JIS G3106 SM570 High-Tensile Steel for Welded Structures
JIS G3106 SM570 High-Tensile Steel for Welded Structures - LSAW Pipe Material
Comprehensive data for SM570 steel according to JIS G3106, including chemical composition, mechanical properties, thermal and electrical characteristics, equivalent grades, and application guide for LSAW pipes and structural components.
Welding (SAW, SMAW, GMAW), hot forming, cold bending, machining, cutting
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JIS G3106 SM570 High-Tensile Steel for Welded Structures Introduction
SM570 is a high-tensile strength steel for welded structures defined in JIS G3106. It offers minimum yield strength of 450 MPa (for thickness ≤ 16 mm) and tensile strength of 570–720 MPa, making it suitable for demanding structural applications. The grade is specifically designed for excellent weldability and toughness, often supplied in as-rolled, normalized, or thermo-mechanically controlled process (TMCP) conditions. When used for LSAW (Longitudinal Submerged Arc Welded) pipes, SM570 plates are formed into cylindrical shapes and longitudinally welded, providing high-strength pipelines for energy and infrastructure projects. Key features:
- High strength with good ductility
- Superior weldability for thick sections
- Impact toughness at 0°C
- Applicable for pressure-containing parts
JIS G3106 SM570 High-Tensile Steel for Welded Structures Chemical Composition
Based on JIS G3106:2015 for SM570, the following elements are controlled. Single values are maximums unless otherwise indicated. Micro-alloying elements such as Nb, V, Ti may be present to achieve strength and toughness, but their individual limits are not specified in the standard except through carbon equivalent. Carbon Equivalent (CE) is typically limited to 0.44% max for thickness ≤ 50 mm to ensure weldability.
| Chemical Element | Standard Value (wt%) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.18 | Max |
| Silicon (Si) | ≤ 0.55 | Max |
| Manganese (Mn) | ≤ 1.60 | Max |
| Phosphorus (P) | ≤ 0.035 | Max |
| Sulfur (S) | ≤ 0.035 | Max |
| Ceq (Carbon equivalent) | ≤ 0.44 | For thickness ≤ 50 mm; formula: Ceq = C + Mn/6 + Si/24 + Ni/40 + Cr/5 + Mo/4 + V/14 |
JIS G3106 SM570 High-Tensile Steel for Welded Structures Thermal, Electrical and Physical Properties
These are typical physical properties for SM570 grade at ambient temperature. Actual values may vary slightly with chemical composition and manufacturing process. Data are provided for general engineering calculations and are not specified in JIS G3106.
| Property | Typical Value | Unit | Test Conditions / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | at 20°C |
| Modulus of Elasticity (E) | 205 | GPa | at 20°C |
| Shear Modulus (G) | 80 | GPa | at 20°C (estimated from E and ν) |
| Poisson's Ratio (ν) | 0.29 | – | at 20°C |
| Thermal Expansion Coefficient (α) | 11.5 × 10⁻⁶ | /°C | 20°C to 100°C |
| Thermal Conductivity (λ) | 52 | W/(m·K) | at 100°C |
| Specific Heat Capacity (c) | 480 | J/(kg·K) | at 20°C |
| Electrical Resistivity (ρₑ) | 0.25 × 10⁻⁶ | Ω·m | at 20°C |
JIS G3106 SM570 High-Tensile Steel for Welded Structures Mechanical Properties
Mechanical properties are verified on test pieces taken from the plate or pipe base material. Yield strength and tensile strength depend on thickness. Elongation is measured on specified gauge length specimens. Impact test is required for thickness ≥ 12 mm unless otherwise agreed, with test temperature at 0°C and minimum absorbed energy of 47 J (longitudinal direction).
