JIS G3106 SM490YB LSAW Pipe Steel
JIS G3106 SM490YB LSAW Pipe Steel - Comprehensive Material Data
Full technical details of SM490YB steel grade for LSAW pipes according to JIS G3106: chemical composition, mechanical and thermal properties, international equivalents, and application guide.
Welding (LSAW, ERW), hot rolling, cold forming, bending, machining
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JIS G3106 SM490YB LSAW Pipe Steel Introduction
SM490YB is a high-strength weldable structural steel specified in JIS G3106, widely used for LSAW (Longitudinal Submerged Arc Welded) pipes in heavy steel structures. It offers a minimum yield strength of 365 MPa and guaranteed impact toughness at 0 °C (Charpy V-notch 27 J). The grade belongs to the SM490Y family with enhanced mechanical properties compared to standard SM490.
- Automatically used for welded pipes, pressure vessels, bridges, and offshore structures
- Excellent weldability and formability with controlled carbon equivalent
- Available in plates and coils for pipe forming and other structural applications
JIS G3106 SM490YB LSAW Pipe Steel Chemical Composition
The chemical composition of SM490YB is defined in JIS G3106. Maximum limits are given for main elements. Microalloying elements such as Nb, V, Ti may be added to meet strength requirements, but are not specified by the standard. Typical carbon equivalent (CEV) is controlled for weldability. The values below are the standard heat analysis limits.
| Element | Standard Value (max %) | Remarks |
|---|---|---|
| Carbon (C) | 0.20 | Maximum allowed |
| Silicon (Si) | 0.55 | Maximum allowed |
| Manganese (Mn) | 1.65 | Maximum allowed; may be adjusted upward to meet mechanical properties |
| Phosphorus (P) | 0.035 | Maximum |
| Sulfur (S) | 0.035 | Maximum |
| Copper (Cu) | ≤ 0.40 (residual) | Not specified; residual level under normal practice |
| Nickel (Ni) | ≤ 0.40 (residual) | Residual element, not required by standard |
| Chromium (Cr) | ≤ 0.30 (residual) | Residual element |
| Molybdenum (Mo) | ≤ 0.10 (residual) | Residual element |
| Niobium (Nb) | ≤ 0.05 (optional) | Microalloying element to improve strength and toughness; not mandated |
| Vanadium (V) | ≤ 0.10 (optional) | Microalloying; may be added |
| Titanium (Ti) | ≤ 0.05 (optional) | Microalloying; grain refinement |
| Nitrogen (N) | ≤ 0.012 (residual) | Not specified but controlled in steelmaking |
JIS G3106 SM490YB LSAW Pipe Steel Thermal & Electrical Physical Properties
Physical properties for SM490YB are representative of carbon-manganese structural steels. Exact values may vary slightly with heat treatment and composition. These data serve as engineering reference for thermal and electrical calculations. Properties are measured at room temperature unless stated otherwise.
| Property | Typical Value | Unit | Conditions / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Modulus of Elasticity (E) | 205 | GPa | 20 °C, static test |
| Shear Modulus (G) | 80 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.30 | - | Typical for steel |
| Coefficient of Thermal Expansion (α) | 11.5 × 10⁻⁶ | K⁻¹ | Between 20 °C and 100 °C |
| Thermal Conductivity (λ) | 51 | W/(m·K) | At 25 °C |
| Specific Heat Capacity (cp) | 486 | J/(kg·K) | At 20 °C |
| Electrical Resistivity (ρₑ) | 0.15 – 0.20 | µΩ·m | At 20 °C |
JIS G3106 SM490YB LSAW Pipe Steel Mechanical Properties
Mechanical properties of SM490YB are determined on test pieces taken from plates (or pipe base material) according to JIS G3106. Values vary with thickness. Minimum yield and tensile strength, elongation, bend test, and Charpy impact toughness are specified. All values meet JIS G3106 requirements. The data below covers the most common thickness range for LSAW pipe manufacture.
