| 摘要 |
<p>A non-magnetic steel alloy having high corrosion resistance and high strength suitable for use as the material of a drill collar which operates under corrosive conditions, particularly under the conditions which cause stress corrosion cracking, and a drill collar made of the steel alloy. The steel alloy has a composition which essentially consists of: not greater than 0.02% of C, not greater than 2.0% of Si, not greater than 2.0% of Mn, 25 to 40% of Ni, 18 to 30% of Cr, 0.1 to 1.5% of A1, 1.5 to 3.0% of Ti, 0.0005 to 0.020% of Ca, not greater than 0.020% of N and the balance Fe and incidental impurities, and a drill collar made of the steel.</p> |