| Property | Standard Requirement Value | Unit | Test Conditions |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 450 | MPa | Thickness ≤ 16 mm |
| Yield Strength (ReH) | ≥ 430 | MPa | Thickness 16 < t ≤ 40 mm |
| Yield Strength (ReH) | ≥ 420 | MPa | Thickness 40 < t ≤ 75 mm |
| Yield Strength (ReH) | ≥ 410 | MPa | Thickness 75 < t ≤ 100 mm |
| Tensile Strength (Rm) | 570 – 720 | MPa | All thicknesses |
| Elongation (A) | ≥ 19 | % | Thickness 5-16 mm, test piece No.5 (gauge 50 mm), transverse |
| Elongation (A) | ≥ 26 | % | Thickness >16-50 mm, test piece No.1A (gauge 200 mm), longitudinal |
| Elongation (A) | ≥ 20 | % | Thickness >50 mm, test piece No.4 (gauge 50 mm), longitudinal |
| Charpy Impact (KV2) | ≥ 47 | J | Test at 0°C, longitudinal, specimen size 10×10 mm, thickness ≥ 12 mm |
JIS G3106 SM570 High-Tensile Steel for Welded Structures Equivalent Material Standards and Substitutable Grades
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM570 | Base standard |
| China | GB/T 1591 | Q460D | Similar yield and tensile range; confirm CE and toughness |
| Europe | EN 10025-2 | S460N | Normalized, yield ≥ 460 MPa for t≤16mm, tensile 540-720 MPa; impact -20°C |
| Europe | EN 10025-2 | S460Q | Quenched and tempered, yield ≥ 460/440, tensile 550-720 MPa |
| Europe | EN 10025-4 | S460M | TMCP, yield ≥ 460/440, tensile 530-720 MPa |
| USA | ASTM A572/A572M | Grade 65 [450] | Yield ≥ 450 MPa, tensile ≥ 550 MPa (min lower than SM570); verify strength |
| International | ISO 630-2 | E460 | High-strength structural steel, yield 460 MPa min |
JIS G3106 SM570 High-Tensile Steel for Welded Structures Application Introduction
SM570 steel is extensively used in welded structures requiring high strength-to-weight ratio. Its good weldability and impact toughness make it suitable for dynamic loads and moderate climate conditions. Typical applications include:
- Construction & Infrastructure: Bridges, high-rise buildings, stadiums, crane girders
- Energy Sector: LSAW pipes for oil and gas pipelines, penstocks, pressure vessels, wind turbine towers
- Offshore & Marine: Jacket legs, deck structures, flare booms (with supplementary requirements)
- Machinery: Boiler drums, heavy equipment frames
Product Applications: Longitudinal Submerged Arc Welded (LSAW) pipes (oil/gas transmission, structural tubes), Welded plate girders and box columns, Pressure vessel shells and end plates, Penstock sections, Offshore platform structural members, Bridge deck panels and stiffeners
Processed into products: LSAW pipe spools and bends, Base plates, brackets, and flanges for heavy structures, Lifting lugs and pad eyes, Stiffening rings and diaphragms, Tubular joints for truss structures
Application industries: Civil Engineering & Construction, Oil & Gas (Pipeline), Power Generation (Hydro, Thermal, Wind), Shipbuilding & Marine, Heavy Machinery Manufacturing
JIS G3106 SM570 High-Tensile Steel for Welded Structures Similar / Alternative Materials with Comparable Performance
These grades offer slightly lower or higher strength levels but can be considered for replacement in less demanding applications, subject to design approval.
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM520 | Lower yield (≥ 365 MPa) and tensile (520-640 MPa); suitable for lighter loading |
| China | GB/T 1591 | Q420D | Yield ≥ 420 MPa; may be used if slight strength reduction is acceptable |
| Europe | EN 10025-2 | S420N / S420M | Yield ≥ 420 MPa; lower strength bracket |
| USA | ASTM A572/A572M | Grade 60 [415] | Yield ≥ 415 MPa; lower strength alternative |
| USA | ASTM A656/A656M | Grade 70 [480] | Yield ≥ 480 MPa, tensile ≥ 585 MPa; higher strength alternative with careful weldability |
Notes:
Weldability: Preheating and interpass temperature control are recommended according to carbon equivalent and section thickness. Post-weld heat treatment (PWHT) may be required for thick sections or pressure vessel applications.
Formability: SM570 can be cold formed with proper bending radii; for severe forming, hot forming or normalizing may be considered.
Inspection: LSAW pipes shall be tested to supplementary specifications such as dimensional checks, non-destructive testing (ultrasonic or radiographic) and hydrostatic test per applicable pipe standards (e.g., API 5L or project-specific specification).
Notes on data: Values are based on JIS G3106:2015 and typical physical properties. For certified data, refer to the respective standard and mill certificate.
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