| Property | Standard Requirement / Typical Value | Unit | Test Condition / Thickness |
|---|---|---|---|
| Yield Strength (ReH, min) | ≥ 365 | MPa | t ≤ 16 mm |
| Yield Strength (ReH, min) | ≥ 355 | MPa | 16 < t ≤ 40 mm |
| Yield Strength (ReH, min) | ≥ 335 | MPa | 40 < t ≤ 75 mm |
| Yield Strength (ReH, min) | ≥ 325 | MPa | 75 < t ≤ 100 mm |
| Tensile Strength (Rm) | 490 – 610 | MPa | All thicknesses |
| Elongation (A, min) | ≥ 17 | % | 5 < t ≤ 16 mm, JIS test piece No.5 (GL=50 mm) |
| Elongation (A, min) | ≥ 21 | % | 16 < t ≤ 50 mm, JIS test piece No.1A (GL=200 mm) |
| Elongation (A, min) | ≥ 23 | % | t > 50 mm, JIS test piece No.4 (GL=50 mm) |
| Bend Test (Bend Angle: 180°) | Bend Diameter = 1.0 × t | - | t ≤ 16 mm |
| Bend Test | Bend Diameter = 1.5 × t | - | 16 < t ≤ 100 mm |
| Charpy V‑Notch Impact Test (KV₂, min) | ≥ 27 | J | Test temperature: 0 °C, longitudinal specimen |
JIS G3106 SM490YB LSAW Pipe Steel Fully Equivalent International Material Standards & Grades
| Country / Region | Standard | Designation | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490YB | Original grade; high yield strength with 0°C impact requirement |
| Europe | EN 10025-2 | S355J2 (+N or +M) | Close match; min YS 355 MPa, impact at -20°C; SM490YB often used where S355J2 is specified for welded pipes |
| China | GB/T 1591 | Q355D | Equivalent yield class; requires lower impact temperature (-20°C). For 0°C toughness, Q355C may be considered |
| United States | ASTM A572 / A572M | Grade 50 (Type 1) | YS 345 MPa, similar strength range; however SM490YB has higher specified minimum yield. Acceptable alternative after engineering evaluation |
| International | ISO 4950 / ISO 4951 | E355D | Similar mechanical requirements; used for structural hollow sections and tubes |
JIS G3106 SM490YB LSAW Pipe Steel Application Introduction
SM490YB steel plates and coils are primarily rolled for manufacturing longitudinally welded (LSAW) pipes used in demanding structural and pipeline applications. The combination of high yield strength, good notch toughness at 0 °C, and excellent weldability makes it suitable for:
Product Applications: Large‑diameter LSAW pipes (up to 60 inches and above), Structural hollow sections (square/rectangular tubes), Welded beams, columns, and built‑up sections, Pipe spools and fittings for high‑pressure service, Offshore conductor pipes and piles
Processed into products: Longitudinal seam welded pipe bodies, Tubular truss members and chord members, Pipeline riser sections, Piling pipes with welded longitudinal seams, Pressure vessel shells and end caps, Ship hull stiffeners and deck plates (when supplied as plate)
Application industries: Oil & gas transmission (LSAW line pipe), Offshore engineering (jackets, risers, caissons), Infrastructure and bridge construction, Shipbuilding and marine structures, Pressure vessels and storage tanks, Industrial machinery and heavy equipment, Piling and foundation engineering
JIS G3106 SM490YB LSAW Pipe Steel Similar / Alternative Material Grades
| Country / Region | Standard | Designation | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490YA | Higher yield strength (≥365 MPa) but no impact requirement; suitable for non‑cryogenic applications |
| Japan | JIS G3106 | SM490B | Standard strength (YS ≥325 MPa) with 0°C toughness; used where lower strength is acceptable |
| Europe | EN 10025-2 | S355MC / S420M (thermomechanical) | Thermomechanically rolled grades with similar or higher yield, often used for cold‑formed pipes |
| United States | ASTM A572 | Grade 55 | YS 380 MPa, closer to SM490YB strength; impact test not mandatory unless supplementary requirement is ordered |
| South Korea | KS D 3515 | SM 490 YB | Korean standard identical to JIS SM490YB, fully interchangeable |
Notes:
Additional Remarks:
- SM490YB plates for LSAW pipe are usually supplied with carbon equivalent (CE) ≤ 0.40% to ensure good weldability. Standard CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15.
- For sour service or low‑temperature applications, supplementary requirements (e.g., HIC testing, lower impact temperature) may be specified per customer request.
- Dimensional tolerances and ultrasonic testing of plates follow JIS G3193 or customer agreements.
- Heat treatment condition (as‑rolled, normalizing, TMCP) should be clearly defined in the purchase order.
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