Q295NH Atmospheric Corrosion Resistant Weathering Steel Plate

GB/T 4171 | Patina-Forming Steel with 295 MPa Minimum Yield Strength

What is Q295NH Weathering Steel?

Q295NH is a high-strength Chinese-grade structural weathering steel standardized under GB/T 4171. The "NH" stands for "Nai Hou" (耐候), directly translating to "weather resistance". As a medium-strength weathering steel, it delivers balanced mechanical performance while forming a dense, stable, and adherent protective patina layer in natural atmospheric environments. This self-protecting characteristic provides 2 to 8 times the corrosion resistance of conventional carbon steel, making it ideal for outdoor structures requiring reliable strength and durability.

Decoding the Grade: Q295NH

The naming follows the Chinese steel grade system, where each part reveals key performance characteristics:

Q Yield Strength Designator — Structural steel where "Q" stands for "Qu" (屈), representing Yield Point.
295 Minimum Yield Strength — Guarantees a minimum yield strength of 295 MPa (for thickness ≤16mm).
NH Weathering Quality Grade — "Nai Hou" (耐候) indicates atmospheric corrosion resistance with alloying elements (Cu, Cr, Ni) enabling patina formation.

Domestic Grades Comparison

Q235NH

Yield Strength: ≥235 MPa
Strength Level: Low Strength
Application: Light-load structures
Key Alloy Elements (GB/T 4171)
Cu: 0.25-0.55% | Cr: 0.40-0.80% | Ni: ≤0.65%

Q295NH

Yield Strength: ≥295 MPa
Strength Level: Medium Strength
Application: Medium-load structures
Key Alloy Elements (GB/T 4171)
Cu: 0.25-0.55% | Cr: 0.40-0.80% | Ni: ≤0.65%

Q355NH

Yield Strength: ≥355 MPa
Strength Level: High Strength
Application: Heavy-duty infrastructure
Key Alloy Elements (GB/T 4171)
Cu: 0.25-0.55% | Cr: 0.40-0.80% | Ni: ≤0.65%

Core Characteristics:
✔ All three grades share identical weathering alloy composition (Cu, Cr, Ni) for excellent corrosion resistance.
✔ Strength increases with grade number, while workability and cost efficiency decrease slightly.
✔ Q295NH provides the optimal balance for most general engineering projects.

Chemical Composition (GB/T 4171)

Grade C Si Mn P S Cu Cr Ni Others
Q295NH ≤0.15 0.10-0.50 0.30-1.00 ≤0.030 ≤0.030 0.25-0.55 0.40-0.80 ≤0.65 Nb,V,Ti optional
Microalloying: Nb 0.015-0.060%, V 0.02-0.12%, Ti 0.02-0.10%, Alt ≥0.020%. V+Nb+Ti ≤0.22%.

Mechanical & Processing Properties

Thickness (mm) Yield Strength (MPa) ≥ Tensile Strength (MPa) Elongation (%) ≥ 180° Bending
≤16 295 430-560 24 a
>16~40 285 24 2a
>40~60 275 23 3a
>60 255 22 3a

Note: a = specimen thickness; Bending test: mandrel diameter = a/2a/3a

Available Supply Range

Thickness Range

  • Hot-rolled plates: 3mm - 250mm
  • Sheets / Coils: 1.5mm - 20mm
  • Custom thickness: Available upon request

Width & Length

  • Width: 900mm - 4000mm
  • Length: 2000mm - 18000mm
  • Custom sizes: Cut-to-length available

Product Forms

  • Steel Plates (hot-rolled, normalized)
  • Steel Sheets & Coils
  • Sections: H-beams, I-beams, Channels, Angles
  • Flat bars & Round bars

Surface & Edge Options

  • As-rolled surface / Shot blasted
  • Primer coated (optional)
  • Mill edge / Trimmed edge
  • Beveled edge for welding
Stock availability: Regular sizes in stock for quick delivery | Mill order: Custom sizes available with 20-35 days lead time

Custom Dimensions & Processing

Custom Sizes

Non-standard dimensions

Laser/Plasma Cutting

CNC precision cutting

Edge Beveling

Single/double bevel

Drilling & Punching

Custom hole patterns

Bending & Forming

Plate rolling, profiling

Surface Treatment

Shot blasting, priming

Engineering Support: Free CAD assistance, nesting optimization, technical consultation

Advantages & Typical Applications

Key Advantages

  • Medium strength design, wider application than Q235NH
  • Better cost efficiency compared with Q355NH
  • 2-8x corrosion resistance vs carbon steel
  • Excellent weldability and formability
  • No painting required, reduces lifecycle costs

Typical Applications

  • Bridges & medium-load steel structures
  • Containers, vehicles and engineering machinery
  • Transmission towers & infrastructure
  • Architectural structures & outdoor facilities

Frequently Asked Questions (FAQ)

1. What does "NH" mean in Q295NH?
2. What is the difference between Q295NH and Q235NH?
3. What is the difference between Q295NH and Q355NH?
4. Does Q295NH form a protective patina?
5. Is Q295NH suitable for structural use?

Supply Information

Available Forms

  • Plates & Sheets
  • Hot-rolled Coils
  • Sections (H-beams, Channels, Angles)
  • Bars

Delivery Condition

  • Hot-rolled: As-rolled, controlled-rolled, or normalized
  • Cold-rolled: Annealed condition

MOQ & Lead Time

  • Standard MOQ: 5 tons
  • Stock items: 30-35 days
  • Custom production: 35-45 days

Start Your Q295NH Project

Emails go directly to customize@cehesteel.com — reply within 12 hours.