API Tubing
Our API Tubing is a high-strength, relatively small-diameter pipe designed to serve as the primary conduit for the passage of oil and gas from the producing formation to the field surface facilities. Manufactured to resist heavy loads, subsurface pressures, and deformations associated with production and workovers.
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Standard: API SPEC 5CT / ISO 11960
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Size Range: OD: 1.050″ – 5-1/2″ (Standard 26.67mm – 114.3mm)
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Tubing Types: Non-upset tubing (NU), External-upset tubing (EUE), Integrated Joint (IJ)
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Grades Available: H40, J55, K55, N80, N80Q, L80 (Type 1, 9Cr, 13Cr), C90, T95, P110, Q125
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End Connections: NUE, EUE, and Premium connections
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Execution: Seamless and Welded
Description
1. Product Overview
Tubing is a relatively small-diameter pipe that is run into a well to serve as a conduit for the passage of oil and gas to the field surface facilities for processing. Tubing must be adequately strong to resist loads and deformations associated with production and workovers. Furthermore, tubing must be sized to support the expected rates of production of oil and gas.
Sizes and Materials
Tubing pipes are manufactured in seamless and welded execution, in the size range of 1.050 to 5 1/2 inches (26.67mm to 114.3mm), and are available in the following material grades: H-40, J-55, K-55, N-80, L-80, C-90, T-95, P-110, Q-125.
End Connections
The main types of connections for tubing pipes are NUE (non-upset), EUE (external upset), and premium connections. Corrosion resistance under sour service conditions is a very important OCTG characteristic, especially for casing and tubing.
2. Dimensions, Lengths & Tolerances
API Tubing Length Ranges
| Range 1 | Range 2 | Range 3 |
|---|---|---|
| 6.10 ~ 7.32 meters | 8.53 ~ 9.75 meters | 11.58 ~ 12.80 meters |
Dimension & End-Finish Matrix
| Label 1 | Label 2 | OD (mm) | WT (mm) | C type of end-finish | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NU T&C | EU T&C | IJ | H40 | J55 | L80 | N80 | C90 | T95 | P110 | |||
| 1.9 | 2.75 | 2.9 | 4 | 48.26 | 3.68 | PNUI | PNUI | PNUI | PNUI | PNUI | PNUI | – |
| 3.65 | 3.73 | 2.76 | 5.08 | PU | PU | PU | PU | PU | PU | PU | ||
| 4.42 | – | – | 6.35 | – | – | P | – | P | P | – | ||
| 2 3/8 | 4 | – | – | 60.32 | 4.24 | PU | PN | PN | PN | PN | PN | – |
| 4.6 | 4.7 | – | 4.83 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | ||
| 5.8 | 5.95 | – | 6.45 | – | – | PNU | PNU | PNU | PNU | PNU | ||
| 6.6 | – | – | 7.49 | – | – | P | – | P | P | – | ||
| 7.35 | 7.45 | – | 8.53 | – | – | PU | – | PU | PU | – | ||
| 2 7/8 | 6.4 | 6.5 | – | 73.02 | 5.51 | PNU | PNU | PNU | PNU | PNU | PNU | PNU |
| 7.8 | 7.9 | – | 7.01 | – | – | PNU | PNU | PNU | PNU | PNU | ||
| 8.6 | 8.7 | – | 7.82 | – | – | PNU | PNU | PNU | PNU | PNU | ||
| 9.35 | 9.45 | – | 8.64 | – | – | PU | – | PU | PU | – | ||
| 10.5 | – | – | 9.96 | – | – | P | – | P | P | – | ||
| 3 1/2 | 7.7 | – | – | 88.9 | 5.49 | PN | PN | PN | PN | PN | PN | – |
| 9.2 | 9.3 | – | 6.45 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | ||
| 10.2 | – | – | 7.34 | PN | PN | PN | PN | PN | PN | – | ||
| 12.7 | 12.95 | – | 9.52 | – | – | PNU | – | PNU | PNU | PNU | ||
| 14.3 | – | – | 10.92 | – | – | P | – | P | P | – | ||
| 15.5 | – | – | 12.09 | – | – | P | – | P | P | – | ||
| 4 | 9.5 | – | – | 101.6 | 5.74 | PN | PN | PN | PN | PN | PN | – |
| 10.7 | 11 | – | 6.65 | PU | PU | PU | PU | PU | PU | – | ||
| 13.2 | – | – | 8.38 | – | – | P | – | P | P | – | ||
| 16.1 | – | – | 10.54 | – | – | P | – | P | P | – | ||
| 4 1/2 | 12.6 | 12.75 | – | 114.3 | 6.88 | PNU | PNU | PNU | PNU | PNU | PNU | – |
| 15.2 | – | – | 8.56 | – | – | P | – | P | P | – | ||
Note: P—plain-end; N—non-upset, with threaded and coupled; U—external-upset, with threaded and coupled; I—whole joint.
