SM490B Steel for Welded Structures
SM490B Steel for Welded Structures - JIS G3106 LSAW Pipe Material Analysis
Comprehensive material data for SM490B steel according to JIS G3106, including chemical composition, mechanical properties, and physical performance for longitudinal submerged arc welded (LSAW) pipe applications.
Hot rolling, controlled rolling, normalizing, welding (SAW, LSAW)
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
SM490B Steel for Welded Structures Introduction
SM490B is a hot-rolled steel for welded structures standardized in JIS G3106. It offers a minimum yield strength of 325 MPa (for thickness ≤16 mm) and tensile strength in the range of 490–610 MPa. The material provides good weldability, excellent notch toughness at 0°C (min. 27 J), and is widely used for structural components including LSAW pipes. Its balanced composition ensures reliable performance in bridges, buildings, offshore structures, and pressure vessels. Controlled rolling or normalizing delivery conditions further enhance mechanical homogeneity.
SM490B Steel for Welded Structures Chemical Composition
Chemical requirements according to JIS G3106 for SM490B. Values are for product thickness ≤100 mm. Microalloying elements such as Nb, V, or Ti may be added for grain refinement.
- For thickness ≤50 mm: C ≤0.18%, Mn ≤1.60%
- For thickness >50–100 mm: C ≤0.20%, Mn ≤1.60%
| Element | Standard Value (max, %) | Remarks |
|---|---|---|
| C | 0.18 (≤50 mm); 0.20 (>50–100 mm) | Heat analysis |
| Si | 0.55 | |
| Mn | 1.60 | |
| P | 0.035 | |
| S | 0.035 | |
| Nb, V, Ti | Optional addition | Grain refinement elements |
| CEV (typical) | ≤0.44 | Carbon equivalent, for guidance |
SM490B Steel for Welded Structures Thermal and Electrical Physical Properties
Physical properties are not mandated by JIS G3106 but are representative for SM490B type low-carbon low-alloy steel at ambient temperature (20°C). These values are suitable for engineering calculations.
- Density and elastic moduli are standard for structural steel.
- Thermal expansion and conductivity vary with temperature; values given for 20–100°C range.
| Property | Typical Value | Unit | Remarks / Temperature |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20°C |
| Elastic Modulus (E) | 210 | GPa | 20°C |
| Shear Modulus (G) | 80 | GPa | 20°C |
| Poisson's Ratio (ν) | 0.3 | – | 20°C |
| Thermal Expansion (α) | 12.0 | 10⁻⁶/K | 20–100°C |
| Thermal Conductivity (λ) | 50 | W/(m·K) | 20°C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρₑ) | 0.22 | μΩ·m | 20°C |
SM490B Steel for Welded Structures Mechanical Properties
Transverse tensile properties and Charpy impact requirements as per JIS G3106. Tensile test specimens taken from the product.
- Yield strength varies with thickness.
- Elongation depends on thickness and specimen orientation.
- Charpy V-notch test at 0°C, longitudinal direction, average ≥27 J.
| Property | Standard Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥325 | MPa | Thickness ≤16 mm |
| Yield Strength (ReH) | ≥315 | MPa | 16 < t ≤40 mm |
| Yield Strength (ReH) | ≥295 | MPa | 40 < t ≤75 mm |
| Yield Strength (ReH) | ≥295 | MPa | 75 < t ≤100 mm |
| Tensile Strength (Rm) | 490–610 | MPa | Thickness ≤100 mm |
| Elongation (A) | ≥22 | % | Thickness ≤5 mm, JIS No.5 specimen |
| Elongation (A) | ≥17 | % | 5 < t ≤16 mm, JIS No.1A specimen |
| Elongation (A) | ≥21 | % | 16 < t ≤50 mm, JIS No.1A specimen |
| Elongation (A) | ≥23 | % | >50 mm, JIS No.10 specimen (transverse) |
| Charpy Impact (KV2) | ≥27 (average) | J | 0°C, longitudinal, 10x10 mm specimen |
SM490B Steel for Welded Structures Fully Equivalent Material Standards & Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490B | Base standard |
| EU | EN 10025-2 | S355J0 | Tensile strength 490–630 MPa; 0°C impact |
| USA | ASTM A572/A572M | Grade 50 | ≥345 MPa yield; impact not mandatory |
| China | GB/T 1591 | Q345B | ≥345 MPa yield; 20°C impact, 27J |
| International | ISO 630-2 | S355D | ≥355 MPa yield; -20°C impact, min 47J |
SM490B Steel for Welded Structures Application Introduction
SM490B is designed for welded structures requiring medium strength and good low-temperature toughness. It adapts well to automated welding processes such as LSAW for large-diameter pipes. Typical application industries include:
Product Applications: Longitudinally submerged arc welded (LSAW) pipes, Welded H-beams, box columns, and built-up sections, Heavy plates for shipbuilding and offshore modules, Penstocks and spiral-welded pipes, Crane booms and earthmoving equipment frames
Processed into products: Pipe spools and fittings for high-pressure gas/oil lines, Bridge girder flanges and webs, Wind turbine tower flanges and connecting segments, Structural nodes in steel-frame buildings, Pressure vessel shells and heads (with additional normalizing if required)
Application industries: Civil engineering and construction (bridges, high-rise buildings, stadiums), Offshore and marine engineering (platforms, jackets, ship hulls), Oil & gas transmission (LSAW pipes for onshore and offshore pipelines), Automotive and railway vehicles (chassis, bogie frames), Pressure vessel and boiler manufacturing (up to moderate thickness)
SM490B Steel for Welded Structures Similar / Close Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490YA | Higher yield, controlled Cu-Ni-Cr for weathering |
| Japan | JIS G3106 | SM490C | 0°C impact, same strength, slightly lower CEV in some cases |
| EU | EN 10025-2 | S355JR | Room temp impact, slightly lower toughness requirement |
| EU | EN 10025-3 | S355N | Normalized, fine grain, improved toughness for thicker sections |
| China | GB/T 1591 | Q345C | 0°C impact 34J, comparable strength |
| USA | ASTM A709/A709M | Grade 50 | Bridge steel, similar strength, optional notch toughness |
Notes:
For LSAW pipe production, SM490B plates are typically ordered with supplementary requirements such as ultrasonic testing (UT), through-thickness properties (Z35), or specific carbon equivalent limits. Always confirm the latest edition of JIS G3106 and any project-specific specifications.
- Post-weld heat treatment (PWHT) may affect mechanical properties; consult steel supplier for PWHT simulation data.
- For sour service applications, additional HIC/SSC testing per NACE MR0175 is recommended.
- Share
