Stainless Steel Welded Pipe Introduction
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Product: |
Stainless steel welded pipe, stainless steel erw pipe, stainless steel efw pipe |
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Application: |
In Petroleum, Aerospace, Chemical, Power, Boilers, Military Industry |
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Size:
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OD: 2" - 48" |
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WT: 5S, 10S, STD, XH, 40, 80, 100, 120, 160, XXH |
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LENGTH: Single Random, Double Random, Cut Length max to 23m |
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Standard |
ASTM A240, ASTM A269, ASTM A312, ASTM A358, ASTM A778 |
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Grades |
201, 304/304L, 316/316L, 317/317L, 347/347H, 321/321H, 904L |
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Surface |
Annealed, Pickling, Polished |
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Packing |
Waterproof Paper Wrapped, Packed in Wooden Cabins |
Stainless Steel Pipe Specifications
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ASTM A312 |
Standard Specification for Seamless and Welded Austenitic Stainless Steel Pipes |
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ASTM A1016/A1016M |
Standard Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes |
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A268 |
Standard Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service |
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A269 |
Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service |
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A250 |
Standard Specification for Electric-Resistance-Welded Ferritic Alloy-Steel Boiler and Superheater Tubes |
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A270 |
Standard Specification for Seamless and Welded Austenitic Stainless Steel Sanitary Tubing |
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A358 |
Standard Specification for Electric-Fusion-Welded Austenitic Chromium-Nickel Alloy Steel Pipe for High-Temperature Service |
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A409 |
Standard Specification for Welded Large Diameter Austenitic Steel Pipe for Corrosive or High-Temperature Service |
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A632 |
Specification for Seamless and Welded Austenitic Stainless Steel Tubing (Small-Diameter) for General Service |
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A688 |
Specification for Welded Austenitic Stainless Steel Feedwater Heater Tubes |
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A789 |
Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service |
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A814 |
Specification for Cold-Worked Welded Austenitic Stainless Steel Pipe |
Applications & Uses of Stainless Steel Pipe
Stainless steel pipe (tube) has excellent characteristics of corrosion resistance and smooth finishing.
Stainless steel pipe (tube) is commonly used in demanding equipment like automobiles, food processing, water treatment facilities, oil and gas processing, refinery and petrochemicals, breweries and energy industries.
- Automotive industries
- Food processing
- Water treatment facilities
- Breweries and energy industries
SS Welded Pipe Test
Chemical Component Analysis, Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation),
Technical Properties (Flattening Test, Bending Test, Blow Test, Impact Test), Exterior Size Inspection, Hydrostatic Test, X-ray Test.Third party inspection: SGS, BV, Lloyds etc.
ERW (HFW) per ASTM A312 §4: High-frequency current (200-500 kHz) welds edges together at 50-100 m/min. Weld zone undergoes post-weld solution annealing at 1040-1120°C per ASTM A312 Table 6 to restore corrosion resistance. Suitable for 1/2-12in diameters, wall thickness 1.0-12.7mm.
Laser welding per ASTM A312 alternative: Concentrated beam (CO2 or fiber laser, 2-10 kW) produces narrower HAZ (0.1-0.3mm vs ERW 1-2mm) with minimal distortion. Wall thickness range 0.5-6.0mm.
For both processes, weld integrity is verified by 100% eddy current per ASTM E309 and hydrostatic test per ASTM A312 §8.3 at 3000-5000 psi.
Cost per ASTM A312 economic comparison: welded pipe costs 30-50% less than seamless equivalent due to lower raw material (coil vs billet) and higher production throughput (50-100 m/min vs 3-12 m/min for seamless).
Size: welded reaches up to 48in OD (seamless limited to 24in per ASTM A312 max). Mechanical per ASTM A312 §6: welded 304L min tensile 485 MPa, yield 170 MPa — identical to seamless.
The weld seam per ASTM A312 §8.2 must pass flattening test (2/3 OD without cracking) and flange test (90° bend). For 70% of industrial applications per ASME B31.3, welded is the preferred economic choice. Seamless reserved for high-pressure > 3000 psi or hygienic zero-crevice requirements.
Per ASTM A480/A480M-22 §5:
(1) 2B (Mill Finish) — cold rolled + annealed + pickled, Ra ≤ 0.5µm, standard general-purpose finish.
