SM520B High-Strength Steel Coil
JIS G3106 SM520B High-Strength Steel Coil: Properties, Equivalents & Applications
Detailed material data for JIS G3106 SM520B carbon and low-alloy high-strength steel coil, including chemical composition, mechanical properties, thermal and electrical properties, international equivalents, and application guide.
Welding, hot forming, cutting, machining, cold forming (appropriate for thickness), hot-dip galvanizing
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SM520B High-Strength Steel Coil Introduction
SM520B is a weldable high-strength structural steel grade specified in Japanese Industrial Standard JIS G3106. It is commonly supplied as hot-rolled coil, plate, or sheet. The steel combines good weldability with a minimum yield strength of 365 MPa (for thickness ≤16 mm) and tensile strength of 520–640 MPa. It contains grain-refining elements (Nb, V, Ti) to ensure fine ferritic grain size and good notch toughness at 0°C (Charpy V-notch 27 J min). SM520B is widely used in welded structures such as bridges, buildings, offshore platforms, and heavy machinery.
SM520B High-Strength Steel Coil Chemical Composition
Chemical composition according to JIS G3106. SM520B is a grain-refined steel; it must contain at least one grain-refining element (Nb, V, Ti) with a minimum of 0.005% each when added. The carbon equivalent (CE) is limited to ensure weldability.
| Chemical Element | Standard Value (wt.%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.20 | |
| Silicon (Si) | ≤0.55 | |
| Manganese (Mn) | ≤1.60 | |
| Phosphorus (P) | ≤0.035 | |
| Sulfur (S) | ≤0.035 | |
| Niobium (Nb) | ≥0.005 (if added) | Grain-refining element; min 0.005% when used alone or in combination |
| Vanadium (V) | ≥0.005 (if added) | Grain-refining element; min 0.005% when used alone or in combination |
| Titanium (Ti) | ≥0.005 (if added) | Grain-refining element; min 0.005% when used alone or in combination |
| Carbon Equivalent (CE) | ≤0.40 (t≤50mm), ≤0.42 (50| CE = C + Mn/6 + Si/24 + Ni/40 + Cr/5 + Mo/4 + V/14 | |
SM520B High-Strength Steel Coil Thermal and Electrical Physical Properties
JIS G3106 does not mandate thermal or electrical physical properties. The steel is not designed for applications requiring guaranteed physical constants. Typical values for similar carbon-manganese structural steels (density ~7.85 g/cm³, elastic modulus ~206 GPa, etc.) can be used for design reference but are not part of the standard.
| Property | Standard Requirement | Unit | Test Condition |
|---|
SM520B High-Strength Steel Coil Mechanical Properties
Mechanical properties for SM520B steel according to JIS G3106. Tensile test specimens are taken in the transverse direction; yield strength and tensile strength vary with thickness. Charpy impact test is performed on longitudinal specimens at 0°C. Bending test requires 180° bend without cracking.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥365 | MPa | Thickness ≤16 mm |
| Yield Strength (ReH) | ≥355 | MPa | 16 mm < Thickness ≤40 mm |
| Yield Strength (ReH) | ≥335 | MPa | 40 mm < Thickness ≤75 mm |
| Yield Strength (ReH) | ≥325 | MPa | 75 mm < Thickness ≤100 mm |
| Tensile Strength (Rm) | 520 – 640 | MPa | Thickness ≤100 mm |
| Elongation (A) | ≥15 | % | Thickness ≤5 mm, JIS No.5 specimen |
| Elongation (A) | ≥15 | % | 5 mm < Thickness ≤16 mm, JIS No.5 specimen |
| Elongation (A) | ≥19 | % | 16 mm < Thickness ≤50 mm, JIS No.1A specimen |
| Elongation (A) | ≥19 | % | 50 mm < Thickness ≤100 mm, JIS No.1A specimen |
| Elongation (A) | ≥17 | % | 50 mm < Thickness ≤100 mm, JIS No.10 specimen (alternative) |
| Bend Test (180°) | No cracks; bending radius = 3a | - | Thickness ≤16 mm, a = specimen thickness |
| Bend Test (180°) | No cracks; bending radius = 3.5a | - | 16 mm < Thickness ≤100 mm |
| Charpy Impact Energy (KV, longitudinal) | ≥27 | J | 0 °C, V-notch |
SM520B High-Strength Steel Coil Identical International Equivalents and Direct Replacement Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International (ISO) | ISO 630-2 | E355B | Identical chemical and mechanical requirements; Charpy V-notch at 0°C, min 27 J; yield 355 MPa (t≤16 mm), tensile 470–630 MPa. Matches SM520B tolerance ranges. |
| Japan | JIS G3106 | SM520B | Original specification. |
SM520B High-Strength Steel Coil Application Introduction
SM520B is designed for welded structures requiring high strength and good low-temperature toughness. It can be fabricated into a variety of components using conventional welding, cutting, and forming processes. When welding, low-hydrogen procedures are recommended to avoid cold cracking, and preheating may be necessary for thicker sections. The steel is not intended for heat treatment to enhance strength but can be normalized or stress-relieved.
Product Applications: Structural steel beams and columns, Bridge girders and decks, Ship hull plates and frames, Offshore platform legs and braces, Crane booms, Wind turbine towers, Pressure vessel shells, Storage tank walls
Processed into products: Welded built-up sections, Flanges and webs of plate girders, Box columns, Penstock pipes, Loader arms, Chassis frames for heavy vehicles, Boiler drums (with impact test agreement), Anchor bolts and base plates (thick plates)
Application industries: Building and civil engineering, Bridge construction, Shipbuilding and marine structures, Offshore platforms, Heavy machinery and equipment, Railway vehicles, Storage tanks and pressure vessels, Industrial steel structures
SM520B High-Strength Steel Coil Similar and Comparable Material Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| European Union | EN 10025-2 | S355J0 | Yield 355 MPa, tensile 470–630 MPa; Charpy 0°C, min 27 J. Slightly lower yield and tensile range; often considered a functional equivalent for structural applications. |
| China | GB/T 1591 | Q345B | Yield 345 MPa (t≤16 mm), tensile 470–630 MPa; Charpy 20°C, min 27 J (B level). Lower yield and impact temperature; check project requirements. |
| USA | ASTM A572/A572M | Grade 50 [345] | Yield 345 MPa, tensile 450 MPa min. Lower strength levels; may be acceptable after re-design. Charpy test optional. |
| India | IS 2062 | E350 BR/B0 | Yield 350 MPa, tensile 490 MPa min; notch toughness at 0°C. Comparable high-strength structural steel. |
Notes:
Ordering information: SM520B is typically supplied in the as-rolled condition. If impact testing at 0°C is required, it must be specified. For thicknesses above 40 mm, normalizing or controlled rolling may be agreed upon. Weldability: Low carbon equivalent (CE ≤0.42%) indicates good weldability. However, preheat and interpass temperature control may be needed based on thickness, heat input, and hydrogen level. Surface quality: According to JIS G3106, the steel surface shall be free from harmful defects. Supplementary requirements for ultrasonic testing can be agreed upon.
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