JIS G3106 SM400B LSAW Pipe
JIS G3106 SM400B LSAW Pipe: Chemical, Mechanical & Physical Properties, Equivalents and Applications
Comprehensive material analysis of JIS G3106 SM400B steel used for LSAW pipes: chemical composition, mechanical properties, thermal and electrical physical data, international equivalents, similar materials, and application guidance.
Submerged arc welding (LSAW), hot rolling, normalizing, cutting, cold bending, forming, edge preparation
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
JIS G3106 SM400B LSAW Pipe Introduction
JIS G3106 SM400B is a rolled steel for welded structures standardized by Japanese Industrial Standards. It is widely supplied in the form of plates, sheets, and sections, and is frequently manufactured into LSAW (Longitudinally Submerged Arc Welded) pipe for demanding structural applications. This grade belongs to the SM400 series, with the designation 'B' guaranteeing minimum Charpy impact energy of 27 J at 0 °C, which distinguishes it from the basic SM400A grade. The steel has a moderate carbon content and controlled manganese range, ensuring excellent weldability and good balance between strength and toughness. Typical mechanical properties include yield strengths from 215 MPa to 245 MPa depending on thickness, tensile strength between 400 MPa and 510 MPa, and reliable elongation values.
- Excellent weldability due to low carbon equivalent, suitable for submerged arc welding without excessive preheating.
- Guaranteed notch toughness at 0 °C, making it suitable for outdoor and cold-climate structures.
- Good formability for cold bending and fabrication, with specified bend test requirements.
- LSAW pipes made from SM400B provide cost-effective solutions for fluid transport and structural columns.
JIS G3106 SM400B LSAW Pipe Chemical Composition
Chemical requirements according to JIS G3106:2004 for SM400B. Values vary with product thickness; two thickness ranges are specified. The steel is intentionally non-microalloyed, with only carbon, silicon, manganese, phosphorus and sulfur controlled. Low carbon equivalent contributes to weldability.
| Element | Specified Value (wt%) | Notes |
|---|---|---|
| C | ≤0.20 | Thickness ≤50 mm |
| C | ≤0.22 | 50 < thickness ≤100 mm |
| Si | ≤0.35 | All thicknesses up to 100 mm |
| Mn | 0.60–1.40 | Thickness ≤50 mm |
| Mn | 0.60–1.50 | 50 < thickness ≤100 mm |
| P | ≤0.035 | |
| S | ≤0.035 |
JIS G3106 SM400B LSAW Pipe Thermal and Electrical Physical Properties
Physical constants are not specified in JIS G3106 but are representative for this type of low‑carbon structural steel. These values are suitable for engineering calculations involving thermal expansion, heat transfer, and structural dynamics. Actual values may vary slightly depending on exact composition and heat treatment condition.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | at 20 °C |
| Modulus of Elasticity (E) | 200–210 | GPa | at 20 °C |
| Shear Modulus (G) | ~80 | GPa | at 20 °C |
| Poisson's Ratio (ν) | 0.3 | – | at 20 °C |
| Thermal Expansion Coefficient (α) | 10.8 | 10⁻⁶/K | 20–100 °C |
| Thermal Expansion Coefficient (α) | 12.0 | 10⁻⁶/K | 20–200 °C |
| Thermal Expansion Coefficient (α) | 12.9 | 10⁻⁶/K | 20–300 °C |
| Thermal Conductivity (λ) | 50 | W/(m·K) | at 20 °C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | at 20 °C |
| Electrical Resistivity (ρ_e) | 0.17–0.22 | μΩ·m | at 20 °C |
JIS G3106 SM400B LSAW Pipe Mechanical Properties
Tensile and impact properties as specified in JIS G3106 for SM400B. The values apply to the longitudinal direction (parallel to rolling/pipe axis). For thicknesses ≤12 mm the Charpy impact test is not mandatory and may be agreed upon. Bend test uses a mandrel with diameter relative to thickness, 180° bending angle. Elongation specimens vary: JIS No.5 for t≤5 mm, JIS No.1A or No.4 for thicker material.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥245 | MPa | t ≤16 mm, longitudinal |
| Yield Strength (ReH) | ≥235 | MPa | 16 < t ≤40 mm, longitudinal |
| Yield Strength (ReH) | ≥215 | MPa | 40 < t ≤75 mm, longitudinal |
| Yield Strength (ReH) | ≥215 | MPa | 75 < t ≤100 mm, longitudinal |
| Tensile Strength (Rm) | 400–510 | MPa | All thicknesses, longitudinal |
