General Description

Specification A53 covers Seamless and Welded, black and hot-dipped galvanized nominal (average) wall pipe for coiling, bending, flanging, and other special purposes and is suitable for welding.

Mechanical Properties – Tensile Requirements

Seamless and ERWGrade AGrade B
Tensile Strengh, min., psi48,00060,000
Yield Strength, min., psi30,00035,000

Chemical Requirements

Seamless and ERWC max %Mn Max %P max %S max %
Grade A0.250.950.050.045
Grade B0.301.200.050.045

Testing Requirements

Hydrostatic Testing

Hydrostatic inspection test pressures for plain end and threaded and coupled pipe are specified. Hydrostatic pressure shall be maintained for not less than 5 seconds for all sizes of Seamless and Electric Resistance Weld Pipe.

Mechanical Tests

Tensile Test – Transverse required on ERW for NPS 8 & lager
Flattening Test – For NPS 2 and larger, STD and XS walls. (Not required for XXS pipe)
Bending Test (cold) – For NPS 2 and under, XS wall and under / For NPS 1 1/4 and under, under XXS wall.

Degree of BendDiameter of Mandrel
For Normal A53 Uses9012 X dia. of Pipe
For Close Coiling1808 X dia. of Pipe

Number of Tests

Seamless and Electric Resistance Weld – Bending, flattening, tensile on one length of pipe from each lot of 500 lengths, of each pipe size.

Permissible Variations

Wall Thickness

The minimum wall thickness at any point shall not be more than 12.5% under the nominal thickness specified.

Weights per Foot

Plus or Minus 10%

Outside Diameter

Outside Diameter at any point shall not vary from standard specified more than:

1 1/2 and smaller+1/64-1/64
For Close Coiling+1%-1%