MS Pipes & Fittings
Mild Steel (MS) ERW Pipe
MS ERW Pipes (Mild Steel Electric Resistance Welded) are the backbone of many industrial, structural, and utility projects. While "MS" tells you the material (low carbon steel), "ERW" describes how it's made: by cold-forming a steel strip into a cylinder and fusing the longitudinal seam using high-frequency electric current without any filler material.
Technical Specifications (IS 1239 / IS 3589)
In India, these pipes are typically governed by two major standards: IS 1239 (for sizes up to 6" NB) and IS 3589 (for larger diameters).
1. General Parameters
Features | Description | Manual sort |
|---|---|---|
Material Grade | Fe 330, Fe 410, Fe 450 (Mild Steel) | 8 |
Standard | IS 1239 (Part 1), IS 3589, ASTM A53 | 9g |
Size Range | 15mm (1/2") to 508mm (20") NB and above | a |
Length | Single Random (4–7m) or Double Random (up to 12m) | c |
Surface Finish | Black (Natural), Varnished, or Hot-Dip Galvanized (GI) | g |
2. Chemical Composition & Mechanical Properties
Property | Requirement (Typical for Fe 410) | Manual sort |
|---|---|---|
Carbon (C) | 0.20% max | 8 |
Manganese (Mn) | 1.30% max | 9 |
Phosphorus (P) / Sulphur (S) | 0.040% max each | 9g |
Tensile Strength | 320 MPa to 410 MPa (min) | a |
Yield Strength | 235 MPa (min) | c |
Elongation | 18% to 20% (min) | g |
3. Standard Dimensions & Weights (IS 1239)
Commonly referred to by "Class" (Light, Medium, Heavy), which determines the wall thickness.
Nominal Bore (NB) | Outside Dia (mm) | Light (Class A) - mm / kg/m | Medium (Class B) - mm / kg/m | Heavy (Class C) - mm / kg/m |
|---|---|---|---|---|
1/2" (15mm) | 21.43 | 2.00 / 0.95 | 2.65 / 1.22 | 3.25 / 1.45 |
1" (25mm) | 33.80 | 2.60 / 2.00 | 3.25 / 2.44 | 4.05 / 2.97 |
2" (50mm) | 60.30 | 2.90 / 4.11 | 3.65 / 5.10 | 4.47 / 6.17 |
3" (80mm) | 88.90 | 3.25 / 6.81 | 4.05 / 8.47 | 4.85 / 10.10 |
4" (100mm) | 114.30 | 3.65 / 9.89 | 4.50 / 12.60 | 5.40 / 14.40 |
Manufacturing Tests (Quality Assurance)
To ensure the weld is as strong as the parent metal, ERW pipes undergo several mandatory tests:
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Hydrostatic Test: The pipe is filled with water at high pressure (usually 5 MPa) to check for leaks.
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Flattening Test: A sample is flattened between two plates; the weld seam must not crack or open.
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Bend Test: Used for smaller diameters to ensure ductility.
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Eddy Current/Ultrasonic Test: Non-destructive testing (NDT) to find internal flaws in the weld.
Key Advantages of ERW
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Dimensional Accuracy: Highly consistent wall thickness and diameter compared to seamless pipes.
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Smooth Surface: Better for painting or coating (like the epoxy or 3LPE coatings used in industrial gas lines).
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Cost-Effective: Faster and more efficient production makes them cheaper for structural and water applications.