JIS G3114 SMA490AP Weather Resistant Steel
SMA490AP Weather Resistant Steel – JIS G3114 Hot-Rolled Atmospheric Corrosion Resisting Structural Steel Plate
JIS G3114 SMA490AP is a hot-rolled atmospheric corrosion resisting steel plate for welded structures, offering minimum tensile strength of 490 MPa and enhanced weather resistance through alloying elements like copper, chromium and nickel. Ideal for bridges, building frames and containers.
Hot rolling; suitable for cutting, bending, welding, machining
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JIS G3114 SMA490AP Weather Resistant Steel Introduction
SMA490AP is a structural-quality, hot-rolled weather resistant steel plate defined in JIS G3114. It is designed for welded applications in outdoor environments where protection against atmospheric corrosion is essential. The steel achieves its improved corrosion resistance mainly through the addition of Cu, Cr and Ni, which promote the formation of a dense, adherent oxide layer that inhibits further degradation.
- Classification: Atmospheric corrosion resisting structural steel
- Typical shapes: Plates
- Minimum tensile strength: 490 MPa
- Excellent weldability and formability
SMA490AP belongs to the "A" category, which means it is supplied without any mandatory impact test requirement, making it suitable for ambient temperature applications where notch toughness certification is not critical.
JIS G3114 SMA490AP Weather Resistant Steel Chemical Composition
The chemical composition of SMA490AP is controlled to achieve the required weather resistance and mechanical properties. Copper, chromium and nickel are deliberately added to form a protective patina. All values are according to JIS G3114:2012 for ladle analysis.
| Element | Standard Value (mass %) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.18 | controls strength and hardness |
| Silicon (Si) | 0.15 – 0.65 | deoxidizer, improves strength |
| Manganese (Mn) | ≤ 1.40 | enhances hardenability and strength |
| Phosphorus (P) | ≤ 0.035 | impurity, kept low for ductility |
| Sulfur (S) | ≤ 0.035 | impurity, low for weldability |
| Copper (Cu) | 0.30 – 0.50 | key element for atmospheric corrosion resistance |
| Chromium (Cr) | 0.45 – 0.75 | forms passive layer, improves corrosion resistance |
| Nickel (Ni) | 0.05 – 0.30 | improves toughness and cooperates with Cu |
| Iron (Fe) | Balance | remainder |
JIS G3114 SMA490AP Weather Resistant Steel Physical Properties
Physical properties of SMA490AP are typical for low-alloy structural steels. The values are approximate and can vary slightly with heat treatment and composition. They are provided for thermal and electrical calculations.
- Data based on typical room temperature measurements for similar C-Mn-Cu-Cr-Ni steels.
| Property | Typical Value | Unit | Test Condition / Reference Temperature |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of elasticity (E) | 206 | GPa | 20 °C, longitudinal |
| Shear modulus (G) | 80 | GPa | 20 °C |
| Poisson's ratio (ν) | 0.30 | - | 20 °C |
| Coefficient of thermal expansion (α) | 11.7 | 10⁻⁶/K | 20 – 100 °C |
| Coefficient of thermal expansion (α) | 12.5 | 10⁻⁶/K | 20 – 200 °C |
| Coefficient of thermal expansion (α) | 13.2 | 10⁻⁶/K | 20 – 300 °C |
| Thermal conductivity (λ) | 51 | W/(m·K) | 20 °C |
| Specific heat capacity | 460 | J/(kg·K) | 20 °C |
| Electrical resistivity (ρ_e) | 0.21 | µΩ·m | 20 °C |
JIS G3114 SMA490AP Weather Resistant Steel Mechanical Properties
Mechanical properties of SMA490AP are tested on specimens taken in the rolling direction. Yield strength, tensile strength and elongation vary with plate thickness. The grade does not require impact testing (class A). Bending tests are performed to verify formability.
- All values conform to JIS G3114 for hot-rolled condition.
