JIS G3106 SM490A ERW Pipe
JIS G3106 SM490A ERW Pipe – Weldable Structural Steel for General Applications
SM490A ERW pipe manufactured to JIS G3106, a hot-rolled weldable structural steel with minimum yield strength 325 MPa for thickness ≤16 mm. Excellent weldability and toughness for general structures, bridges, and machinery.
Electric Resistance Welding (ERW), Hot Rolling, Normalizing (optional), Cold Forming, Welding, Machining
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JIS G3106 SM490A ERW Pipe Introduction
JIS G3106 SM490A ERW pipe is an electric-resistance-welded tubular product made from hot-rolled coils of SM490A steel. This carbon-manganese structural steel belongs to the SM490 series under Japanese Industrial Standard JIS G3106 (Rolled steels for welded structure). SM490A is characterized by a minimum tensile strength of 490–610 MPa and a minimum yield strength of 325 MPa for thicknesses up to 16 mm. It offers good weldability, moderate strength, and excellent formability, making it suitable for a wide range of structural and mechanical applications, including building columns, bridge members, vehicle frames, and general machinery. The "A" designation indicates the steel is supplied without specific impact requirements (as-rolled or normalized condition), offering a cost-effective solution for ambient-temperature service. The ERW pipe manufacturing process ensures uniform wall thickness and dimensional accuracy. Common delivery conditions are as-rolled or hot-finished ERW, with possible supplementary requirements per agreement.
JIS G3106 SM490A ERW Pipe Chemical Composition per JIS G3106
Ladle analysis limits for SM490A steel of thickness ≤100 mm. Values are maximum unless a range is shown. Carbon equivalent (CEV) may be specified upon agreement to ensure weldability. SM490A does not require impact-tested properties. The composition is designed for good balance of strength, ductility, and weldability.
| Element | Specified Value (max %) | Remarks |
|---|---|---|
| Carbon (C) | 0.20 | Thickness ≤50 mm; 0.22 for 50–100 mm |
| Silicon (Si) | 0.55 | |
| Manganese (Mn) | 1.65 | |
| Phosphorus (P) | 0.035 | |
| Sulfur (S) | 0.035 | |
| Ceq (optional) | 0.44 max (typical) | When required by agreement |
JIS G3106 SM490A ERW Pipe Thermal & Electrical Physical Properties
These values are typical for carbon-manganese structural steel at room temperature unless otherwise noted. Actual properties may vary slightly with specific processing and test direction. They are provided for design reference.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Elastic Modulus (E) | 205 – 210 | GPa | 20 °C, tensile |
| Shear Modulus (G) | 79 – 82 | GPa | 20 °C |
| Poisson's Ratio (ν) | 0.3 | Elastic range | |
| Thermal Expansion Coefficient (α) | 11.7 | 10⁻⁶ / K | 20–100 °C |
| Thermal Expansion Coefficient (α) | 12.5 | 10⁻⁶ / K | 20–200 °C |
| Thermal Expansion Coefficient (α) | 13.5 | 10⁻⁶ / K | 20–400 °C |
| Thermal Conductivity (λ) | 51 | W/(m·K) | 20 °C |
| Thermal Conductivity (λ) | 47 | W/(m·K) | 200 °C |
| Specific Heat Capacity (Cp) | 460 – 480 | J/(kg·K) | 20–200 °C |
| Electrical Resistivity (ρe) | 0.15 – 0.25 | µΩ·m | 20 °C |
JIS G3106 SM490A ERW Pipe Mechanical Properties per JIS G3106
Tensile properties for SM490A as rolled/ERW condition in longitudinal direction. Yield strength varies with thickness. Elongation is gauge-length dependent (No.5 test piece for plates/pipes, No.1A for full section). Bending test (flat-bend) is applicable for weld integrity (not mandatory for all products). No Charpy impact requirement for Grade A.
