| abstract |
low alloy steel tube for oil well This is a low alloy steel tube for an oil well, and the steel tube has high strength and stability, exhibiting excellent resistance to ssc. the low alloy steel tube for an oil well has a chemical composition that contains not less than 0.15%, but less than 0.30% of c, 0.05 to 1.00% of itself, 0.05 to 1.00% of mn, not more than 0.030% of p, not more than 0.0050% of s, 0.005 to 0.100% of al, not more than 0.005% of o, not more than 0.007% of n, no less than 0.10%, but less than 1.00% cr, more than 1.0%, but not more than 2.5% by hand, 0.01 to 0.30% of v, 0.002 to 0.009% of ti, 0 to 0.050% of nb, 0 to 0.0050% of b and 0 to 0.0050% of ca, with the remainder consisting of faith and impurities. the chemical composition satisfies mo / cr (greater than equal) 2.0, has a crystal grain size number of 7.0 or more, contains 50 or more cementite grains that have diameters equivalent to a 200 nm circle or more per 100 (mi) m2 of matrix, has a numerical density of alloy carbides of the m2c type of 25 per (mi) m2 or more, and has a flow limit of 758 mpa or more. |