- No Charpy V-notch impact requirement for SMA490AP.
| Property | Standard Required Value | Unit | Test Condition / Thickness |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 365 | MPa | Thickness ≤ 16 mm, transverse |
| Yield Strength (ReH) | ≥ 355 | MPa | Thickness >16 mm ≤ 40 mm |
| Yield Strength (ReH) | ≥ 335 | MPa | Thickness >40 mm ≤ 75 mm |
| Tensile Strength (Rm) | 490 – 610 | MPa | Thickness ≤ 16 mm |
| Tensile Strength (Rm) | 490 – 610 | MPa | Thickness >16 mm ≤ 40 mm |
| Tensile Strength (Rm) | 490 – 610 | MPa | Thickness >40 mm ≤ 75 mm |
| Elongation (A) | ≥ 15 | % | No. 5 specimen, thickness ≤ 16 mm, gage length 50 mm |
| Elongation (A) | ≥ 17 | % | No. 5 specimen, thickness >16 mm ≤ 40 mm |
| Elongation (A) | ≥ 19 | % | No. 5 specimen, thickness >40 mm ≤ 75 mm |
| Bend test (D = bend diameter, a = thickness) | D = 1.0 a, 180° | - | Thickness ≤ 16 mm |
| Bend test (D = bend diameter, a = thickness) | D = 1.5 a, 180° | - | Thickness >16 mm ≤ 100 mm |
| Charpy impact (KV) | Not required (A category) | - | - |
JIS G3114 SMA490AP Weather Resistant Steel Internationally Equivalent Standards & Substitute Grades
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-5 | S355J0W (1.8959) | Similar weather resistance; 0 °C impact optional; yield 355 MPa |
| China | GB/T 4171 | Q355NH | Weathering structural steel; yield 355 MPa; no mandatory impact |
| USA | ASTM A588 / A588M | Grade A | High-strength low-alloy structural steel; yield 345 MPa |
| International | ISO 4952 | E355DD | Hot-rolled structural steel with improved atmospheric corrosion resistance; similar yield class |
| Russia | GOST 27772 | C345 | Atmospheric corrosion resistant steel; equivalent strength level |
JIS G3114 SMA490AP Weather Resistant Steel Application Introduction
SMA490AP is widely used in structures exposed to the atmosphere without protective painting (bare application) or with minimal coating. It develops a protective rust layer that significantly slows corrosion. The material is easy to weld and form, making it a cost-effective choice for large outdoor steel structures.
Product Applications: Steel bridges (box girders, trusses), Container bodies and frames, Railway wagons and hoppers, Unpainted building frames and facades, Transmission towers, Agricultural and construction equipment parts
Processed into products: Welded built-up H-beams and box columns, Riveted or bolted structural joints, Stiffening plates and gussets, Bogie frames for rail vehicles, Corrugated container panels, Lattice tower angles and flats
Application industries: Bridge construction, Building and civil engineering, Railway rolling stock (wagons, coaches), Container manufacturing, Transmission towers and utility poles, Industrial machinery and storage tanks
JIS G3114 SMA490AP Weather Resistant Steel Similar Materials
| Country / Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3114 | SMA490BW | Class B – requires Charpy impact test at 0 °C, suitable for toughness-demanding applications |
| Japan | JIS G3114 | SMA490CW | Class C – requires Charpy impact test at -10 °C, higher toughness variant |
| Japan | JIS G3114 | SMA570P | Higher strength grade (570 MPa tensile) with similar weather resistance; plates only |
| Europe | EN 10025-5 | S355J0WP | Weather resistant structural steel with P addition for enhanced patina; yield 355 MPa, 0 °C impact |
Notes:
- When used without painting, the surface must be exposed to alternate wet/dry cycles to form a stable patina; initial discharge of rusty water may stain surrounding materials.
- Welding consumables should match the strength and corrosion resistance of the base metal (e.g., AWS E70C-Ni or equivalent low-alloy electrodes).
- Preheating is generally not required for thicknesses up to 50 mm, but recommended according to welding standards for thicker sections.
- The data provided are based on JIS G3114:2012; for exact requirements of a specific project, the latest edition of the standard should be consulted.
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