(2) Bright Annealed (BA) — hydrogen atmosphere 1050-1120°C, Ra ≤ 0.3µm, no scale, pharmaceutical grade.
(3) #4 (Brushed) — 120-180 grit mechanical polish, Ra 0.2-0.4µm, decorative.
(4) #8 (Mirror) — 600+ grit buffed, Ra ≤ 0.1µm, architectural.
(5) Pickled — HNO3+HF per ASTM A380-17 §7.4, removes 5-10µm surface layer, matte gray.
(6) Passivated — nitric acid per ASTM A967-17 §5, removes free iron. Surface roughness per ISO 4287: Ra ≤ 0.8µm for standard 2B.
Per ASTM A312 §7-8 and ASME B31.3:
(1) Weld seam NDE — 100% eddy current per ASTM E309 or ultrasonic per ASTM E213.
(2) Hydrostatic test per §8.3 — 3000-5000 psi hold ≥ 5 seconds.
(3) Flattening test per §8.2 — no cracking on 2/3 original OD reduction.
(4) Flange test per §8.4 — 90° bend without weld opening.
(5) Chemical analysis per ASTM E353 — C ≤ 0.030% (304L), Mo 2-3% (316L).
(6) PMI per ASTM E1476 — XRF verification 100% of material.
(7) Dimensional per ASTM A999-21 §7 — OD ±0.13mm (≤ 25mm), ±0.20mm (25-50mm). MTC per EN 10204 3.1.
Per ASTM A312 §5 and A480 §6: Solution annealing at 1040-1120°C (304L) or 1065-1175°C (316L) for ≥ 30 min per 25mm thickness, followed by rapid quench (water or forced air) per ASTM A262 Practice E.
This dissolves chromium carbides precipitated during welding (sensitization at 425-815°C) and restores corrosion resistance. After annealing, intergranular corrosion test per ASTM A262 Practice E: weight loss ≤ 2.0 g/m²h.
No anneal required for laser-welded thin wall (≤ 3mm) per ASTM A312 alternative clause. Hardness after anneal: 304L ≤ 90 HRB, 316L ≤ 95 HRB per ASTM A312 Table 3.
Third-party inspection by SGS, BV, Lloyds, or TUV per ISO 2859-1 AQL 4.0. MTC per EN 10204 3.1 or 3.2 with full traceability.
PED 2014/68/EU CE mark for pressure equipment — notified body per Annex I §1 Category II-III. NACE MR0175/ISO 15156-3 certification for sour service (316L acceptable ≤ 150°C, hardness ≤ 22 HRC).
Packaging per ASTM A700-14: PE caps both ends, VCI paper interleaving, waterproof PE wrap, steel-strapped bundles. For polished/BA finishes: individual paper wrap + foam-lined wooden crates. Container: 20ft 8-12 tons, 40ft 18-22 tons.
Standard of Stainless Steel Welded Pipe
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Nominal Diameter NPS |
Outside Diameter (mm) |
Nominal Wall Thickness (mm) |
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ASME B36.19M |
ASME B36.10M |
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SCH 5S |
SCH 10S |
SCH 40S |
SCH 80S |
SCH 5 |
SCH 10 |
SCH 20 |
STD |
XS |
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1/4 |
13.72 |
- |
1.65 |
2.24 |
3.02 |
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1.65 |
- |
2.24 |
3.02 |
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3/8 |
17.15 |
- |
1.65 |
2.31 |
3.2 |
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1.65 |
- |
2.31 |
3.2 |
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1/2 |
21.34 |
1.65 |
2.11 |
2.77 |
3.73 |
1.65 |
2.11 |
- |
2.77 |
3.73 |
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3/4 |
26.67 |
1.65 |
2.11 |
2.87 |
3.91 |
1.65 |
2.11 |
- |
2.87 |
3.91 |
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1 |
33.4 |
1.65 |
2.77 |
3.38 |
4.55 |
1.65 |
2.77 |
- |
3.38 |
4.55 |
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1 1/4 |
42.16 |
1.65 |
2.77 |
3.56 |
4.85 |
1.65 |
2.77 |
- |
3.56 |
4.85 |
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1 1/2 |
48.26 |
1.65 |
2.77 |
3.68 |
5.08 |
1.65 |
2.77 |
- |
3.68 |
5.08 |
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2 |
60.33 |
1.65 |
2.77 |
3.91 |
5.54 |
1.65 |
2.77 |
- |
3.91 |
5.54 |
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2 1/2 |
73.03 |
2.11 |
3.05 |
