316 Stainless Steel Welded Pipe Chloride Corrosion Resistant Molybdenum Containing Austenitic Industrial Pipe
316 stainless steel welded pipe is manufactured by roll-forming stainless steel coil or plate into a tubular shape, followed by longitudinal welding. As a molybdenum-bearing austenitic stainless steel grade, it offers significantly improved resistance to chloride pitting and crevice corrosion compared to 304 stainless steel, while maintaining good high-temperature strength and workability.
316 ss welded pipe is produced from high-quality stainless steel coil using automated welding processes, followed by solution annealing to restore corrosion resistance and eliminate welding residual stresses. The addition of molybdenum (2.0–3.0%) makes this material particularly effective in aggressive corrosive environments, especially those containing chlorides.
316 pipe is manufactured and supplied according to the following standards:
| Standard | Scope |
|---|---|
| ASTM A312 | Austenitic stainless steel welded pipe for pressure, high-temperature, and corrosive service |
| ASTM A358 | Electric-fusion-welded pipe for high-temperature service |
| ASTM A778 | Welded pipe for general corrosive service |
| ASME B36.19 | Stainless steel pipe dimensions |
| EN 10217-7 | Welded stainless steel pipe for pressure purposes (European standard) |
| JIS G3459 | Stainless steel pipe (Japanese standard) |
| GB/T 12771 | Welded stainless steel pipe for fluid handling (Chinese standard) |
Raw Material – Stainless steel coil or plate conforming to ASTM A240, grade 316/316L austenitic stainless steel
Forming & Welding – The steel strip is continuously roll-formed into a tubular shape, and the longitudinal seam is welded using automated methods. Common welding processes include TIG (GTAW), plasma arc welding (PAW), and laser welding. Welding is performed under protective atmosphere to prevent oxidation of the weld metal and ensure weld corrosion resistance.
Post-Weld Treatment – Solution annealing (1040–1120°C) to relieve internal stresses, homogenize the metallurgical structure, and restore maximum corrosion resistance. Inner and outer weld beads are removed to create a smooth inner surface and reduce flow resistance. Surface finishing options include pickling, passivation, and polishing (#4, #6, #8 mirror finish) as required.
Inspection & Testing – Chemical composition analysis, mechanical property testing, hydrostatic testing or non-destructive testing (eddy current / ultrasonic), intergranular corrosion testing, dimensional inspection.
| Classification | Description |
|---|---|
| By application | Fluid handling pipe, chemical piping, marine pipe, heat exchanger tube, sanitary pipe |
| By shape | Round pipe, square pipe, rectangular pipe |
| By surface finish | Pickled, annealed, polished (6K/8K mirror), brushed |
| Parameter | Details |
|---|---|
| Product Name | 316 Stainless Steel Welded Pipe / 316L Stainless Steel Welded Pipe |
| Applicable Standards | ASTM A312, EN 10217-7, JIS G3459, GB/T 12771 |
| Material Grade | 316, 316L (UNS S31600 / S31603) |
| Manufacturing Type | Welded pipe (longitudinally welded) |
| OD Range | 12.0mm – 3000mm (custom available) |
| Wall Thickness Range | 0.5mm – 30.0mm (custom available) |
| Length | 6m fixed length, or cut to size (5.8M, 6M, 11.8M, 12M, etc.) |
| Surface Finish | Pickled, annealed, brushed, polished (6K/8K mirror) |
| End Finish | Plain ends, beveled ends, threaded, grooved |
Common dimensions for 316 stainless steel welded pipe are as follows:
| Nominal Bore DN | OD (mm) | Wall Thickness (mm) Range | Common WT (mm) |
|---|---|---|---|
| DN15 | 21.3 | 0.8-2.5 | 1.5, 2.0 |
| DN20 | 26.7 | 0.8-2.5 | 1.5, 2.0 |
| DN25 | 33.4 | 1.0-3.0 | 1.5, 2.0, 2.5 |
| DN32 | 42.2 | 1.0-3.0 | 1.5, 2.0, 2.5 |
| DN40 | 48.3 | 1.0-3.5 | 1.5, 2.0, 2.5 |
| DN50 | 60.3 | 1.2-4.0 | 1.5, 2.0, 2.5, 3.0 |
| DN65 | 76.1 | 1.5-4.0 | 2.0, 2.5, 3.0 |
| DN80 | 88.9 | 1.5-5.0 | 2.0, 2.5, 3.0, 4.0 |
| DN100 | 101.6 | 1.5-5.0 | 2.0, 2.5, 3.0, 4.0 |
| DN125 | 133.0 | 2.0-6.0 | 2.5, 3.0, 4.0, 5.0 |
| DN150 | 159.0 | 2.0-6.0 | 2.5, 3.0, 4.0, 5.0 |
| DN200 | 219.0 | 2.5-8.0 | 3.0, 4.0, 5.0, 6.0 |
| DN250 | 273.0 | 3.0-10.0 | 4.0, 5.0, 6.0, 8.0 |
| DN300 | 325.0 | 3.0-12.0 | 4.0, 5.0, 6.0, 8.0, 10.0 |
Note: The above are common dimensions. Custom sizes are available upon request. Maximum OD up to 3000mm, maximum wall thickness up to 30mm.
