| 摘要 |
<p>This stainless steel seamless pipe contains, in terms of mass%, C: 0.05% or less, Si: 0.5% or less, Mn: 0.15 to 1.0%, Cr: 13.5 to 15.4%, Ni: 3.5 to 6.0%, Mo: 1.5 to 5.0%, Cu: 2.5% or less, W: 2.5% or less, and N: 0.15% or less so as to satisfy the formula -5.9 × (7.82 + 27C - 0.91Si + 0.21Mn - 0.9Cr + Ni - 1.1Mo - 0.55W + 0.2Cu + 11N) >= 13.0. A high-strength seamless steel pipe having sulfide stress cracking resistance equivalent to composite steel containing about 17% Cr can be manufactured, even using a composition containing a relatively low amount of Cr of about 15%. It is furthermore possible to include one or more elements selected from V: 0.02 to 0.12%, and/or Al: 0.05% or less, and/or Nb: 0.02 to 0.50%, Ti: 0.02 to 0.16%, Zr: 0.50% or less, and B: 0.0030% or less; and/or one or more elements selected from REM: 0.005% or less, Ca: 0.005% or less, and Sn: 0.20% or less.</p> |