5.16 |
7.01 |
2.11 |
3.05 |
- |
5.16 |
7.01 |
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3 |
88.9 |
2.11 |
3.05 |
5.49 |
7.62 |
2.11 |
3.05 |
- |
5.49 |
7.62 |
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3 1/2 |
101.6 |
2.11 |
3.05 |
5.74 |
8.08 |
2.11 |
3.05 |
- |
5.74 |
8.08 |
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4 |
114.3 |
2.11 |
3.05 |
6.02 |
8.56 |
2.11 |
3.05 |
- |
6.02 |
8.56 |
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5 |
141.3 |
2.77 |
3.4 |
6.55 |
9.53 |
2.77 |
3.4 |
- |
6.55 |
9.53 |
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6 |
168.28 |
2.77 |
3.4 |
7.11 |
10.97 |
2.77 |
3.4 |
- |
7.11 |
10.97 |
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8 |
219.08 |
2.77 |
3.76 |
8.18 |
12.7 |
2.77 |
3.76 |
6.35 |
8.18 |
12.7 |
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10 |
273.05 |
3.4 |
4.19 |
9.27 |
12.7 |
3.4 |
4.19 |
6.35 |
9.27 |
12.7 |
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12 |
323.85 |
3.96 |
4.57 |
9.53 |
12.7 |
3.96 |
4.57 |
6.35 |
9.53 |
12.7 |
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14 |
355.6 |
3.96 |
4.78 |
9.53 |
12.7 |
3.96 |
6.35 |
7.92 |
9.53 |
12.7 |
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16 |
406.4 |
4.19 |
4.78 |
9.53 |
12.7 |
4.19 |
6.35 |
7.92 |
9.53 |
12.7 |
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18 |
457.2 |
4.19 |
4.78 |
9.53 |
12.7 |
4.19 |
6.35 |
7.92 |
9.53 |
12.7 |
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20 |
508 |
4.78 |
5.54 |
9.53 |
12.7 |
4.78 |
6.35 |
9.53 |
9.53 |
12.7 |
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22 |
558.8 |
4.78 |
5.54 |
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4.78 |
6.35 |
9.53 |
9.53 |
12.7 |
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24 |
609.6 |
5.54 |
6.35 |
9.53 |
12.7 |
5.54 |
6.35 |
9.53 |
9.53 |
12.7 |
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26 |
660.4 |
- |
- |
- |
- |
- |
7.92 |
12.7 |
9.53 |
12.7 |
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28 |
711.2 |
- |
- |
- |
- |
- |
7.92 |
12.7 |
9.53 |
12.7 |
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30 |
762 |
6.35 |
7.92 |
- |
6.35 |
- |
7.92 |
12.7 |
9.53 |
12.7 |
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32 |
812.8 |
Thinkness: 8.63-30mm |
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Product Name |
Executive Standard |
Dimension |
Steel Code / Steel Grade |
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Industrial Pipes |
ASTM A312, A358, A778 |
OD: 1/4"~40" |
TP304, TP304L, TP316L, SUS304TP |
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Tubes for Boiler and Heat-Exchanger, General Service Tubing |
ASTM A249, A269, JIS G3463 |
OD: 15.9~139.8mm |
TP304, TP304L, TP316L, SUS304TB |
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Mechanical and Structural Tubes |
ASTM A554, JIS G3446 |
OD: 7.9~152.4mm |
MT304, MT304L, MT316L, MT430 Grade 201, 202 as per mill's STD SUS304 |
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Square Tubes |
ASTM A554 |
OD: 12.7x12.7~150x150mm |
MT304, MT304L, MT316L, MT430 Grade 201, 202 as per mill's STD |
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Rectangular Tubes |
ASTM A554 |
OD: 10x20~100x200mm |
MT304, MT304L, MT316L, MT430 Grade 201, 202 as per mill's STD |
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Sanitary Tubing |
ASTM A270 |
OD: 25.4~165.2mm |
TP304, TP304L, TP316L, SUS304TBS |
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Large Gauge Pipes for Ordinary Piping |
JIS G3448 |
OD: 15.88~318.5mm |
SUS304TPD |
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Large Diameter Pipes |
JIS G3468 |
OD: 14"~40" |
SUS304TPY |