To provide a thin high strength electric resistance welded pipe in which t/D is reduced at a low cost.
Disclosed is a high strength electric resistance welded line pipe produced through the process of cold roll molding, electric resistance welding, seam heat treatment and sizing from a hot coil, and in which the outside diameter is 200 to 610 mm and the ratio of thickness/outside diameter (t/D) is 2%. The pipe has an acicular-ferrite metallic structure with the average crystal grain size of 5 m, and in which the tensile strength in the circumferential direction after flattening is 700 N/mm2, a 0.5% proof stress is 550 N/mm2, and the occupancy area ratio of the oxide in the electric resistance welding abutted part is 0.1%. The line pipe comprises, as desirable components, 0.04 to 0.08% C, 0.04 to 0.08% Nb, 0.05 to 0.1% V, 0.1 to 0.5% Ni, 0.1 to 0.5% Cu, 0.05 to 0.20% Mo and 0.01 to 0.03% Ti, and in which the contents of Ni, Cu and Mo satisfy 1.03Mo+Ni+Cu0.8.
KOYUMIBA MOTOFUMI
OGATA TOSHIYUKI
ASAHI HITOSHI
| JPH1112682A | 1999-01-19 | |||
| JPH09316599A | 1997-12-09 | |||
| JPS62151545A | 1987-07-06 | |||
| JP2005290546A | 2005-10-20 | |||
| JP2005290526A | 2005-10-20 |
Hisataka Tanaka