JIS G3106 SM400B ERW Pipe
SM400B ERW Pipe - JIS G3106 Welding Structural Carbon Steel Pipe
Comprehensive material data for SM400B electric resistance welded pipe according to JIS G3106, including chemical composition, mechanical properties, thermal and electrical physical properties, international equivalents, and application guidance.
Cutting, bending, welding, machining, drilling, galvanizing, painting
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JIS G3106 SM400B ERW Pipe Introduction
SM400B is a carbon steel grade specified in JIS G3106 for welded structural use. It is commonly produced as ERW (Electric Resistance Welded) pipe, offering good weldability, moderate strength, and reliable toughness at 0°C. Key characteristics:
- Minimum yield strength of 245 MPa for thicknesses ≤16 mm
- Tensile strength range of 400–510 MPa
- Guaranteed Charpy impact energy of 27 J at 0°C
- Excellent cold formability and weldability
SM400B ERW pipe is widely used in building frames, bridges, industrial machinery, and general structural applications where reliability and cost-effectiveness are required.
JIS G3106 SM400B ERW Pipe Chemical Composition
Chemical composition of SM400B according to JIS G3106 for thicknesses up to 200 mm. Carbon equivalent (CEV) is limited to ensure good weldability. Residual elements are controlled to meet specified mechanical and toughness requirements.
| Element | Standard Value (wt%) | Remarks |
|---|---|---|
| C | ≤ 0.20 (t ≤ 50 mm); ≤ 0.22 (50 < t ≤ 200 mm) | Ladle analysis |
| Si | ≤ 0.35 | |
| Mn | 0.60 ~ 1.50 (t ≤ 50 mm); 0.60 ~ 1.60 (50 < t ≤ 200 mm) | For product analysis, tolerances per JIS G0321 apply |
| P | ≤ 0.035 | |
| S | ≤ 0.035 | |
| CEV | ≤ 0.38 (t ≤ 40 mm) | CEV = C + Mn/6 + (Cu+Ni)/15 + (Cr+Mo+V)/5; optional for thickness >40 mm |
JIS G3106 SM400B ERW Pipe Thermal and Electrical Physical Properties
Typical physical properties for carbon steel at room temperature unless otherwise noted. These values are representative for SM400B grade and may vary slightly with exact composition and microstructure. Density and elastic modulus are essential for structural design.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20°C |
| Elastic Modulus (E) | 205 | GPa | 20°C |
| Shear Modulus (G) | 79 | GPa | 20°C |
| Poisson's Ratio (ν) | 0.29 | — | 20°C |
| Thermal Expansion Coefficient (α) | 11.8 | 10−⁸ /K | 20~100°C |
| Thermal Expansion Coefficient (α) | 12.5 | 10−⁸ /K | 20~200°C |
| Thermal Expansion Coefficient (α) | 13.3 | 10−⁸ /K | 20~300°C |
| Thermal Conductivity (λ) | 51.9 | W/(m·K) | 20°C |
| Specific Heat Capacity (c) | 486 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρe) | 0.16 | Ω·mm²/m | 20°C |
JIS G3106 SM400B ERW Pipe Mechanical Properties
Mechanical properties for SM400B steel plate/strip based on JIS G3106. Values for ERW pipe should be verified against applicable pipe standard (e.g., JIS G3444 STK400) which may have similar or slightly adjusted requirements depending on forming and welding procedures. Tensile test specimen orientation is longitudinal.
