Patent ID: 6723453
Filing Date: 2004-04-20
Classification: C21D,C22C,Y10T

Abstract:
A welded steel pipe having excellent hydroformability having a composition comprising, on the basis of mass percent:about 0.05% to about 0.2% C; about 0.01% to about 0.2% Si; about 0.2% to about 1.5% Mn; about 0.01% to about 0.1% P; about 0.01% or less of S; about 0.01% to about 0.1% Al; about 0.001% to about 0.01% N; and the balance being Fe and incidental impurities, wherein the welded steel pipe has a tensile strength of at least about 400 MPa and less than 590 MPa, and an nÃ—r product of an n-value and an r-value is at least about 0.22.