JIS G3106 SM490A LSAW Pipe
SM490A Steel for LSAW Pipe | JIS G3106 Material Properties & Equivalents
Detailed material data for SM490A steel according to JIS G3106, commonly used for LSAW pipes. Includes chemical composition, mechanical and thermal properties, international equivalent grades, and application guidance.
Hot rolling, cold forming, welding, machining, normalized rolling or TMCP as optional
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JIS G3106 SM490A LSAW Pipe Introduction
SM490A is a hot-rolled steel for welded structures specified in JIS G3106. It is a low-carbon, high-strength structural steel with minimum yield strength of 325 MPa for thicknesses up to 16 mm.
- Excellent weldability and formability
- Suitable for LSAW pipes, bridges, buildings, and general welded structures
- Typically supplied in as-rolled or normalized rolling condition
- Not normally intended for impact-sensitive applications unless specifically ordered as SM490B or SM490C
JIS G3106 SM490A LSAW Pipe Chemical Composition
The typical ladle analysis limits for SM490A according to JIS G3106:2015. The steel is non-alloy or low-alloy with controlled carbon and manganese to ensure good weldability. Phosphorus and sulfur are restricted to improve cleanliness and toughness.
| Element | Standard Value (max, %) | Remarks |
|---|---|---|
| Carbon (C) | 0.20 | Ladle analysis |
| Silicon (Si) | 0.55 | May be lower for improved surface quality |
| Manganese (Mn) | 1.65 | Depending on thickness, typical 1.0-1.5 |
| Phosphorus (P) | 0.035 | Strict limit for welded structures |
| Sulfur (S) | 0.035 | Low sulfur for through-thickness properties |
JIS G3106 SM490A LSAW Pipe Thermal and Electrical Physical Properties
Physical properties are typical for low-carbon structural steel and are not part of the JIS standard. They are provided for design reference. Values may vary slightly depending on processing history.
| Property | Typical Value | Unit | Test Condition / Temperature |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of elasticity (E) | 210 | GPa | 20 °C, static |
| Shear modulus (G) | 80 | GPa | 20 °C, calculated |
| Poisson's ratio (ν) | 0.3 | - | 20 °C |
| Thermal expansion (α) | 11.5 | 10⁻⁶/K | 20 - 100 °C |
| Thermal expansion (α) | 12.5 | 10⁻⁶/K | 20 - 200 °C |
| Thermal expansion (α) | 13.5 | 10⁻⁶/K | 20 - 400 °C |
| Thermal conductivity (λ) | 52 | W/(m·K) | 20 °C |
| Thermal conductivity (λ) | 48 | W/(m·K) | 100 °C |
| Thermal conductivity (λ) | 43 | W/(m·K) | 200 °C |
| Specific heat capacity (cp) | 460 | J/(kg·K) | 20 °C |
| Specific heat capacity (cp) | 500 | J/(kg·K) | 200 °C |
| Electrical resistivity (ρe) | 0.16 | μΩ·m | 20 °C |
JIS G3106 SM490A LSAW Pipe Mechanical Properties
Tensile and yield properties are thickness-dependent according to JIS G3106. Elongation values are measured using standard test pieces (No.5 for thin sheet, No.1A for plate, No.4 for heavier sections). Bending test is mandatory with specified bend diameter.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 325 | MPa | Thickness ≤ 5 mm, transverse |
| Yield Strength (ReH) | ≥ 325 | MPa | 5 mm < thickness ≤ 16 mm |
| Yield Strength (ReH) | ≥ 315 | MPa | 16 mm < thickness ≤ 40 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | 40 mm < thickness ≤ 75 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | 75 mm < thickness ≤ 100 mm |
| Yield Strength (ReH) | ≥ 285 | MPa | 100 mm < thickness ≤ 160 mm |
| Tensile Strength (Rm) | 490 - 610 | MPa | All thicknesses |
| Elongation (A) | ≥ 22 | % | Thickness ≤ 5 mm, JIS No.5 specimen |
| Elongation (A) | ≥ 17 | % | 5 mm < t ≤ 16 mm, JIS No.1A specimen |
| Elongation (A) | ≥ 21 | % | 16 mm < t ≤ 50 mm, JIS No.1A specimen |
| Elongation (A) | ≥ 23 | % | t > 40 mm, JIS No.4 specimen |
| Bending Test | 180° bend, no cracks | - | Thickness ≤ 16 mm: bend diameter 1.5t |
| Bending Test | 180° bend, no cracks | - | 16 mm < t ≤ 50 mm: bend diameter 2.0t |
| Bending Test | 180° bend, no cracks | - | 50 mm < t ≤ 100 mm: bend diameter 2.5t |
JIS G3106 SM490A LSAW Pipe Completely Equivalent Material Standards and Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490A | Base standard, as-rolled welded structural steel |
| USA | ASTM A572/A572M | Grade 50 [345] | Similar yield strength, slightly different chemistry, for structural shapes and plates |
| European Union | EN 10025-2 | S355JR | Widely used equivalent, typical yield 355 MPa, suitable for welded structures |
| International | ISO 630-2 | S355JR | Harmonized with EN, for structural purposes |
| China | GB/T 1591 | Q355B | Chinese structural steel, comparable strength, may require impact testing at 20°C |
JIS G3106 SM490A LSAW Pipe Application Introduction
SM490A is primarily used in welded fabrication where a combination of moderate strength and excellent weldability is required. The steel is often formed into LSAW (Longitudinal Submerged Arc Welded) pipes for transporting oil, gas, and water. It is also extensively applied in:
- Structural frameworks of buildings and industrial plants
- Bridge components and girders
- Offshore platform topsides
- Pressure vessel shells and heads
- Heavy machinery and vehicle chassis
Product Applications: Longitudinal SAW pipes and spiral welded pipes, Heavy steel plates for welded junctions, Built-up beams and columns, Pressure vessels and storage tanks, Piling pipes and foundation casings
Processed into products: Pipe lengths and fittings for oil and gas trunk lines, Flanges, tees, elbows, and reducers for piping systems, Gusset plates, base plates, and stiffeners in steel frames, Welded box sections and I-girders for bridge decks, Crane booms and hydraulic cylinder bodies
Application industries: Oil & Gas (pipeline, transmission), Construction (high-rise, bridges, stadiums), Shipbuilding and Marine (deck plates, stiffeners), Power Generation (penstocks, structural supports), Mining and Earthmoving (dump bodies, booms), Industrial Machinery (frames, cylinders)
JIS G3106 SM490A LSAW Pipe Similar / Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490B | Higher toughness requirement (impact at 0°C), otherwise similar chemical and strength |
| Japan | JIS G3106 | SM490C | Highest toughness (impact at -10°C), used for critical welded structures |
| USA | ASTM A572/A572M | Grade 42 [290] | Lower yield strength alternative if less strength is acceptable |
| European Union | EN 10025-2 | S275JR | Lower strength alternative, widely available, may be used for less demanding LSAW pipe |
| China | GB/T 1591 | Q345B | Slightly lower strength than Q355B, historically equivalent to SM490A, still common |
Notes:
SM490A does not normally require impact testing. For LSAW pipe applications, supplementary requirements such as through-thickness tensile testing, ultrasonic testing, or drop weight tear test may be specified. The pipe forming process (UOE or JCO) can alter mechanical properties; the values given refer to the base plate per JIS G3106. For pipe body mechanical testing, refer to the specific pipe standard (e.g., API 5L, ISO 3183).
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