| 摘要 |
PURPOSE:To obtain a steel for excavating drill pipe excellent in corrosion resistance for use under high temp. and high oxygen pressure, by incorporating each prescribed percentage of C, Si, Mn, P, S, Cu, Cr, Ni, and Mo. CONSTITUTION:The steel for excavating drill pipe has a composition consisting of, by weight, 0.05-0.40% C, 0.05-1.0% Si, 0.1-2.0% Mn, <=0.02% P, <=0.015% S, 0.05-1.0% Cu, 1.0-15.0% Cr, 0.1-1.0% Ni, 0.1-1.5% Mo, and the balance Fe with inevitable impurities. The steel of this invention shows excellent corrosion resistance in a Cl<->-containing aqueous solution under high temp. and high oxygen pressure. Moreover, by applying this steel to aeration liquid mud excavation which is a severe corrosive environment, the use of drill pipes over a longer period is made possible.
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