| Elongation (A) | ≥23 | % | t ≤5 mm, JIS No.5 specimen |
| Elongation (A) | ≥18 | % | 5 < t ≤16 mm, JIS No.1A specimen |
| Elongation (A) | ≥22 | % | 16 < t ≤50 mm, JIS No.1A specimen |
| Elongation (A) | ≥26 | % | 16 < t ≤50 mm, JIS No.4 specimen |
| Bend Test (mandrel diameter) | 1.5 × thickness | – | t ≤16 mm, 180° bend |
| Bend Test (mandrel diameter) | 2.0 × thickness | – | 16 < t ≤100 mm, 180° bend |
| Charpy Impact Energy (KV₂) | ≥27 | J | 0 °C, V-notch, longitudinal, t >12 mm |
JIS G3106 SM400B LSAW Pipe Exactly Matching Grades and Replaceable Equivalents
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM400B | Original specification |
| South Korea | KS D 3515 | SM400B | Technically identical to JIS grade |
| Taiwan | CNS 2947 | SM400B | Identical chemical and mechanical properties |
| USA | ASTM A36/A36M | A36 (supplementary) | Similar strength; must specify Supplementary Requirement S5 for Charpy at 0 °C to match impact requirement |
| Europe | EN 10025-2 | S235J0 | Yield ≥235 MPa, tensile 360–510 MPa, impact 27 J at 0 °C; chemistry differs (e.g., higher Mn permitted) |
| China | GB/T 1591 | Q235C | Yield ≥235 MPa, tensile 370–500 MPa, Charpy 27 J at 0 °C; approximate substitution with careful review |
JIS G3106 SM400B LSAW Pipe Application Introduction
SM400B steel in LSAW pipe form is utilized across a range of structural and industrial applications where reliable weldability and moderate strength are essential. Its guaranteed toughness at 0 °C makes it suitable for outdoor and cold‑region construction. The material can be easily cut, welded, and formed, allowing fabrication of complex assemblies.
Product Applications: Large-diameter LSAW welded pipes for structural columns, Piling pipes and foundation casings, Bridge truss members and arches, Offshore platform legs and braces, Conduits for water and low-pressure fluids, Steel pipe piles and jetties, Structural hollow sections for buildings
Processed into products: Flanges and blind flanges for pipe connections, Pipe reducers, elbows, and tees, Gusset plates and stiffeners in welded nodes, Base plates and end plates for columns, Tubular tower sections, Fabricated beam-to-column connections, Wind bracing elements
Application industries: Building and construction, Bridge engineering, Offshore and marine structures, Shipbuilding, Construction and heavy machinery, Water and wastewater infrastructure, Port and harbor facilities
JIS G3106 SM400B LSAW Pipe Closest Substitute Materials with Slightly Different Properties
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM400C | Identical strength but Charpy at 0 °C with higher guaranteed energy (47 J), better toughness |
| Japan | JIS G3101 | SS400 | General structural steel; yield/tensile comparable, but no Charpy requirement; not recommended for dynamic loading |
| Europe | EN 10025-2 | S275J0 | Higher yield (275 MPa) and tensile (410–560 MPa), impact at 0 °C; can replace SM400B where increased strength is acceptable |
| USA | ASTM A572/A572M | Grade 42 (290) | Yield 290 MPa; higher strength, suitable when lightweight design is needed and weldability is confirmed |
| International | ISO 630-2 | S235B | Similar strength, impact test at 0 °C (27 J); chemical composition close, can be used as alternative in many projects |
Notes:
Welding consumables: When fabricating SM400B LSAW pipes, matching filler metals such as AWS A5.17 F7A0-EL12 or equivalent should be used to ensure sound joints and toughness. Heat treatment: Post-weld stress relieving may be applied at 600–650 °C for thick-walled structures to reduce residual stresses. Non-destructive testing: Longitudinal and circumferential welds are typically inspected by ultrasonic or radiographic methods as per relevant codes (e.g., API 5L, JIS G 0404). Pressure containment: For fluid service, additional requirements like hydrostatic testing and material toughness at design temperature must be considered; SM400B may be suitable for low‑pressure water pipelines but not for sour or high‑pressure gas service without further evaluation. Availability: LSAW pipes in SM400B are commonly produced with outside diameters from 406 mm (16 in) upward and wall thicknesses up to approximately 50 mm.
- Share
