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Specification A106 covers Seamless carbon steel nominal wall pipe for high-temperature service, suitable for bending, flanging and similar forming operations. NPS 1 1/2 and under may be either hot finished or cold drawn. NPS 2 and larger shall be hot finished unless otherwise specified. Surface finish standards are outlined in the specification. Purchaser may specify NDE in lieu of hydrostatic test or neither. Unless otherwise specified, pipe is furnished with plain ends.
Mechanical Properties - Tensile Requirements
| Seamless and ERW |
Grade A |
Grade B |
Grade C |
Tensile Strength, min., psi |
48,000 |
60,000 |
70,000 |
Yield Strength, min, psi |
30,000 |
35,000 |
40,000 |
Chemical Requirements
| Seamless and ERW |
Grade A |
Grade B |
Grade C |
Carbon max. % |
0.25 |
0.30 |
0.35 |
Manganese % |
0.27 - 0.93 |
0.29 - 1.06 |
0.29 - 1.06 |
Phosphorus, max % |
0.035 |
0.035 |
0.035 |
Sulfer, max. % |
0.035 |
0.035 |
0.035 |
Silicon, min. % |
0.10 |
0.10 |
0.10 |
Testing Requirements
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Hydrostatic Testing
Inspection test pressures produce a stress in the pipe wall equal to 60% of specified minimum yield strenth (SMYS) at room temperature. Maximum Pressures are not to exceed 2500 psi for NPS 3 and under, and 2800 spi for the larger sizes. Pressure is mantained for not less than 5 seconds.
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Mechanical Tests
| Tensile Test |
NPS 8 and larger - either transverse or longitudinal acceptable. |
| Flattening Test |
NPS 2 and larger. |
| Bending Test (cold) |
NPS 2 and under. |
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Degree of Bend |
Diameter of Mandrel |
For Normal A106 Uses |
90 |
12 x dia. of pipe |
For Close Coiling |
180 |
8 x dia. of pipe |
Number of Tests
| |
NPS |
On One Length
From Each Lot of |
Tensile |
5 and smaller
6 and larger |
400 or less
200 or less |
Bending |
2 and smaller |
400 or less |
Flattening |
2 through 5
6 and over |
400 or less
200 or less |
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