Q550 Steel | High Strength Structural Steel
Q550 Steel | High Strength Structural Steel
Q550 is a high-strength structural steel used in China. “Q” indicates yield strength, and “550” means 550 MPa. Equivalent grades are S550MC and A572 Grade 65. It offers high strength, toughness, and weldability, suitable for heavy machinery, structural parts, bridges, vehicle frames, and high-stress equipment.
We can provide Q550C/D/E products ranging from 6 to 120mm thicknesses, 900～4800 mm width, and 3000～25000 mm length according to the GB/T 1591 standard.
Description
What is Q550 Steel?
Q550 is a high-strength low-alloy structural steel made of around 98% iron with small amounts of carbon, manganese, and other alloying elements. It is typically produced as solid plates or sheets and processed through hot rolling. Q550 offers excellent strength, toughness, and good weldability. It can be further classified into Q550C, Q550D, and Q550E, which differ in their impact resistance at low temperatures. This steel is widely used in heavy machinery, construction, bridges, vehicle frames, and high-stress equipment.Characteristics of Q550 Steel
Q550 steel offers high strength, toughness, good weldability, and excellent wear resistance, making it suitable for heavy machinery, construction, vehicle frames, bridges, and high-stress applications. Q550’s balance of durability and weldability ensures reliable performance across various demanding environments. For projects in extremely low temperatures, alternative grades such as Q690, Q960, or S690QL can be used to meet specific performance needs.Chemical Compositions
| Element | Content (%) |
|---|---|
| Iron, Fe | Balance |
| Carbon, C | 0.10 – 0.20 |
| Manganese, Mn | 1.00 – 1.60 |
| Silicon, Si | ≤ 0.50 |
| Phosphorus, P | ≤ 0.025 |
| Sulfur, S | ≤ 0.015 |
| Chromium, Cr | ≤ 0.30 |
| Nickel, Ni | ≤ 0.70 |
| Molybdenum, Mo | ≤ 0.10 |
| Vanadium, V | ≤ 0.12 |
| Copper, Cu | ≤ 0.40 |
Physical Properties
| Property | Value (Metric) | Value (Imperial) |
|---|---|---|
| Density | 7.85 g/cm³ | 0.283 lb/in³ |
| Melting Point | 1,425 – 1,460 °C | 2,597 – 2,660 °F |
| Boiling Point | ~3,000 °C | ~5,432 °F |
| Thermal Conductivity | 36 – 40 W/(m·K) | 25 – 28 BTU/(hr·ft·°F) |
| Electrical Conductivity | 6.99 MS/m | 6.99 MS/m |
| Specific Heat Capacity | 486 J/(kg·K) | 0.116 BTU/(lb·°F) |
| Thermal Expansion Coefficient | 11 – 13 × 10⁻⁶ /K | 11 – 13 × 10⁻⁶ /°F |
| Electrical Resistivity | 14.3 × 10⁻⁸ Ω·m | 14.3 × 10⁻⁸ Ω·m |
Mechanical Properties
| Property | Value (Metric) | Value (Imperial) |
|---|---|---|
| Tensile Strength | 550 – 620 MPa | 79,770 – 89,923 psi |
| Yield Strength | ≥ 550 MPa | ≥ 79,770 psi |
| Brinell Hardness | 170 – 235 HB | 170 – 235 HB |
| Rockwell Hardness | 83 – 95 HRB | 83 – 95 HRB |
| Vickers Hardness | 170 – 240 HV | 170 – 240 HV |
| Elongation | 16 – 20 % | 16 – 20 % |
| Elastic Modulus | 200 GPa | 29,000 ksi |
Data After QT(Quenching and Tempering) Processing
| Property | Metric | Imperial |
|---|---|---|
| Tensile Strength | 700 – 850 MPa | 101,500 – 123,000 psi |
| Yield Strength | ≥ 620 MPa | ≥ 89,923 psi |
| Brinell Hardness | 250 – 300 HB | 250 – 300 HB |
| Rockwell Hardness | 95 – 100 HRB / 35 – 40 HRC | 95 – 100 HRB / 35 – 40 HRC |
| Vickers Hardness | 270 – 330 HV | 270 – 330 HV |
| Elongation | 10 – 14% | 10 – 14% |
| Elastic Modulus | 200 GPa | 29,000 ksi |
Industries & Applications
| Industries | Products |
|---|---|
| Construction | Bridges, Beams, Columns, Trusses, Towers |
| Mining | Dump Trucks, Conveyor Systems, Crushers, Buckets, Drilling Equipment |
| Heavy Machinery | Excavators, Cranes, Bulldozers, Loaders, Drilling Rigs |
| Shipbuilding | Hulls, Decks, Containers, Support Frames, Ramps |
| Aerospace | Landing Gears, Structural Panels, Cargo Hold Frames, Ladders, Supports |
| Railways | Rail Tracks, Train Bogies, Couplers, Brake Components, Switchgear Frames |
| Automotive | Truck Frames, Chassis, Axles, Trailers, Reinforcement Bars |
| Energy | Wind Turbine Towers, Transmission Poles, Oil Rig Structures, Solar Frames, Offshore Platforms |
Machining
Q550 Steel Surface Treatments
- Shot Blasting: Removes rust, scale, and surface contaminants, improving adhesion for coatings.
- Galvanizing: Coats the steel with a layer of zinc to prevent corrosion and enhance durability.
- Powder Coating: Provides a smooth, durable, and decorative finish with excellent corrosion resistance.
- Painting: Offers corrosion protection and aesthetic enhancement with customizable colors.
- Anodizing: Improves surface hardness and corrosion resistance, often used for specialized finishes.
- Plating (Nickel, Chromium): Enhances wear resistance, corrosion protection, and surface appearance.
- Laser Engraving or Etching: Creates permanent markings or designs for identification and branding.
Disclaimer
The above heat treatment instructions and surface finish processing methods for Q550 steel are provided for informational purposes only. Actual results may vary based on specific conditions and equipment used. Testing is recommended, and a metallurgical expert or material supplier should be consulted to ensure the processes are suitable for your specific application. The user assumes all risks and liability for the use of this information.
Our Service
SteelPRO Group – manufacturer and solution provider for special steel, offering multi-industry application solutions and customised services, 100% quality free, accompanying customers in their growth!
Our Quality Control
- Roundness
- Tolerance
- Microstructure
- Non-Destructive Testing
- Destructive Testing
- Process Control
Service Integration Processing
- Welding
- Metal Fabrication
- CNC Machining
- Lathe
- Forming
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