JIS G3114 SMA400CP Weather Resistant Steel Plate
JIS G3114 SMA400CP Weather Resistant Steel Plate - Enhanced Atmospheric Corrosion Resistance for Welded Structures
Explore JIS G3114 SMA400CP, a high-strength weather resistant steel plate with minimum yield strength 400 MPa, designed for welded structures, offering excellent corrosion resistance in atmospheric environments. Ideal for painted and unpainted applications.
Welding, bending, cutting, machining, and hot-dip galvanizing after suitable surface preparation
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JIS G3114 SMA400CP Weather Resistant Steel Plate Introduction
SMA400CP is a hot-rolled atmospheric corrosion resisting steel for welded structures as specified in Japanese Industrial Standard JIS G3114. This grade belongs to the SMA400 group with a minimum yield strength of 400 N/mm² and carries the suffix 'C' indicating Charpy impact testing at -20°C, and 'P' denoting suitability for painted applications. Key features include:
- Excellent weldability and toughness for structural reliability
- Superior atmospheric corrosion resistance through alloying elements Cu, Cr, Ni
- Available in a wide range of thicknesses and product forms
SMA400CP is primarily used in bridges, buildings, containers, and other outdoor exposed structures where long service life with minimal maintenance is essential.
JIS G3114 SMA400CP Weather Resistant Steel Plate Chemical Composition
The chemical composition of SMA400CP complies with JIS G3114 for product thickness ≤50 mm. The steel contains deliberate additions of copper, chromium, and nickel to form a dense, adherent patina that resists further corrosion, thereby extending service life in atmospheric exposure. Phosphorus and sulfur are kept low to ensure good hot workability and weldability.
| Element | Specified Value (%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.18 | Typical for ≤50 mm thickness |
| Silicon (Si) | 0.15 – 0.65 | |
| Manganese (Mn) | ≤1.40 | For thickness ≤50 mm |
| Phosphorus (P) | ≤0.035 | |
| Sulfur (S) | ≤0.035 | |
| Copper (Cu) | 0.30 – 0.50 | Weathering element |
| Chromium (Cr) | 0.45 – 0.75 | Weathering element |
| Nickel (Ni) | 0.05 – 0.30 | Weathering element |
JIS G3114 SMA400CP Weather Resistant Steel Plate Thermal and Electrical Physical Properties
These physical properties are not mandatory requirements of JIS G3114 but represent typical values for weathering steel of the SMA400 type. They are useful for design calculations involving heat transfer, thermal expansion, and electromagnetic behaviour. Data are based on published technical literature from major steel producers.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At room temperature |
| Modulus of Elasticity (E) | 205 | GPa | Room temperature |
| Shear Modulus (G) | 80 | GPa | Estimated |
| Poisson's Ratio (ν) | 0.3 | - | In elastic range |
| Thermal Expansion Coefficient (α) | 12.0 | ×10⁻⁶/K | 20–100°C |
| Thermal Conductivity (λ) | 45 | W/(m·K) | At 20°C |
| Specific Heat Capacity (cₚ) | 0.46 | J/(g·K) | Around 20°C |
| Electrical Resistivity (ρₑ) | 0.25 | µΩ·m | At 20°C |
JIS G3114 SMA400CP Weather Resistant Steel Plate Mechanical Properties
Mechanical properties are determined on test specimens taken in accordance with JIS G3114. Tensile testing is performed at ambient temperature. The Charpy V-notch impact test is mandatory for grade 'C' at -20°C. Bending tests demonstrate formability without cracking. Values vary with product thickness; the table lists the most commonly supplied thickness ranges.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥400 | N/mm² | Thickness ≤16 mm |
| Yield Strength (ReH) | ≥390 | N/mm² | Thickness 16 < t ≤40 mm |
| Yield Strength (ReH) | ≥375 | N/mm² | Thickness 40 < t ≤75 mm |
| Yield Strength (ReH) | ≥355 | N/mm² | Thickness 75 < t ≤100 mm |
| Yield Strength (ReH) | ≥335 | N/mm² | Thickness 100 < t ≤160 mm |
