Importance

Loading Importance Indicators...

Abstract

A method of producing steel for a steel pipe excellent in sour-resistance performance comprises controlling the amount of Ca addition charged into a molten steel in a ladle according to a N content in the molten steel prior to Ca addition. Non-metallic inclusions in the steel are mainly composed of Ca, Al, 0 and S, and a CaO content in the inclusions is in the range of 30 to 80%, the ratio of the N content in the steel to the CaO content in the inclusions satisfying equation (1), and a CaS content in the inclusions satisfies equation (2),

description='In-line Formulae' end='lead'0.28≦[N]/(% CaO)≦2.0  (1)description='In-line Formulae' end='tail'

description='In-line Formulae' end='lead'(% CaS)≦25%  (2)description='In-line Formulae' end='tail'

where [N] represents the mass content (ppm) of N in the steel, (% CaO) represents the mass content (%) of CaO in the inclusions, and (% CaS) represents the mass content (%) of CaS in the inclusions.

Loading the Abstract Image...

First Claim