|
ASTM A778 Welded Unannealed Stainless Steel Pipe TP304L/TP316L for Low-Moderate Temperature and Corrosive Service
| MOQ: | 5Ton |
| Price: | Based on grade, size, surface, processing, quantity and current raw material market price. |
| Standard Packaging: | Standard seaworthy export packing with bundles, waterproof wrapping, pallets or wooden cases. |
| Delivery Period: | 7-15 |
| Payment Method: | L/C,D/A,D/P,T/T,Western Union |
| Supply Capacity: | Stock supply, regular production and custom manufacturing available. |
Shaanxi Shangyou Stainless Steel Co., Ltd. supplies ASTM A778 welded unannealed stainless steel pipe for global distributors, fabricators, and industrial end-users requiring cost-effective welded tubular products for low and moderate temperature corrosive service. Produced to ASTM A778/A778M, this specification covers straight seam and spiral butt seam welded unannealed austenitic stainless steel tubular products where heat treatment is not necessary for corrosion resistance.
ASTM A778 is the standard specification for welded unannealed austenitic stainless steel tubular products. Unlike ASTM A312, which requires post-weld annealing, ASTM A778 pipes are furnished unannealed—meaning the product is supplied in the as-welded condition without the additional heat treatment step. This makes A778 significantly more cost-effective than A312 for applications where the heat-affected zone does not pose a corrosion risk. The standard covers five austenitic grades, with TP304L and TP316L being the most common. The pipe is manufactured from flat-rolled steel sheet, coil, or plate by a shielded arc-welding process, with welds made by manual or automatic electric-welding process. Users requiring post-weld heat treatment or radiographic examination are referred to ASTM A312, A358, or A409 as applicable.
| Dimension | Specification |
|---|---|
| Product Name | ASTM A778 Welded Unannealed Stainless Steel Pipe |
| Product Alias | Unannealed Welded Pipe / A778 Stainless Pipe / Welded Unannealed Tubing / Commodity Stainless Pipe / As-Welded Pipe |
| Material Type | Austenitic Stainless Steel (Straight/Spiral Seam, Unannealed) |
| Key Feature | Supplied unannealed (no post-weld heat treatment); cost-effective; commodity product; NPS 3-48; straight seam or spiral butt seam |
| Common Grades | TP304L, TP316L (plus other austenitic grades per Table 1) |
| Chemical Composition (TP316L) | Cr 16.0-18.0% / Ni 10.0-14.0% / Mo 2.0-3.0% / C ≤ 0.035% / Fe Balance |
| Mechanical Properties (TP316L) | Tensile ≥485 MPa / Yield ≥170 MPa / Elongation ≥35% |
| Manufacturing Process | Flat-Rolled Coil/Sheet/Plate → Forming → Shielded Arc Welding (Straight or Spiral Seam) → Sizing → Hydro/NDE Testing (No Annealing) |
| Surface Finish | Mill Finish / Pickled / 2B (as required) |
| Primary Applications | Pulp & Paper Industry / Wastewater Treatment / Low-Pressure Fluid Transfer / Food Processing / Corn/Ethanol Processing |
| Parameter | Available Options |
|---|---|
| Product Standard | ASTM A778/A778M |
| Grade Equivalents | TP304L (UNS S30403), TP316L (UNS S31603) — plus other austenitic grades listed in Table 1 |
| Outside Diameter (OD) | 3″ through 48″ (75 mm through 1200 mm) |
| Wall Thickness (WT) | 0.062″ through 0.500″ (1.57 mm through 12.70 mm) |
| Length | Single random, double random, or cut-to-length per order |
| Pipe End | Plain End (PE) / Beveled End (BE) — smooth ends free of burrs |
| Welding Process | Straight seam or spiral butt seam by shielded arc-welding (manual or automatic) |
| Heat Treatment | Unannealed (no post-weld heat treatment required) |
| Inspection | Transverse Tension Test / Transverse Guided-Bend Weld Test / Hydrostatic or NDE Test (minimum testing per specification) |
| Documents | MTC 3.1 / Inspection Reports / Packing List / Heat Number Traceability |
ASTM A778 welded unannealed stainless steel pipe is specified for low to moderate temperature corrosive service where post-weld annealing is not required for corrosion resistance. It is considered a commodity product sold primarily through distributors on the basis of price.
Typical applications include:
- Pulp and paper industry process lines
- Wastewater and sewage treatment systems
- Low-pressure fluid transfer systems
- Food and beverage processing (non-critical)
- Corn processing to ethanol production
- Neutralization tank connectors
- Light industry and general corrosive service where cost is a priority
Key selection considerations: ASTM A778 is the cost-effective alternative to ASTM A312 for applications where the heat-affected zone does not require annealing. Because the pipe is supplied unannealed, it is only produced in grades least susceptible to corrosion in the weld-adjacent area. TP304L is suitable for general corrosive service with low chloride concentrations; TP316L is recommended when molybdenum is needed for pitting resistance in chloride-containing environments. The wall thickness range of 0.062″ to 0.500″ (Schedule 5S through Schedule 80 equivalent) covers most industrial applications for low-moderate temperature service. For higher-temperature service, post-weld annealing, or radiographic examination requirements, ASTM A312, A358, or A409 should be specified instead.
Shangyou Stainless Steel provides value-added processing including custom cutting, beveling, and end protection.
All pipes are packed with export-standard protection including protective end caps, steel strapping, waterproof wrapping, and wooden pallets or steel frames.
Quality documents include MTC 3.1, inspection reports, packing list, and heat number traceability. Third-party inspection (SGS, TUV, BV) can be arranged upon request.
ASTM A778 is the standard specification for welded, unannealed austenitic stainless steel tubular products for low and moderate temperature corrosive service where heat treatment is not necessary.
ASTM A312 requires post-weld annealing; ASTM A778 is supplied unannealed. A778 is more cost-effective but limited to applications where the weld heat-affected zone does not require corrosion protection. Both are commodity products and often interchangeable one-way (A312 can replace A778).
Outside diameter 3″ through 48″ (75mm–1200mm) with wall thickness 0.062″ through 0.500″ (1.57mm–12.70mm).
TP304L and TP316L are the most common, plus additional austenitic grades listed in Table 1 of the specification.
No. The key feature of A778 is that it is supplied unannealed—no post-weld heat treatment is required.
Straight seam or spiral butt seam by shielded arc-welding process, manual or automatic.
The specification requires a minimum amount of testing: transverse tension test and transverse guided-bend weld test. Hydrostatic or NDE testing may also apply.
A778 does not require annealing, making it more cost-effective for applications where corrosion in the heat-affected zone is not a concern.
MTC 3.1, inspection reports, packing list, and heat number traceability.
Pulp & paper industry, wastewater treatment, low-pressure fluid transfer, food processing, and ethanol/corn processing.
Need ASTM A778 welded unannealed stainless steel pipe for cost-effective corrosive service in pulp & paper, wastewater, or low-pressure fluid systems? Send requirements including grade (TP304L/TP316L), OD/wall thickness/length, end finish, quantity, and service conditions.
Shangyou Stainless Steel provides custom sizes, processing, and export solutions for global B2B customers.
