STEEL MATERIAL, AND OIL-WELL STEEL PIPE FOR EXPANSION

WIPO Patent Application WO/2016/052271

A1

This steel material has a chemical composition which includes, in mass%, 0.6-1.8% of C, 0.05-1.00% of Si, over 25.0% but not more than 45.0% of Mn, 0.003-0.06% of Al, not more than 0.03% of P, not more than 0.03% of S, 0.5-3.0% of Cu, not more than 0.10% of N, 0-2.0% of V, 0-3.0% of Cr, 0-3.0% of Mo, 0-1.5% of Ni, 0-0.5% of Nb, 0-0.5% of Ta, 0-0.5% of Ti, 0-0.5% of Zr, 0-0.005% of Ca, 0-0.005% of Mg, 0-0.01% of REM, and 0-0.015% of B, the remainder comprising Fe and impurities, and which satisfies [0.6