Dimension Tolerances
| Pipe Types | Pipe Size (mm) | Tolerances | |
|---|---|---|---|
| Hot Rolled | OD | ≤ 159 | ± 1.0% |
| > 159 | ± 1.20% | ||
| WT | ≤ 20 | ± 12.5% | |
| > 20 | ± 10.0% | ||
| Cold Drawn | OD | ≤ 30 | ± 0.20mm |
| 30-50 | ± 0.30mm | ||
| > 50 | ± 0.8% | ||
| WT | ≤ 3 | +12% , -10% | |
| > 3 | ± 10% | ||
3. Properties & Standards (API Spec 5CT / ISO 11960)
We comply fully with API standard colour coding for coupling and pipe body marking according to respective tubing grades.
Mechanical Properties
| Group | Grade | Type | Total Elongation Under Load (%) | Yield Strength Min (MPa) | Yield Strength Max (MPa) | Tensile Strength Min (MPa) | Hardness HRC (Max) | Hardness HBW (Max) |
|---|---|---|---|---|---|---|---|---|
| 2 | J55 | – | 0.5 | 379 | 552 | 517 | – | – |
| K55 | – | 0.5 | 379 | 552 | 655 | – | – | |
| N80 | 1 | 0.5 | 552 | 758 | 689 | – | – | |
| N80 | Q | 0.5 | 552 | 758 | 689 | – | – | |
| 3 | L80 | 1 | 0.5 | 552 | 655 | 655 | 23 | 241 |
| L80 | 9Cr | 0.5 | 552 | 655 | 655 | 23 | 241 | |
| L80 | 13Cr | 0.5 | 552 | 655 | 655 | 23 | 241 | |
| C90 | 0.5 | 621 | 689 | 689 | 25.4 | 255 | ||
| C95 | – | 0.5 | 655 | 724 | 724 | – | – | |
| T95 | 0.5 | 655 | 724 | 724 | 25.4 | 255 | ||
| P110 | – | 0.6 | 758 | 862 | 862 | – | – | |
| 4 | Q125 | All | 0.65 | 862 | 931 | 931 | – | – |
Chemical Composition (%)
| Standard | Grade | C | Si | Mn | P | S | Cr | Ni | Cu | Mo | V | Als |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| API SPEC 5CT | J55/K55 (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 | 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 |
4. Manufacturing Process
We ensure strict quality control through advanced manufacturing and multi-stage testing processes:
Standard Flow: Ingot heating → Perforation → Rolling and sizing → Cooling → Straightening → NDT (Nondestructive Testing) → End cutting → Coupling thread → Hydraulic test → Painting and thread protecting → Packing.
1. Ingot Heating
Ingot heating is a working procedure which makes the ingot meet the required temperature for hot working. It gives the steel ingot enough plasticity, reduces rolling deformation resistance, and improves internal organization. The process includes low temperature and high temperature stages to ensure uniform inside and outside temperature.
2. Rolling and Sizing
Hot rolling reduces energy consumption and costs significantly. High metal plastic deformation eliminates casting defects and improves the processing performance of the alloy, paving the way for efficient continuous rolling and automation.
3. Cooling
After cooling, the hot rolled steel tube achieves its specific structural range. Compared to traditional processing, this simplifies the production line, saves energy, and grants identical or enhanced mechanical properties.
4. NDT (Nondestructive Testing)
NDT is widely used to inspect and evaluate quality without damaging the pipeline. We utilize heat, sound, and magnetic testing (like UT, RT, VT, and Hydrostatic testing) to detect abnormal inner structures or flaws.
5. Coupling Thread
Threaded joints refer to the pipeline connecting piece with screw threads, the most common connection type in the industry. It makes connection simpler, replacement easier, and vastly saves installation cost while withstanding high pressure.