| Property | Specified Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 325 | MPa | Thickness ≤16 mm |
| Yield Strength (ReH) | ≥ 315 | MPa | Thickness >16–40 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | Thickness >40–75 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | Thickness >75–100 mm |
| Tensile Strength (Rm) | 490 – 610 | MPa | All thicknesses ≤100 mm |
| Elongation (A) | ≥ 22 | % | No.5 test piece, thickness ≤16 mm, gauge 50 mm |
| Elongation (A) | ≥ 17 | % | No.1A test piece, full section for pipes/plates ≤16 mm |
| Elongation (A) | ≥ 24 | % | No.5, thickness >16–40 mm |
| Elongation (A) | ≥ 23 | % | No.5, thickness >40 mm |
| Bend Test (180°) | d = 1.5a | For ERW pipe weld: d = 1.5a (a = pipe thickness); flange bend – no cracking |
JIS G3106 SM490A ERW Pipe Fully Equivalent International Standards & Substitutable Grades
| Country / Region | Standard | Grade / Designation | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490A | Original specification |
| Europe | EN 10025-2 | S355JR / S355J0 | JR: room-temp impact (27 J); J0: 0 °C impact (27 J). Chemical and strength similar. |
| USA | ASTM A572 / A709 | Grade 50 [345 MPa] | Yield 345 MPa, tensile ≥450 MPa; may need tighter S and P limits. |
| China | GB/T 1591 | Q345B | Yield 345 MPa for ≤16 mm, tensile 470-630 MPa. Widely used equivalent. |
| International | ISO 630 | Fe510C | Covers similar tensile range; Fe510D has impact requirements. |
| South Korea | KS D 3515 | SM490A | Korean standard identical to JIS |
JIS G3106 SM490A ERW Pipe Application Introduction
SM490A ERW pipe is a versatile structural tubular product suitable for welded, bolted, or riveted structures in general service. It is widely employed where moderate strength, good weldability, and cost efficiency are required. Typical applications include building columns and beams, bridge members, flood and retaining wall piling, sign poles, machinery frames, and various fabricated parts. The A-grade material is intended for use at ambient temperatures without impact-critical requirements. ERW pipe can be further processed by bending, flaring, and flattening without weld cracking.
Product Applications: Building columns and beams, Bridge girders and trusses, Pipe piles and foundation tubes, Light poles and sign supports, Storage racks and shelving systems, Vehicle chassis and trailer frames, Machine bases and support structures
Processed into products: Structural hollow sections for frames, Welded pipe assemblies, Brackets, stiffeners, and mounting plates, Conveyor belt rollers and idlers, Agricultural tool bars, Window and door frames (industrial), Exhaust stacks and handrails
Application industries: Construction & Infrastructure, Bridge & Highway Engineering, Shipbuilding & Offshore Structures (non-critical), Agricultural & Forestry Machinery, Automotive & Transport Frames, General Engineering & Fabrication
JIS G3106 SM490A ERW Pipe Closely Related / Similar Materials within JIS and Other Standards
| Country / Region | Standard | Grade / Designation | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM490B | Same strength, but impact tested at 0 °C (27 J min). Higher toughness version. |
| Japan | JIS G3106 | SM490C | Impact tested at –20 °C (47 J min). For low-temperature service. |
| Japan | JIS G3136 | SN490B | Structural steel for building frame with enhanced deformation capacity. |
| Japan | JIS G3114 | SMA490AW | Atmospheric corrosion-resistant steel with similar strength. |
| Europe | EN 10025-2 | S355K2 (-20 °C) | Higher toughness variant; may be used for more demanding applications. |
| USA | ASTM A500 | Grade C (345 MPa) | Cold-formed welded pipe, different chemistry but comparable strength. |
Notes:
ERW pipe specifics: SM490A ERW pipe is usually supplied with a weld seam fully normalized or heat-treated after welding to ensure uniform properties. Dimensions and tolerances follow JIS G3444 or G3452 for structural pipes, but the material properties are governed by JIS G3106. Limited corrosion resistance: unprotected steel will rust; galvanizing or painting is recommended for outdoor exposure. Machinability is typical of medium-carbon structural steel; preheating may be needed for thick sections (>50 mm) during welding. CEV control is advisable for welding to avoid cold cracking.
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