manufacturing the same, an electric resistance welded steel pipe and a method for manufacturing the same, a line pipe, and a building structure. The hot-rolled steel sheet has a chemical composition containing, by mass %, C: 0.030% or more and 0.20% or less, Si: 0.02% or more and 1.0% or less, Mn: 0.40% or more and 3.0% or less, P: 0.050% or less, S: 0.020% or less, N: 0.0070% or more and 0.10% or less, and Al: 0.005% or more and 0.080% or less, the balance being Fe and incidental impurities, in which N dissolved in steel is contained in an amount of 0.0010% or more and 0.090% or less, and letting a sheet thickness be t, a steel microstructure at a ½t position has an average grain size of 20.0 μm or less.

Hot-rolled steel sheet for electric resistance welded steel pipe and method for manufacturing the same, electric resistance welded steel pipe and method for manufacturing the same, line pipe, and building structure

A metal pipe having an outer diameter of 150 mm to 3,000 mm and a wall thickness of 2 mm to 50 mm, and a method for manufacturing the same. The method includes a pipe-end-portion expansion step of expanding pipe end portions that are located at both ends of a mother pipe and an internal pressure application step that is performed after the pipe-end-portion expansion step and in which the mother pipe is expanded by applying an internal pressure, p, to the entire interior of the mother pipe until the internal pressure, p (MPa), that corresponds to changes in an axial compression amount s (mm), the axial compression amount, s, representing an amount of compression in a pipe axial direction against pipe extreme ends which are the both ends of the mother pipe, becomes a preset maximum internal pressure pmax (MPa), and p and s satisfy a specified formula.

Metal pipe and method for manufacturing metal pipe

Provided is a clad welded pipe or tube that has improved pipe or tube mechanical properties by reducing the width of a weld without its function as a clad pipe or tube being impaired. A clad welded pipe or tube comprises: a first layer made of base metal; and a second layer placed on one surface of the first layer, and made of first cladding metal that is a material different from the base metal, wherein a pipe or tube circumferential length L1 of weld metal at a pipe or tube inner surface and a pipe or tube circumferential length L2 of the weld metal at a pipe or tube outer surface in a weld are each 0.0010 mm or more and 1.0 mm or less, and the base metal is not exposed at a first cladding metal-side surface of the clad welded pipe or tube in the weld.

Clad welded pipe or tube and method of producing same

There is provided an electric resistance welded steel tube having a yield strength of 896 MPa or more, and excellent low-cycle fatigue resistance, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after performing electric resistance welding and a method for manufacturing the same. The steel tube includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N at a specific content. The steel tube has a microstructure that contains 2% to 10% retained austenite and 20% or less martensite on a volume fraction basis, and the remainder being bainite. The yield strength is set to 896 MPa or more and the uniform elongation is set to 9.0% or more.

Electric resistance welded steel tube for coiled tubing and method for manufacturing the same

There is provided a hot-rolled steel sheet suitable for manufacturing an electric resistance welded steel tube, having workability necessary for roll forming and high yield strength, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after electric resistance welding. The steel sheet includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N contained at a specific content. The steel sheet has a microstructure containing 3% to 20% martensite and 10% or less retained austenite on a volume fraction basis, the remainder being bainite. The yield strength is set to 600 MPa or more, the tensile strength is set to 950 MPa or more, and the uniform elongation is set to 7.0% or more.

Hot-rolled steel sheet for coiled tubing

Provided is an electric resistance welded clad steel pipe or tube in which a region where solidification microstructure is formed, i.e. a region in a weld particularly having significant influence on properties, is reduced without impairing its function as a clad pipe or tube. An electric resistance welded clad steel pipe or tube comprises: a first layer made of carbon steel or low-alloy steel as base metal; and a second layer placed on one surface of the first layer, and made of stainless steel or a nickel-containing alloy as cladding metal, wherein the base metal is not exposed at a cladding metal-side surface of the electric resistance welded clad steel pipe or tube in a weld, and no solidification microstructure is contained in each of circular sections of 0.1 mm in radius respectively centered at specific three positions in a plane perpendicular to a pipe or tube longitudinal direction.

Electric resistance welded clad steel pipe or tube and method of producing same

A complex carbonitride powder contains Ti as a main component element and at least one additional element selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, and Si. The complex carbonitride powder includes a plurality of complex carbonitride particles containing Ti and the additional element. The plurality of complex carbonitride particles include a plurality of homogeneous composition particles where average concentrations of Ti and the additional element in each complex carbonitride particle have a difference in a range of greater than or equal to &#x2212;5 atom % and less than or equal to 5 atom % from average concentrations of Ti and the additional element in the whole complex carbonitride powder. A cross-sectional area of the homogeneous composition particles is greater than or equal to 90% of a cross-sectional area of the complex carbonitride particles

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Tokyo, Japan

Akihide Matsumoto