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Technical Specifications
Product Overview
Metallurgical Characteristics
GB Q420 steel features a fine-grained ferrite-pearlite microstructure achieved through controlled rolling and accelerated cooling processes. The addition of microalloying elements such as vanadium, niobium, and titanium provides grain refinement and precipitation strengthening, resulting in enhanced mechanical properties and improved toughness.
Heat Treatment
GB Q420 steel is typically supplied in the hot-rolled condition with controlled cooling. Normalizing treatment at 900-950°C followed by air cooling can be applied to refine grain structure and improve mechanical properties. Stress relief annealing at 600-650°C may be performed after welding or forming operations.
Manufacturing Process
MetalZenith produces GB Q420 steel using electric arc furnace steelmaking followed by ladle refining for precise chemical composition control. The steel undergoes controlled rolling with specific temperature and reduction schedules, followed by accelerated cooling to achieve optimal microstructure and mechanical properties. Continuous casting ensures excellent internal quality and surface finish.
Weldability and Fabrication
GB Q420 steel exhibits excellent weldability with low carbon equivalent values. Common welding processes including SMAW, GMAW, FCAW, and SAW can be successfully employed. Preheating may be required for thick sections or high restraint conditions. The steel demonstrates good formability and machinability characteristics.
Quality Standards
All GB Q420 steel products comply with Chinese national standard GB/T 1591 and undergo comprehensive testing including chemical analysis, tensile testing, impact testing, and ultrasonic inspection. MetalZenith maintains strict quality control procedures with ISO 9001:2015 certification and provides complete mill test certificates with full material traceability.
🧪 Chemical Composition
Element | Composition (%) |
---|---|
Carbon (C) | ≤ 0.20 |
Manganese (Mn) | 1.00-1.70 |
Silicon (Si) | 0.15-0.55 |
Phosphorus (P) | ≤ 0.030 |
Sulfur (S) | ≤ 0.025 |
Chromium (Cr) | ≤ 0.30 |
Nickel (Ni) | ≤ 0.50 |
Molybdenum (Mo) | ≤ 0.20 |
Vanadium (V) | 0.02-0.15 |
Niobium (Nb) | 0.015-0.060 |
Titanium (Ti) | 0.02-0.20 |
Aluminum (Al) | ≥ 0.015 |
⚙️ Mechanical Properties
Property | Value |
---|---|
Yield Strength (ReL) | ≥ 420 MPa |
Tensile Strength (Rm) | 520-680 MPa |
Elongation (A) | ≥ 18% |
Impact Energy (KV2) at 20°C | ≥ 34 J |
Impact Energy (KV2) at 0°C | ≥ 34 J |
Impact Energy (KV2) at -20°C | ≥ 27 J |
Brinell Hardness (HB) | 170-230 |
Young's Modulus | 210 GPa |
Poisson's Ratio | 0.30 |
Fatigue Limit (107 cycles) | 210 MPa |
🔬 Physical Properties
Property | Value |
---|---|
Density | 7.85 g/cm³ |
Melting Point | 1510°C |
Thermal Conductivity (20°C) | 54 W/m·K |
Thermal Expansion Coefficient (20-100°C) | 12×10-6/K |
Specific Heat Capacity | 500 J/kg·K |
Electrical Resistivity (20°C) | 0.16 µΩ·m |
Magnetic Permeability | Ferromagnetic |
Curie Temperature | 770°C |
Thermal Diffusivity | 13.8 mm²/s |
📏 Product Specifications
Specification | Available Options |
---|---|
Product Forms | Plates, Sheets, Bars, Beams, Channels, Angles |
Plate Thickness | 6-150 mm |
Sheet Thickness | 0.5-6 mm |
Bar Diameter | 10-300 mm |
Width Range | 1000-4000 mm |
Length Range | 2000-18000 mm |
Standards | GB/T 1591, GB/T 3274, GB/T 709 |
Surface Finish | Hot Rolled, Normalized, Shot Blasted, Pickled |
Dimensional Tolerance | ±0.5-2.0 mm (depending on dimensions) |
Edge Condition | Mill Edge, Slit Edge, Cut Edge |
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Our Advantages in Processing GB Q420

Advanced Thermomechanical Processing
MetalZenith employs cutting-edge controlled rolling and accelerated cooling technologies to optimize the microstructure of GB Q420 steel, achieving superior mechanical properties and enhanced toughness while maintaining excellent weldability and formability characteristics.
Comprehensive Quality Control System
Our integrated quality management system features real-time chemical composition monitoring, automated mechanical testing, and advanced non-destructive inspection methods including ultrasonic testing and magnetic particle inspection to ensure every product meets or exceeds GB/T 1591 specifications.


Flexible Manufacturing & Global Supply
MetalZenith offers extensive customization capabilities including various product forms, dimensions, and surface treatments. Our global distribution network and strategic inventory management ensure reliable supply chain performance with competitive lead times for projects worldwide.
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