ASTM A312 Standard Specification for Seamless and Welded Austenitic Stainless Steel Pipes
ASTM A312 Stainless Steel Pipe specifications define high-quality seamless and heavily cold-worked austenitic stainless steel pipes. These pipes are designed for excellent corrosion resistance, high tensile strength, and durability in demanding applications, including chemical processing, oil and gas, and marine industries.
You will find material grade,composition,mechanical properties,Heat treatment, Test and certificate for ASTM A312 Stainless Steel Pipe.
Standard: ASTM A312 / ASME SA312.
Material Grades of ASTM A312
The most commonly used grades under ASTM A312 include:
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TP304 – Most widely used stainless steel grade, offering good corrosion resistance and mechanical properties.
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TP304L – Low-carbon version of 304, better for welding applications.
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TP316 – Improved corrosion resistance due to molybdenum addition, especially in chloride environments.
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TP316L – Low-carbon version of 316, suitable for welding without sensitization issues.
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TP321 – Stabilized with titanium for resistance against intergranular corrosion.
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TP347 – Similar to 321 but stabilized with niobium.
- 254SMO (UNS S31254)
- TP310S
- TP317
- TP317L
ASTM A312 Stainless steel pipe composition
ASTM A312 Mechanical Properties.
ASTM A312 Manufacturing Processes:
ASTM A312 specifies seamless, welded, and heavily cold worked pipes. Seamless pipes are produced by hot extrusion or piercing, while welded pipes are manufactured by welding strips or plates of stainless steel.
ASTM A312 Seamless Pipe
Pipe should be made from stainless steel billet in hot rolling or cold drawn, no any welding process during manufacturing, seamless pipe has better pressure to withstand, annealing solution and pickling finishing condition, applied for high temperature and corrosion environment.
ASTM A312 Welded Pipe
No additional metal using automatic welding process for welded pipe, made from stainless steel strip or plate, both single welding and double welding for option, smail diameter and arge diameter are available, annealing pickling finish.
ASTM A312 Dimensions Scope:
ASTM A312 provides specifications for nominal pipe sizes (NPS) ranging from 1/8 inch to 30 inches, with schedules ranging from SCH 5S to SCH XXS. The standard also covers various wall thicknesses and pipe lengths.
ASTM A312 Heat Treatment
All pipe shall be furnished in the heat-treated condition in accordance with the required heat treating temperature and cooling requirements, pipes shall be individually quenched in water or rapidly cooled by other means (direct quenched).
The pipe shall be free of scale and contaminating exogenous iron particles. Pickling, blasting, or surface finishing is not mandatory when pipe is bright annealed.
ASTM A312 Stainless Steel Pipe Tolerances
Outside Diameter
| Outside Diameter, NPS | Tolerance, Inch |
|---|---|
| 1/8 To 1-1/2, Incl | Over 1/16 Under 1/32 |
| Over 1-1/2 To 4, Incl | Over 1/32 Under 1/32 |
| Over 4 To 8, Incl | Over 1/16 Under 1/32 |
| Over 8 To 18, Incl | Over 3/32 Under 1/32 |
| Over 18 To 26, Incl | Over 1/8 Under 1/32 |
| Over 26 To 34, Incl | Over 5/32 Under 1/32 |
| Over 34 To 48, Incl | Over 3/16 Under 1/32 |
Wall Thickness
| NPS | Wall Thickness Tolerance, % |
|---|---|
| 1/8 To 2-1/2 Incl., All T/D Ratios | Over 20.2 Under 12.5 |
| Over 3 To 18 Incl., T/D Up To 5% Incl. | Over 22.5 Under 12.5 |
| Over 3 To 18, Incl., T/D > 5% | Over 15.0 Under 12.5 |
| 20 And Large, Welded, All T/D Ratios | Over 17.5 Under 12.5 |
| 20 And Large, Seamless, T/D Up To 5% Incl. | Over 22.5 Under 12.5 |
| >20 And Large, Seamless, T/D > 5% | Over 15.0 Under 12.5 |
ASTM A312 Welded And Seamless Pipe Sizes And Chart
ASTM A312 stainless steel pipe sizes and dimensions should conform to ANSI B36.19, nominal pipe size (NPS) ranges from NPS 1/8 [10.29 mm] to NPS 30 [762 mm], Schedule number for wall thickness from Sch 5s to Sch 80s, value stated respective for specific size, average wall and minimum wall pipe are available upon request.
