JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil | Welded Structural Steel
Detailed material data sheet for JIS G3106 SM400A steel coil: chemical composition, mechanical and physical properties, international equivalents, and application guidance.
Hot rolling, cold forming, welding, cutting, machining, bending, stamping
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Introduction
SM400A is a carbon and low-alloy high-strength steel grade under Japanese Industrial Standard JIS G3106 for rolled steels in welded structures. It offers excellent weldability, moderate strength, and good formability. Supplied primarily as hot-rolled coils and plates, it is widely used in buildings, bridges, ships, and machinery. The steel combines a maximum carbon content of 0.23% (for thickness ≤50 mm) with controlled manganese to provide yield strengths from 175 to 245 MPa depending on thickness. Its balanced composition permits welding without preheating for most common sections, making it a cost-effective choice for general fabrication. SM400A is delivered in as-rolled or controlled rolled condition, with optional normalized treatment available upon agreement.
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Chemical Composition
The ladle analysis for SM400A according to JIS G3106 is given below. For thickness ≤50 mm, tighter carbon and manganese limits apply. Residual elements (Cr, Ni, Cu) are typically limited to 0.35% each unless otherwise agreed.
| Element | Standard Value (wt.%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.23 (t≤50 mm) | Thickness-dependent; see remarks |
| Carbon (C) | ≤0.25 (50 < t≤100 mm) | |
| Carbon (C) | ≤0.27 (100 < t≤200 mm) | |
| Silicon (Si) | ≤0.35 | All thickness ranges |
| Manganese (Mn) | 0.60 – 1.40 (t≤50 mm) | |
| Manganese (Mn) | 0.60 – 1.50 (50 < t≤100 mm) | |
| Manganese (Mn) | 0.70 – 1.50 (100 < t≤200 mm) | |
| Phosphorus (P) | ≤0.035 | |
| Sulfur (S) | ≤0.035 | |
| Residual elements (Cr, Ni, Cu each) | ≤0.35 typically | Optional specification; may be waived |
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Thermal and Electrical Physical Properties
Physical properties are typical for carbon structural steel (SM400A) at room temperature unless noted. Not mandatory in JIS G3106 but useful for design and thermal analysis. Slight variations may occur with processing history.
| Property | Typical Value | Unit | Condition/Remarks |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | 20°C |
| Elastic modulus (E) | 210 | GPa | Tension at 20°C |
| Shear modulus (G) | 80 | GPa | 20°C |
| Poisson's ratio (ν) | 0.30 | - | Within elastic range |
| Coefficient of thermal expansion (α) | 12.0 | ×10⁻⁶/K | 20–100°C |
| Thermal conductivity (λ) | 50 | W/(m·K) | At 20°C |
| Specific heat capacity (cp) | 460 | J/(kg·K) | At 20°C |
| Electrical resistivity (ρe) | 0.22 | µΩ·m | 20°C |
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Mechanical Properties
Mechanical properties as per JIS G3106 at ambient temperature. Yield strength and elongation depend on product thickness. Tensile test specimen and dimensions follow JIS Z 2241. Bend test requires no cracks on the outer surface after 180° bending.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength (ReH) | ≥245 | MPa | Thickness ≤16 mm |
| Yield strength (ReH) | ≥235 | MPa | Thickness >16 mm ≤40 mm |
| Yield strength (ReH) | ≥215 | MPa | Thickness >40 mm ≤75 mm |
| Yield strength (ReH) | ≥205 | MPa | Thickness >75 mm ≤100 mm |
| Yield strength (ReH) | ≥195 | MPa | Thickness >100 mm ≤160 mm |
| Yield strength (ReH) | ≥175 | MPa | Thickness >160 mm ≤200 mm |
| Tensile strength (Rm) | 400 – 510 | MPa | All thicknesses (t≤200 mm) |
| Elongation (A) | ≥23 | % | Thickness ≤5 mm; JIS No.5 specimen (gauge length 50 mm) |
| Elongation (A) | ≥18 | % | Thickness >5 mm ≤16 mm; JIS No.1A specimen (gauge length 200 mm) |
| Elongation (A) | ≥22 | % | Thickness >16 mm ≤40 mm; JIS No.1A specimen |
| Elongation (A) | ≥23 | % | Thickness >40 mm ≤75 mm; JIS No.4 specimen (gauge length 50 mm) |
| Elongation (A) | ≥24 | % | Thickness >75 mm ≤100 mm; JIS No.4 specimen |
| Elongation (A) | ≥24 | % | Thickness >100 mm ≤150 mm; JIS No.4 specimen |
| Bend test (180°) | d=1.5t (no cracks) | - | Thickness ≤16 mm |
| Bend test (180°) | d=2.0t (no cracks) | - | Thickness >16 mm |
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Fully Equivalent Material Standards and Alternative Grade Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM400A | Original specification |
| South Korea | KS D 3515 | SM400A | Identical to JIS |
| China | GB/T 1591 | Q275A | Similar tensile range; verify yield per thickness |
| Europe | EN 10025-2 | S275JR (1.0044) | Yield 275 MPa for t≤16 mm; tensile 410–560 MPa |
| USA | ASTM A36/A36M | A36 | Yield 250 MPa for t≤200 mm; tensile 400–550 MPa |
| International | ISO 630-2 | E275A | Comparable strength class |
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Application Introduction
SM400A is a versatile structural steel suitable for welded assemblies in ambient temperature service. It is widely used where cost-effective fabrication and good toughness are needed. The steel can be welded using all common arc processes without special preheating for thin sections (up to 50 mm when low-hydrogen electrodes are used). It is not intended for low-temperature notch-toughness duty (use SM400B or C for such applications).
Product Applications: Structural frames and columns for buildings, Bridge decks and girders, Hull plates and stiffeners for ships, Offshore platform modules, Welded pipes and tubular structures, Vehicle chassis and trailer frames, Industrial machine bases and supports
Processed into products: Welded I‑beams, H‑beams, and plate girders, Stiffener plates and gussets, Base plates and anchor plates, Flange and web plates for plate girders, Ship hull shell plates, bulkheads, Dump truck bodies and excavator buckets, Graded steel coil sections for roll‑forming
Application industries: Civil Engineering and Construction, Bridge Building, Shipbuilding and Marine Structures, Offshore Engineering, Automotive and Transportation, Machinery Manufacturing, Pressure Vessel and Storage Tanks
JIS G3106 SM400A Carbon & Low-Alloy High-Strength Steel Coil Similar / Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3106 | SM400B | Same strength; impact test mandatory |
| Japan | JIS G3106 | SM490A | Higher strength (490 MPa tensile range) |
| China | GB/T 700 | Q235B | Lower yield but widely used for structural work |
| Europe | EN 10025-2 | S235JR (1.0038) | Lower min. tensile; verify for specific gauge |
| USA | ASTM A572/A572M | Grade 50 | Higher strength; often used for welded structures |
| India | IS 2062 | E250 BR | Equivalent to Fe 410WA; yield 250 MPa |
Notes:
- Weldability: Excellent with all common methods; preheat only necessary when thickness >50 mm or when ambient temperature is below 5°C.
- Heat treatment: Normalizing may be applied to improve toughness; stress relieving at 550–650°C is recommended after heavy welding.
- Availability: Standard sizes as coils up to 12.7 mm, plates up to 200 mm; inquire for wider/heavier sections.
- Certification: Mill test certificates to EN 10204 3.1 upon request.
- Share
