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Seamless steel tubes for oil casing and tubing

Seamless steel tubes for oil casing and tubing application for onshore and offshore Oil & Gas applications in the domains of Exploration, Production and Processing.

Seamless steel tubes for oil casing and tubing application for onshore and offshore Oil & Gas applications in the domains of Exploration, Production and Processing.

Standard:

API SPEC 5CT Standard of American Petroleum Institute

This International Standard is applicable to the following connections in accordance with ISO 10422 or API Spec 5B:

Application:

Seamless steel tubes for oil casing and tubing in oil wells

Model N0.of steel tubes:

J55,N80,L80,P110 etc.

  • short round thread casing (STC);
  • long round thread casing (LC);
  • buttress thread casing (BC);
  • extreme-line casing (XC);
  • non-upset tubing (NU);
  • external upset tubing (EU);
  • integral joint tubing (IJ).

This International Standard specifies the technical delivery conditions for steel pipes (casing, tubing, plain end casing liners and pup-joints) and accessories.

For such connections, this International Standard specifies the technical delivery conditions for couplings and thread protection.

For pipes covered by this International Standard, the sizes, masses, wall thicknesses, grades and applicable end finishes are defined.

This International Standard may also be applied to tubulars with connections not covered by ISO/API standards.

Diamensional tolerances:
Types Outer diameter Wall thickness
Cold-rolled tubes Tube sizes(mm) Tolerances(mm) Tolerances(mm)
<114.3 ±0.79 -12.5%
≥114.3 -0.5%,+1%
Mechanical properties of API SPEC 5CT:
Models of steel tubes
Tensite strength(MPa)
Yield strength(MPa)
Hardness
J55 ≥517 379~552 -
K55 ≥517 ≥655 -
N80 ≥689 552~758 -
L80(13Cr) ≥655 552~655 ≤241HB
P110 ≥862 758~965 -

Chemical composition of API SPEC 5CT:
Models of steel tubes Chemical compositions (%)
C Si Mn P S Cr Ni Cu Mo V Als
J55K55

(37Mn5)
0.34~0.39 0.20~0.35 1.25~1.50 ≤0.020 ≤0.015 ≤0.15 ≤0.20 ≤0.20 - - ≤0.020
N80

(36 Mn2V)
0.34~0.38 0.20~0.35 1.45~1.70 ≤0.020 ≤0.015 ≤0.15 - - - 0.11~0.16 ≤0.020
L80(13Cr) 0.15~0.22 ≤1.00 0.25~1.00 ≤0.020 ≤0.010 12.0~14.0 ≤0.20 ≤0.20 - - ≤0.020
P110

(30CrMo)
0.26~0.35 0.17~0.37 0.40~0.70 ≤0.020 ≤0.010 0.80~1.10 ≤0.20 ≤0.20 0.15~0.25 ≤0.08 ≤0.020



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