Note over NPS 12 sizes are actual sizes, not like below NPS 12 size values.
| Nominal Size | OD | Wall Thickness, SCHEDULE | |||||
|---|---|---|---|---|---|---|---|
| NPS | DN | Mm | 5S | 10S | 40S | STD | 80S |
| 1∕8 | 6 | 10.3 | – | 1.24 | 1.73 | 1.73 | 2.41 |
| 1∕4 | 8 | 13.7 | – | 1.65 | 2.24 | 2.24 | 3.02 |
| 3∕8 | 10 | 17.2 | – | 1.65 | 2.31 | 2.31 | 3.2 |
| 1∕2 | 15 | 21.3 | 1.65 | 2.11 | 2.77 | 2.77 | 3.73 |
| 3∕4 | 20 | 26.7 | 1.65 | 2.11 | 2.87 | 2.87 | 3.91 |
| 1 | 25 | 33.4 | 1.65 | 2.77 | 3.38 | 3.38 | 4.55 |
| 1 1∕4 | 32 | 42.2 | 1.65 | 2.77 | 3.56 | 3.56 | 4.85 |
| 1 1∕2 | 40 | 48.3 | 1.65 | 2.77 | 3.68 | 3.68 | 5.08 |
| 2 | 50 | 60.3 | 1.65 | 2.77 | 3.91 | 3.91 | 5.54 |
| 2 1∕2 | 65 | 73 | 2.11 | 3.05 | 5.16 | 5.16 | 7.01 |
| 3 | 80 | 88.9 | 2.11 | 3.05 | 5.49 | 5.49 | 7.62 |
| 3 1∕2 | 90 | 101.6 | 2.11 | 3.05 | 5.74 | 5.74 | 8.08 |
| 4 | 100 | 114.3 | 2.11 | 3.05 | 6.02 | 6.02 | 8.56 |
| 5 | 125 | 141.3 | 2.77 | 3.4 | 6.55 | 6.55 | 9.53 |
| 6 | 150 | 168.3 | 2.77 | 3.4 | 7.11 | 7.11 | 10.97 |
| 8 | 200 | 219.1 | 2.77 | 3.76 | 8.18 | 8.18 | 12.7 |
| 10 | 250 | 273.1 | 3.4 | 4.19 | 9.27 | 9.27 | 12.7 |
| 12 | 300 | 323.9 | 3.96 | 4.57 | 9.53 | 9.53 | 12.7 |
| 14 | 350 | 355.6 | 3.96 | 4.78 | – | 9.53 | – |
| 16 | 400 | 406.4 | 4.19 | 4.78 | – | 9.53 | – |
| 18 | 450 | 457.2 | 4.19 | 4.78 | – | 9.53 | – |
| 20 | 500 | 508 | 4.78 | 5.54 | – | 9.53 | – |
| 22 | 550 | 558.8 | 4.78 | 5.54 | – | 9.53 | – |
| 24 | 600 | 609.6 | 5.54 | 6.35 | – | 9.53 | – |
| 26 | 650 | 660.4 | – | – | – | 9.53 | – |
| 28 | 700 | 711.2 | – | – | – | 9.53 | – |
| 30 | 750 | 762 | 6.35 | 7.92 | – | 9.53 | – |
End Preparation of Stainless Steel Pipe
Beveled end A312 stainless steel industrial pipe is used to joint fitting or other connectors, there are different angles and tolerances for special applications, it is easy to welding, and save installing time, cost effective.
Testing And Inspection
- Mechanical Tests
- Grain Size Determinations
- Weld Decay Tests
- Transverse or Longitudinal Tension Test
- Hydrostatic or Nondestructive Electric Test
- Flattening Test (option)
- Radiographic Examination (option)
- Intergranular Corrosion Test (option)
- Weld Decay Test (option)
Reference Documents
- ASTM A999 / A999M – Standard Specification for General Requirements for Alloy and Stainless Steel Pipe
- ASTM A1016 / A1016M – Standard Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes
- ASME B36.10 – Welded and Seamless Wrought Steel Pipe
- ASME B36.19 – Stainless Steel Pipe
ASTM A312 MarkingEach pipe is marked with:
ASTM A312 Standard Grade (e.g., TP304, TP316L) Size and Schedule Heat Number Manufacturer’s Name
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