316 stainless steel welded pipe is available in the following Schedule wall thickness grades:
| Schedule | Wall Thickness Characteristic | Typical Applications |
|---|---|---|
| Sch 10S | Thin wall | Low-pressure fluid handling, weight-sensitive projects |
| Sch 40S | Standard wall (most common) | Medium-pressure industrial piping, chemical lines |
| Sch 80S | Thick wall | High-pressure service, buried pipelines |
316 stainless steel welded pipe, with its excellent chloride corrosion resistance and good overall properties, is widely used in the following highly corrosive environments:
| Industry | Typical Applications |
|---|---|
| Marine & Offshore | Seawater piping, ballast systems, offshore platform lines, dock facilities, desalination equipment |
| Chemical & Petrochemical | Chloride-containing media transfer lines, pickling equipment, organic chemical piping, reactor connections |
| Pharmaceutical & Biotech | Purified water systems, WFI (water for injection) piping, clean piping, bioreactors |
| Food & Beverage | Salt-containing food processing lines, soy sauce/vinegar transfer, CIP cleaning systems |
| Pulp & Paper | Bleaching systems, chlorine dioxide lines, digester piping |
| Energy & Environmental | Flue gas desulfurization (FGD) units, nuclear auxiliary systems, wastewater treatment equipment |
| Semiconductor & Electronics | High-purity chemical transfer, ultra-pure water systems, process gas lines |
| Construction & Decoration | Coastal building water supply systems, swimming pool piping, high-end decorative structural components |
| Comparison | 304 Stainless Steel | 316 Stainless Steel |
|---|---|---|
| Molybdenum (Mo) content | None | 2.0–3.0% |
| Chloride pitting resistance | Moderate | Excellent |
| Crevice corrosion resistance | Moderate | Excellent |
| Seawater corrosion resistance | Not recommended | Recommended |
| High-temperature strength | Good | Better |
| Cost | Lower | Higher (approx. +30–40%) |
| Suitable environments | General industry, food, potable water | Marine, chemical, pharmaceutical – highly corrosive environments |
| Environment | Recommended Grade | Reason |
|---|---|---|
| General industry, atmospheric exposure, fresh water | 304 | Cost-effective, meets basic corrosion requirements |
| Coastal areas, salt-containing environments | 316 | Molybdenum provides additional chloride protection |
| Direct seawater contact (piping, heat exchangers) | 316 / 316L | Molybdenum-bearing austenitic stainless steel required |
| Chemical chloride-containing media | 316L | Low carbon + molybdenum – optimal corrosion resistance |
| Pharmaceutical, bioengineering | 316L | High cleanliness, excellent corrosion resistance |
| Welded applications requiring maximum corrosion resistance | 316L | Low carbon prevents welding sensitization |
| Comparison | 316 | 316L |
|---|---|---|
| Carbon content | ≤0.08% | ≤0.03% (lower) |
| Intergranular corrosion resistance | Moderate | Excellent (more stable after welding) |
| Strength | Slightly higher | Slightly lower |
| Recommended applications | General corrosive environments, minimal or no welding | Piping systems requiring welding, chloride-containing corrosive environments |
Recommendation: If your piping system requires significant welding or will be exposed to conditions that risk intergranular corrosion, 316L is the preferred choice.
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