Q415NH Weathering Structural Steel Coil
GB/T4171 Q415NH Weather Resistant Steel Coil Data Sheet: Chemistry, Properties, Equivalents & Uses
In-depth technical data for Q415NH weather-resistant steel coil under GB/T4171, including chemical composition, mechanical and thermal properties, global equivalents, and application guidance.
Cutting, bending, welding, punching, cold forming, hot forming, machining
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Q415NH Weathering Structural Steel Coil Introduction
Q415NH is a high-strength weather-resistant structural steel specified in Chinese standard GB/T 4171. It is designed to provide enhanced atmospheric corrosion resistance through the addition of alloying elements such as copper, chromium, and nickel, which promote the formation of a dense, protective oxide patina during outdoor exposure. With a minimum yield strength of 415 MPa, this steel delivers an excellent combination of mechanical performance and long-term durability without the need for protective painting.
- Excellent atmospheric corrosion resistance
- High yield and tensile strength
- Good weldability and cold formability
- Low maintenance requirements over service life
Q415NH Weathering Structural Steel Coil Chemical Composition
The chemical composition as per GB/T 4171-2008 ensures the formation of a self-protective rust layer. Copper, chromium, and nickel are essential for corrosion resistance. Microalloying elements such as niobium, vanadium, or titanium may be added for grain refinement and strength improvement.
| Chemical Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | ≤0.12 | |
| Silicon (Si) | 0.25~0.75 | |
| Manganese (Mn) | ≤1.10 | |
| Phosphorus (P) | ≤0.025 | |
| Sulfur (S) | ≤0.020 | |
| Copper (Cu) | 0.20~0.55 | Corrosion resistance element |
| Chromium (Cr) | 0.50~1.25 | Passivation layer enhancer |
| Nickel (Ni) | 0.12~0.65 | Toughness and corrosion contributor |
| Microalloying (Nb, V, Ti, etc.) | As agreed | Grain refinement, optional addition |
Q415NH Weathering Structural Steel Coil Thermal and Electrical Physical Properties
Physical properties presented below are typical for low-alloy weathering steel and may exhibit slight variations depending on exact chemical composition and heat treatment condition.
| Property | Standard Required Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20°C |
| Elastic Modulus (E) | 206 | GPa | 20°C |
| Shear Modulus (G) | 79 | GPa | 20°C |
| Poisson's Ratio (ν) | 0.3 | — | 20°C |
| Thermal Expansion Coefficient (α) | 12.0 | 10⁻⁶/K | 20–100°C |
| Thermal Expansion Coefficient (α) | 12.8 | 10⁻⁶/K | 20–200°C |
| Thermal Conductivity (λ) | 40 | W/(m·K) | 20°C |
| Specific Heat Capacity | 460 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρ_e) | 0.15 | μΩ·m | 20°C |
Q415NH Weathering Structural Steel Coil Mechanical Properties
Mechanical properties are specified for hot-rolled plates and coils in delivery condition. Tensile tests are performed on transverse specimens; impact tests are conducted on longitudinal Charpy V-notch specimens. Values depend on product thickness as indicated.
| Property | Standard Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥415 | MPa | t ≤ 16 mm |
| Yield Strength (ReH) | ≥405 | MPa | 16 < t ≤ 40 mm |
| Yield Strength (ReH) | ≥395 | MPa | 40 < t ≤ 60 mm |
| Yield Strength (ReH) | ≥385 | MPa | 60 < t ≤ 80 mm |
| Tensile Strength (Rm) | 520~680 | MPa | t ≤ 40 mm |
| Tensile Strength (Rm) | 520~680 | MPa | 40 < t ≤ 80 mm (typical) |
| Elongation after fracture (A) | ≥22 | % | t ≤ 16 mm (L0=5.65√S0) |
| Elongation after fracture (A) | ≥22 | % | 16 < t ≤ 40 mm |
| Elongation after fracture (A) | ≥20 | % | 40 < t ≤ 60 mm |
| Elongation after fracture (A) | ≥20 | % | 60 < t ≤ 80 mm |
| Bending Test (Bend Diameter) | d=2a | — | t ≤ 16 mm, 180° |
| Bending Test (Bend Diameter) | d=3a | — | t > 16 mm, 180° |
| Impact Energy (KV2) | ≥47 | J | Longitudinal, -20°C |
Q415NH Weathering Structural Steel Coil Fully Equivalent Material Standards and Substitutable Grade Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 4171 | Q415NH | Original specification |
| Europe | EN 10025-5 | S355J2W+N | Lower yield strength (355 MPa); equivalent corrosion class, not full substitute |
| USA | ASTM A588 / A588M | Grade B (Grade C) | Min. yield 345 MPa; similar atmospheric corrosion resistance, strength gap |
| Japan | JIS G3125 | SPA-H | Yield 355 MPa; weathering steel for rolling stock, lower strength |
| International | ISO 4952 | Fe 510 D1K1 | Comparable corrosion-resistant grades, but yield typically 355 MPa |
Q415NH Weathering Structural Steel Coil Application Introduction
Q415NH steel is intended for load-bearing applications exposed to the atmosphere, where reduced maintenance and extended service life are important. Its ability to form a stable protective rust layer eliminates the need for paint in many environments. The material can be processed with standard workshop methods.
Product Applications: Shipping containers, Railway wagons and coaches, Highway bridges and overpasses, Building facades and roofing, Transmission towers and poles, Industrial chimneys and ducting, Truck frames and trailers
Processed into products: Corner posts and side panels of containers, Main beams and girders of bridges, Roof and wall cladding systems, Lattice tower legs and bracings, Chassis and structural members of railcars, Exhaust stacks and flue gas ducts, Supporting frames for outdoor equipment
Application industries: Transportation, Construction, Container Manufacturing, Power Transmission, Railway, Architecture
Q415NH Weathering Structural Steel Coil Similar/Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 4171 | Q355GNH | High weathering steel with lower strength (355 MPa), good corrosion resistance |
| China | GB/T 1591 | Q420qE | Bridge structural steel with high strength, limited weather resistance |
| Europe | EN 10025-5 | S355J0WP | Phosphorus-alloyed weathering steel, enhanced corrosion, lower strength |
| USA | ASTM A242 | Type 1 | Weathering steel with min. yield 345 MPa |
| Japan | JIS G3114 | SMA570W | Higher strength weather-resistant steel for bridges (min. 570 MPa), different alloy concept |
Notes:
For optimal atmospheric corrosion resistance, structures should be exposed to cyclic wetting and drying. Avoid continuous immersion in water or contact with permanently damp soil. In coastal or highly corrosive industrial environments, additional painting may be considered. Prequalified welding procedures can be applied, using low-hydrogen electrodes matching the strength level.
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