JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil - Specs, Equivalents
SM570 steel is a Japanese carbon and low-alloy high-strength structural steel defined in JIS G3106, offering a minimum yield strength of 460 MPa, excellent weldability, and widely used in bridges, buildings, and heavy machinery.
Hot rolling, welding, forming, cutting, machining
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JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Introduction
SM570 is a carbon and low-alloy high-strength structural steel grade specified in JIS G3106 (Rolled steels for welded structure). It provides a minimum yield strength of 460 MPa and tensile strength in the range of 570–720 MPa. The alloy design ensures good weldability, ductility, and notch toughness, making it well suited for welded structures subjected to moderate loads and dynamic stresses. Typical applications include bridge components, building frames, offshore structures, shipbuilding, and heavy equipment. The steel is usually delivered in hot-rolled condition as coils, plates, or strips, and can be supplied in as-rolled or normalized states according to customer requirements. Its balanced chemical composition, with restricted carbon and manganese contents and controlled impurity levels, promotes reliable weld performance and resistance to brittle fracture.
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Chemical Composition
The chemical composition of SM570 steel is defined in JIS G3106:2015. The values below represent the maximum allowable contents for heat analysis. The steel is a carbon-manganese low‑alloy grade with tight control on phosphorus and sulfur to ensure good weldability and toughness. Additional microalloying elements (e.g., Nb, V, Ti) may be added at the manufacturer's discretion to meet mechanical property requirements but are not specified in the standard.
| Element | Standard Value (max) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.18 % | Heat analysis |
| Silicon (Si) | ≤ 0.55 % | Heat analysis |
| Manganese (Mn) | ≤ 1.60 % | Heat analysis |
| Phosphorus (P) | ≤ 0.035 % | Heat analysis |
| Sulfur (S) | ≤ 0.035 % | Heat analysis |
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Thermal and Electrical Physical Properties
The following physical property data are typical for low‑alloy structural steels and are provided as design reference values. They are not mandatory requirements in JIS G3106 but are representative of the SM570 grade at room temperature unless otherwise noted.
| Property | Standard Reference Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Elastic Modulus (E) | 206 | GPa | At 20 °C |
| Shear Modulus (G) | 79.3 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.30 | – | At 20 °C |
| Thermal Expansion Coefficient (α) | 12.0 × 10⁻⁶ | 1/K | 20–100 °C |
| Thermal Conductivity (λ) | 45 | W/(m·K) | At 20 °C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | At 20 °C |
| Electrical Resistivity (ρₑ) | 0.16 × 10⁻⁶ | Ω·m | At 20 °C |
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Mechanical Properties
The mechanical properties of SM570 steel are taken from JIS G3106:2015. Requirements vary with product thickness. The steel is typically subjected to tensile and bend tests and may undergo Charpy V‑notch impact testing if specified. The yield strength decreases as thickness increases, while the tensile strength remains between 570 and 720 MPa for all thicknesses up to 100 mm. Elongation requirements depend on the thickness and the type of test specimen.
| Property | Standard Required Value | Unit | Test Condition (Thickness t, mm) |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 460 | MPa | t ≤ 16 |
| Yield Strength (ReH) | ≥ 450 | MPa | 16 < t ≤ 40 |
| Yield Strength (ReH) | ≥ 430 | MPa | 40 < t ≤ 75 |
| Yield Strength (ReH) | ≥ 420 | MPa | 75 < t ≤ 100 |
| Tensile Strength (Rm) | 570 – 720 | MPa | t ≤ 100 |
| Elongation (A) | ≥ 19 | % | t ≤ 5 (test piece No. 5) |
| Elongation (A) | ≥ 26 | % | 5 < t ≤ 16 (test piece No. 5) |
| Elongation (A) | ≥ 20 | % | 16 < t ≤ 50 (test piece No. 5 or 1A) |
| Bend Test (180°) | d = 1.5 t | – | t ≤ 16 |
| Bend Test (180°) | d = 2.0 t | – | 16 < t ≤ 25 |
| Bend Test (180°) | d = 2.5 t | – | 25 < t |
| Charpy V-notch Impact Energy (KV₂) | ≥ 47 (longitudinal) | J | At 0 °C (optional, typically specified) |
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Fully Equivalent International Standards and Alternative Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM570 | Original specification |
| Europe | EN 10025-4 | S460M | Thermo-mechanically rolled weldable fine grain structural steel, similar strength and weldability; slight chemistry differences may exist. |
| China | GB/T 1591 | Q460C/Q460D/Q460E | High-strength low-alloy structural steel, comparable yield strength; toughness classes match different temperature requirements. |
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Application Introduction
SM570 is designed for welded structures where a good combination of strength, toughness, and weldability is required. It is extensively used in heavy civil and industrial engineering projects. The following lists highlight typical applications, products, and components made from this grade.
Product Applications: Welded H-beams, I-beams and box columns, Bridge girders and truss elements, Crane booms and jibs, Excavator arms and bulldozer blades, Wind turbine towers and foundation components, Ship hull plates and structural bulkheads, Pressure vessels and penstocks
Processed into products: Flanges and webs of large welded beams, Stiffeners and gusset plates in bridges, Reinforcing plates for heavy equipment frames, Connection nodes and brackets in steel structures, Rolled cylindrical shells for towers and vessels, Forged or welded structural joints for fatigue‑critical applications
Application industries: Bridge engineering, Building and construction, Shipbuilding and marine structures, Offshore platforms and wind towers, Heavy machinery and earthmoving equipment, Pressure vessel and storage tank manufacturing, Railway vehicles and infrastructure
JIS G3106 SM570 Carbon and Low-alloy High-strength Steel Coil Similar / Alternative Materials with Close Properties
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM520 | Lower strength grade (YS ≥365 MPa, TS 520–640 MPa) from the same standard, suitable for less demanding applications. |
| Europe | EN 10025-3 | S460N/S460NL | Normalized fine grain steels with slightly different delivery condition but similar mechanical properties. |
| USA | ASTM A572 | Grade 65 | High-strength low-alloy steel with min. YS 450 MPa; often used as an alternative where slightly lower strength is acceptable. |
| International | ISO 4950-2 | S460M | Similar thermo-mechanically rolled high strength steel in the ISO system, essentially the same as EN S460M. |
Notes:
When using SM570 steel, proper welding procedures should be followed, including selection of appropriate filler metals (e.g., matching high-strength electrodes) and preheating for thicker sections to avoid cold cracking. For thicknesses above 50 mm, supplementary Charpy impact test requirements are often agreed upon between the purchaser and manufacturer. The carbon equivalent value (CEV) is typically controlled to ≤ 0.44% for improved weldability, although this is not a mandatory chemical requirement in the standard but a supplementary arrangement. It is recommended to consult the latest edition of JIS G3106 for full details and any updates.
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