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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 ERW |
Grade A |
Grade B |
| Tensile Strength, min., psi |
48,000 |
60,000 |
| Yield Strength, min., psi |
30,000 |
35,000 |
Chemical Requirements
| Seamless and ERW |
C max % |
Mn max % |
P max % |
S max % |
Grade A |
0.25 |
0.95 |
0.05 |
0.045 |
Grade B |
0.30 |
1.20 |
0.05 |
0.045 |
Testing Requirements
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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.
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Mechanical Tests
| Tensile Test |
Transverse required on ERW for NPS 8 & larger. |
| 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. |
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Degree of Bend |
Diameter of Mandrel |
For Normal A53 Uses |
90 |
12 x dia. of pipe |
For Close Coiling |
180 |
8 x dia. of pipe |
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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
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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%
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Outside DiameterOutside Diameter at any point shall not
vary from standard specified more than:
| NPS |
Over |
Under |
1 1/2 and smaller |
+1/64 |
-1/64 |
For Close Coiling |
+1% |
-1% |
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