SS Pipes & Fittings
Stainless Steel (SS) ERW Pipe
Stainless Steel (SS) ERW Pipes are produced by cold-forming stainless steel strips into a cylindrical shape and welding the longitudinal seam using high-frequency electric resistance. Unlike seamless pipes, which are extruded from solid billets, ERW pipes are cost-effective and highly accurate in wall thickness, making them ideal for water lines, structural supports, and food processing.
1. Primary Manufacturing Standards
The technical specifications for SS ERW pipes are primarily governed by international ASTM standards:
ASTM A312: The standard for welded austenitic stainless steel pipes used for high-temperature and general corrosive service.
ASTM A249: Specifically for welded austenitic steel boiler, superheater, heat exchanger, and condenser tubes.
ASTM A554: Used for ornamental or structural applications where appearance and mechanical properties are more important than pressure ratings.
2. Technical Parameter Overview
Feature | Technical Specification |
|---|---|
Common Grades | TP304, TP304L, TP316, TP316L, TP321, TP310S |
Size Range (NB) | 1/8” NB to 36” NB |
Outer Diameter (OD) | 6.35 mm to 114.3 mm (for smaller range); up to 24" OD for standard ERW |
Wall Thickness | 0.5 mm to 12.7 mm (Schedules 5S, 10S, 40S, 80S) |
Length | Up to 12 Meters (Single or Double Random Length) |
Surface Finish | 2B (Mill finish), No.4 (Brushed), BA (Bright Annealed), 8K (Mirror) |
3. Material Properties (Grade 304 vs. 316)
These are the two most common grades you will likely deal with:
Property | SS 304 ERW (18/8) | SS 316 ERW (Chloride Resistant) |
|---|---|---|
Chemical Composition | 18% Cr, 8% Ni | 16% Cr, 10% Ni, 2% Mo |
Tensile Strength | 515 MPa (Min) | 515 MPa (Min) |
Yield Strength | 205 MPa (Min) | 205 MPa (Min) |
Max Temp Service | 870°C | 870°C |
Best Used For | Dairy, food, household, architecture | Marine, chemical, pharmaceutical |
4. Dimensional Chart (Standard Schedules)
For SS pipes, the schedules (thicknesses) are often denoted with an "S" (e.g., 40S).
Nominal Size (NB) | OD (mm) | Sch 10S (mm) | Sch 40S (mm) | Weight (kg/m - 40S) |
|---|---|---|---|---|
1/2" (15mm) | 21.34 | 2.11 | 2.77 | 1.29 |
1" (25mm) | 33.40 | 2.77 | 3.38 | 2.54 |
2" (50mm) | 60.33 | 2.77 | 3.91 | 5.52 |
4" (100mm) | 114.30 | 3.05 | 6.02 | 16.32 |