| Yield Strength (ReH) | ≥315 | N/mm² | Thickness 160 < t ≤200 mm |
| Tensile Strength (Rm) | 490 – 610 | N/mm² | All thicknesses |
| Elongation (A) | ≥21 | % | JIS No.5 specimen, t 5–16 mm |
| Elongation (A) | ≥15 (t ≤20 mm), ≥17 (t >20 mm) | % | JIS No.1A specimen, t 16–50 mm |
| Charpy Impact Energy (KV₂) | ≥27 (average of 3 specimens) | J | Test temp. -20°C, 10×10 mm specimen |
| Bend Test | No cracks, 180° bend, inner radius 0.5t | - | Thickness ≤16 mm |
| Bend Test | No cracks, 180° bend, inner radius 1.0t | - | Thickness 16 < t ≤100 mm |
JIS G3114 SMA400CP Weather Resistant Steel Plate Fully Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3114 | SMA400CP | Original standard |
| South Korea | KS D 3529 | SMA400CP | Identical adoption of JIS |
| Taiwan | CNS 4620 | SMA400CP | Harmonized with JIS |
| China | GB/T 4171 | Q415GNH | Comparable weather resistance, yield ~415 N/mm² |
| ISO | ISO 4952 | S420W | Similar strength and weathering class |
JIS G3114 SMA400CP Weather Resistant Steel Plate Application Introduction
SMA400CP is a versatile weather‑resistant structural steel that combines high strength with excellent weldability and corrosion resistance in unpainted or painted condition. Its typical service life in atmospheric exposure can reach several decades without maintenance if properly detailed. Guidelines for application:
- Ensure proper drainage and ventilation to allow cyclic wet/dry conditions that form a protective patina
- Avoid prolonged contact with stagnant water or buried conditions without supplementary protection
- Can be welded with all common processes using low‑hydrogen consumables matched to the base strength
- Pre‑heating may be required for thick sections (>50 mm) to avoid hydrogen cracking
Product Applications: Weather‑resistant steel plates and cut‑to‑length parts, Welded beams, columns, and trusses, Box girders for bridge decks, Rolled structural sections (angles, channels, I‑beams), Pre‑fabricated building modules
Processed into products: Bridge main girders, cross beams, and stiffeners, Column base plates and connection brackets, Wind bracing and diaphragm plates, Container corner posts and roof bows, Transmission tower leg members and plates
Application industries: Bridge construction (highway, railway, pedestrian bridges), Architectural and structural steelwork (stadiums, exhibition halls, facades), Transmission line towers and utility structures, Shipping containers, freight wagons, and truck bodies, Offshore and coastal infrastructure (with additional coating if required)
JIS G3114 SMA400CP Weather Resistant Steel Plate Similar / Alternative Materials for Cross‑Reference
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A588 / A588M | Grade A, B, C | Weathering steel with yield 345 MPa; lower strength but similar corrosion resistance |
| EU | EN 10025‑5 | S355J2W, S355K2W | Yield 355 MPa; often used in painted structural applications |
| India | IS 11587 | Fe 490 W | Weathering structural steel, yield ~390-490 MPa range |
| China | GB/T 4171 | Q355GNH | Yield 355 MPa; direct equivalent to S355J2W |
| Russia | GOST 19281 | 10KhSND | Low‑alloy weathering steel, yield ~390 MPa |
Notes:
Additional information:
- For improved atmospheric corrosion resistance, the steel should be exposed to alternating wet and dry conditions. Initial rusting will naturally stabilize into a protective patina (dark brown) over 1–3 years.
- SMA400CP may be supplied with increased impact toughness requirements upon agreement (e.g. 40 J at -20°C).
- Ultrasonic inspection as per JIS G0801 or other standards can be ordered for critical applications.
- When exposed to severe marine environments or industrial pollution, periodic washing is recommended to maintain patina integrity.
- Not recommended for continuously wet or submerged service without protective coatings.
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