JIS G3106 SM490C Steel for SSAW Pipe
JIS G3106 SM490C Steel for SSAW Pipe - Weldable Structural Grade
Detailed material data for JIS G3106 SM490C steel used in spiral submerged arc welded (SSAW) pipes, covering chemical composition, mechanical and physical properties, international equivalents, and applications.
Welding (especially SSAW), cutting, bending, machining, and cold forming
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JIS G3106 SM490C Steel for SSAW Pipe Introduction
SM490C is a weldable structural steel grade specified in JIS G3106, primarily supplied as hot-rolled plates, sheets, and strips. It is designed for welded structures such as bridges, ships, and construction machinery. When formed into SSAW (Spiral Submerged Arc Welded) pipes, SM490C provides excellent strength and toughness, making it suitable for high-pressure fluid transport, piling, and structural columns.
The steel offers a minimum yield strength of 325 MPa (for thickness ≤16 mm) and tensile strength between 490 and 610 MPa. It guarantees impact energy of at least 47 J at 0°C, ensuring reliable performance in moderate-temperature environments. With good weldability and formability, SM490C is a cost-effective solution for large-diameter, thick-wall welded pipes.
JIS G3106 SM490C Steel for SSAW Pipe Chemical Composition
The chemical composition conforms to JIS G3106. SM490C is a low-carbon steel with controlled additions of manganese and silicon to achieve required strength and weldability. Phosphorus and sulfur are kept low to ensure toughness and cleanliness.
Optional microalloying elements (e.g., Nb, V, Ti) may be added at the manufacturer's discretion to refine grain size and improve mechanical properties.
| Element | Standard Value | Remarks |
|---|---|---|
| C (Carbon) | ≤ 0.18 | Heat analysis |
| Si (Silicon) | ≤ 0.55 | Heat analysis |
| Mn (Manganese) | ≤ 1.65 | Heat analysis |
| P (Phosphorus) | ≤ 0.035 | Heat analysis |
| S (Sulfur) | ≤ 0.035 | Heat analysis |
| Other elements | May include Nb, V, Ti (optional) | For grain refinement and strength |
JIS G3106 SM490C Steel for SSAW Pipe Thermal & Electrical Physical Properties
The following physical properties are typical for carbon structural steels and can be used for design calculations. These values are not mandated by JIS G3106 but are representative for SM490C material.
Actual values may vary slightly depending on exact composition and processing.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20°C |
| Modulus of Elasticity (E) | 206 | GPa | At 20°C |
| Shear Modulus (G) | 80 | GPa | Calculated |
| Poisson's Ratio (ν) | 0.3 | — | At 20°C |
| Thermal Expansion Coefficient (α) | 11.7 (10⁻⁶/K) | K⁻¹ | Range 20–100°C |
| Thermal Conductivity (λ) | 53 | W/(m·K) | At 20°C |
| Specific Heat Capacity | 460 | J/(kg·K) | At 20°C |
| Electrical Resistivity (ρ_e) | 0.16 | μΩ·m | At 20°C |
JIS G3106 SM490C Steel for SSAW Pipe Mechanical Properties
Mechanical properties depend on the thickness of the hot-rolled base material. The values below apply to the steel before pipe forming; however, SSAW pipe mechanical requirements follow the same standard unless otherwise specified.
Testing is performed on standard specimens: tensile test (JIS Z 2241) with gauge length 50 mm or 200 mm depending on thickness, Charpy impact test (JIS Z 2242) at 0°C, and bend test (JIS Z 2248) with 180° bending.
All values are minimum unless a range is given.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 325 | MPa | Thickness ≤ 16 mm |
| Yield Strength (ReH) | ≥ 315 | MPa | Thickness 16–40 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | Thickness 40–75 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | Thickness 75–100 mm |
| Tensile Strength (Rm) | 490–610 | MPa | All thicknesses |
| Elongation (A) | ≥ 17 | % | Thickness ≤ 16 mm, gauge length 50 mm |
| Elongation (A) | ≥ 21 | % | Thickness 16–40 mm, gauge length 200 mm (No. 5 test piece) |
| Elongation (A) | ≥ 23 | % | Thickness > 40 mm, gauge length 200 mm (No. 5 test piece) |
| Bend Test | 180° bend, no cracks | — | Inside radius = 1.0×thickness (t ≤ 25 mm); 1.5×thickness (t > 25 mm) |
| Charpy Impact (KV₂) | ≥ 47 (longitudinal) | J | At 0°C, V-notch (JIS No. 4 test piece) |
JIS G3106 SM490C Steel for SSAW Pipe Exact Equivalent Standards & Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-2 | S355J0 | Comparable tensile/yield strength, 0°C impact (27 J min vs. 47 J for SM490C). Slightly lower toughness guarantee. |
| China | GB/T 1591 | Q355C | Similar yield and tensile strength, 0°C impact 34 J minimum; check thickness ranges. |
| USA | ASTM A572/A572M | Grade 50 [345] | Yield 345 MPa (50 ksi), tensile 450 MPa; impact properties optional; not directly equivalent without supplementary requirements. |
| International | ISO 630-2 | S355J0 | Closely aligned with EN 10025-2, offers 0°C impact energy 27 J. |
JIS G3106 SM490C Steel for SSAW Pipe Application Introduction
SM490C SSAW pipe, fabricated from JIS G3106 hot-rolled coils, is ideal for large-diameter, high-pressure fluid transportation and structural applications. Its combination of strength, weldability, and adequate toughness at 0°C makes it a workhorse for infrastructure projects.
Key advantages:
- Cost-effective spiral welding process for long-distance pipelines
- Good base material formability allows pipe diameters up to 3000 mm
- Proven performance in seismic and moderate-temperature environments
Product Applications: Spiral submerged arc welded (SSAW) pipes, Long-distance cross-country pipelines, Structural columns and piles, Water main distribution pipes, Penstocks for hydropower plants, Offshore platform legs and braces
Processed into products: Pipe sections for oil and gas trunklines, Caissons and jacket legs for offshore platforms, Bridge arch ribs and towers, Steel pipe piles for deep foundations, Wind turbine tower sections (if diameter/thickness permits), Dredging and slurry transport pipes
Application industries: Oil & Gas Transmission, Water Supply and Sewage, Civil Engineering and Construction, Marine and Offshore Structures, Bridge Building, Piling and Foundation Works
JIS G3106 SM490C Steel for SSAW Pipe Similar or Alternative Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490A / SM490B | Lower toughness (A: no impact; B: 0°C but lower energy). SM490C is preferred for demanding applications. |
| Japan | JIS G3101 | SS490 | General structural steel, no specified impact properties; not recommended for dynamic loads. |
| Europe | EN 10025-2 | S355J2 | Higher toughness grade (−20°C, 27 J); excellent alternative if better low-temperature performance is needed. |
| USA | ASTM A709/A709M | Grade 50 | Structural steel for bridges; similar strength but impact testing is optional. |
| China | GB/T 1591 | Q355D | Low-temperature impact (−20°C) for demanding structural applications. |
Notes:
For SSAW pipes, the final pipe properties may be influenced by the welding procedure and post-weld heat treatment. Users should reference API 5L or other pipe-specific standards for finished product requirements. SM490C is not designed for elevated temperature service above 400°C.
The information provided is based on the latest edition of JIS G3106:2015. Always verify with the actual material certificate.
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