| 摘要 |
A flexible tubular structure for oil exploitation comprising a polymeric internal barrier layer and at least one metallic reinforcing layer comprising at least one elongated steel element having a non-round cross-section and having as steel composition:
a carbon content ranging from 0.20 weight percent to 1.00 weight percent, a silicon content ranging from 0.05 weight percent to 2.0 weight percent,
a manganese content ranging from 0.40 weight percent to 1.0 weight percent, a chromium content ranging from 0.0 weight percent to 1.0 weight percent,
a sulfur and phosphor content being individually limited to 0.025 weight percent, contents of nickel, vanadium, aluminium or other micro-alloying elements all being individually limited to 0.5 weight percent,
the remainder being iron,
said steel having martensitic structure that comprises martensitic grains, wherein a fraction of at least 10 volume percent of martensitic grains is oriented. |