| Property | Standard Requirement | Unit | Test Condition / Thickness |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 245 | MPa | t ≤ 16 mm |
| Yield Strength (ReH) | ≥ 235 | MPa | 16 < t ≤ 40 mm |
| Yield Strength (ReH) | ≥ 215 | MPa | 40 < t ≤ 100 mm |
| Tensile Strength (Rm) | 400 ~ 510 | MPa | All t |
| Elongation (A) | ≥ 21 (No.1A specimen) | % | t ≤ 5 mm (gauge length 50 mm) |
| Elongation (A) | ≥ 23 (No.1A specimen) | % | 5 < t ≤ 16 mm (gauge length 50 mm) |
| Elongation (A) | ≥ 20 (No.1A specimen) | % | 16 < t ≤ 50 mm |
| Bend Test (180° bend) | No cracks | — | Bend diameter = 1.5×thickness (t ≤ 25 mm); inner bend radius = 1.5t |
| Charpy Impact (KV2, longitudinal) | ≥ 27 | J | 0°C, V-notch, full-size specimen (10×10 mm) |
JIS G3106 SM400B ERW Pipe Fully Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM400B | Base standard for plate, sheet, sections, bars; also applicable to ERW pipe when specified |
| Japan | JIS G3444 | STK400 | General structural carbon steel pipe; interchangeable with SM400B for welded tubular structures |
| International | ISO 630-2 | E235B | Similar chemical and mechanical properties with guaranteed 0°C impact (27 J) |
| China | GB/T 700 | Q235B | Direct equivalent for general structural use; impact test at 20°C or with supplementary requirement for 0°C |
| Europe | EN 10025-2 | S235JR+S235J0 | S235JR (without impact) and S235J0 (27 J at 0°C) equivalents depending on toughness requirement |
| USA | ASTM A36/A36M | A36 | Often used as equivalent; A36 does not mandate impact test, but can be supplied with Charpy option |
JIS G3106 SM400B ERW Pipe Application Introduction
SM400B ERW pipe is a versatile carbon steel product designed for welded structural applications. It can replace hot-rolled sections in many frameworks. Typical applications span:
- Building columns, beams, and trusses
- Bridge piers and superstructures
- Machinery frames and support structures
- Infrastructure such as lighting poles, sign gantries
- Construction of temporary structures and scaffolding
The material is readily weldable using common processes (SMAW, GMAW, SAW) and can be galvanized for corrosion protection. ERW pipe form allows efficient use of material, uniform wall thickness, and ease of connection by bolting or welding.
Product Applications: ERW structural pipe (round, square, rectangular), Hollow structural sections (HSS), Tubular struts and bracing, Welded frames for machinery, Construction scaffolding tubes, Pipe piling, Conveyor rollers
Processed into products: Support columns for buildings, Bridge chords and diagonals, Crane booms and lattice structures, Automotive seat frames and bumper reinforcements, Material handling equipment frames, Racking legs and beams, Agricultural equipment frames
Application industries: Civil engineering and construction, Bridge building, Industrial machinery manufacturing, Automotive (subframes, trailer hitches), Storage and racking systems, Renewable energy (wind turbine towers, solar trackers)
JIS G3106 SM400B ERW Pipe Similar/Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM400A | Lower toughness (no impact test), otherwise similar mechanical properties; suitable for less demanding applications |
| Japan | JIS G3106 | SM400C | Higher toughness (impact test at 0°C, same as SM400B); SM400B is more commonly used |
| Japan | JIS G3101 | SS400 | General structural carbon steel without guaranteed impact; often used as a default substitute where toughness is not critical |
| Europe | EN 10025-2 | S235J2 | Impact energy 27 J at -20°C; superior low-temperature toughness for demanding environments |
| USA | ASTM A500/A500M | Grade B | Cold-formed welded structural tubing with similar strength; not direct equivalent but used in similar applications |
| China | GB/T 1591 | Q345B | Higher strength low-alloy steel (yield ≥345 MPa); suitable when weight savings or higher load capacity is needed |
Notes:
ERW pipe specific notes: When SM400B is supplied as ERW pipe, the weld seam should meet the same mechanical requirements as the base metal. Non-destructive testing (such as eddy current or ultrasonic) is normally performed. Welding procedure qualifications are recommended. For thicknesses above 40 mm, normalizing may be advised to refine grain structure. Corrosion protection: Hot-dip galvanizing or painting is typical unless the environment is non-corrosive. JIS G3106 SM400B ERW pipe can be ordered with supplementary requirements such as Charpy impact at -20°C or with increased CEV limits, subject to agreement between purchaser and manufacturer.
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