ASTM A312 Welded Stainless Steel Tube Schedule 5S To 40S For Water Treatment Applications
The ASTM A312 Welded Stainless Steel Tube is manufactured in accordance with the internationally recognized ASTM A312 standard, which covers seamless, welded, and heavily cold worked welded austenitic stainless steel pipes. This welded tube is produced by roll forming stainless steel coil into a cylindrical shape and longitudinally welding the seam using advanced TIG (GTAW) or laser welding technology. After welding, the tube is fully annealed to restore corrosion resistance and mechanical properties. It offers a cost-effective, reliable solution for corrosive and high-temperature service in chemical processing, petrochemical, power generation, and general industrial applications.
| Parameter | Details |
|---|---|
| Standards | ASTM A312 / ASME SA312 |
| Available Grades | 304, 304L, 316, 316L, 321, 347, 310S |
| Outer Diameter | 6 mm – 1219 mm (1/8″ – 48″ NPS) |
| Wall Thickness | 0.5 mm – 12.7 mm (Schedule 5S, 10S, 40S) |
| Length | 3m, 6m, or custom lengths up to 12m |
| Welding Process | TIG (GTAW), Laser, or Plasma |
| Weld Seam | Single longitudinal seam |
| Heat Treatment | Annealed after welding (per ASTM A312) |
| Surface Finish | Pickled, passivated, mill finish, or polished |
| End Finish | Plain ends, beveled ends, or grooved |
| Grade | C ≤ | Si ≤ | Mn ≤ | P ≤ | S ≤ | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|
| 304 | 0.08 | 0.75 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-10.5 | – |
| 304L | 0.03 | 0.75 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-12.0 | – |
| 316 | 0.08 | 0.75 | 2.00 | 0.045 | 0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 |
| 316L | 0.03 | 0.75 | 2.00 | 0.045 | 0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 |
Composition per ASTM A312.
| Grade | Tensile Strength (MPa) min | Yield Strength (MPa) min | Elongation (%) min | Hardness (HB) max |
|---|---|---|---|---|
| 304 | 515 | 205 | 35 | 201 |
| 304L | 485 | 170 | 35 | 201 |
| 316 | 515 | 205 | 35 | 217 |
| 316L | 485 | 170 | 35 | 217 |
Tested in accordance with ASTM E8 / E8M.
ASTM A312 Compliant – Meets strict international standards
Cost-Effective – Lower cost than seamless pipe
Large Diameter – Available up to 48″ (1219 mm)
Annealed After Welding – Restores corrosion resistance
100% Hydrostatic Tested – Per ASTM A312 requirements
Consistent Wall Thickness – High dimensional accuracy
Wide Grade Selection – 304L, 316L, 321, 347, 310S
Good Weldability – Easy to join with standard methods
| Parameter | Tolerance |
|---|---|
| Outer diameter | ±0.4 mm for OD ≤ 48.3 mm; ±0.8% for larger |
| Wall thickness | ±12.5% |
| Length (fixed) | +0 / -3 mm |
| Straightness | 0.2% of total length |
| NPS (inch) | OD (mm) | Schedule 5S (mm) | Schedule 10S (mm) | Schedule 40S (mm) |
|---|---|---|---|---|
| 1/2″ | 21.3 | 1.65 | 2.11 | 2.77 |
| 1″ | 33.4 | 1.65 | 2.77 | 3.38 |
| 2″ | 60.3 | 1.65 | 2.77 | 3.91 |
| 4″ | 114.3 | 1.65 | 3.05 | 6.02 |
| 6″ | 168.3 | 1.65 | 3.40 | 7.11 |
| 8″ | 219.1 | 1.65 | 3.76 | 8.18 |
Chemical & Petrochemical
Process piping systems
Heat exchanger shells
Utility water and steam lines
Food & Beverage
Dairy process lines
Brewery transfer lines
Sanitary utility systems
Pharmaceutical
Purified water distribution
Clean steam lines
Water Treatment
Potable water systems
Reverse osmosis feed lines
Power Generation
Cooling water lines
Low-pressure steam lines
Oil & Gas
Utility water systems
Fire protection mains
| Property | Welded (ASTM A312) | Seamless (ASTM A312) |
|---|---|---|
| Cost | Lower | Higher (30-50%) |
| Max Diameter | 48″ (1219 mm) | 24″ (610 mm) |
| Weld Seam | Present – NDT verified | None |
| High Pressure Service | Moderate | High |
| Availability | Stock sizes widely available | Longer lead times |
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