API non-upset (NUE) tubing is put to use much less than EUE tubing.

The cost of NUE is usually just a bit less than EUE, along with the joint strength is substantially less. The coupling joint diameter of NUE is less than EUE, which provides certain benefits in cases where clearance is small.

API NUE joints are available in sizes of 1.050 to 4.500 inch.

Specifications

Tolerances

Mechanical Properties

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Inspection

Physical properties are checked and each length hydrostatically tested, normally to only 3,000 psi in the plain end (unthreaded) condition. The following are also checked:

• Dimensions
• Weights
• Straightness
• Lengths

Part of this inspection is to drift all lengths.
Despite all the American Petroleum Institute (API) specifications and testing, some tubing defects are still found after delivery; thus, some operators do further inspection.

Inspection Method

• Size and surface inspection
• NDT and pressure test and third party certication
• Hydrostatic
• Drifting test
• Physical and chemicail analysis
• Hardness and pressure test.
• Electromagnetic
• Magnetic particle
• Ultrasonic