B480QZR Hot Rolled Steel Coil
B480QZR Hot Rolled Steel Coil - Q/BQB 310-2009 Technical Data & Equivalent Grades
Comprehensive material data for Baosteel B480QZR hot rolled coil per Q/BQB 310-2009, including chemistry, mechanical and thermal properties, international equivalents, and application guidelines.
Hot rolling, controlled rolling, pickling and oiling available
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B480QZR Hot Rolled Steel Coil Introduction
B480QZR is a hot-rolled high-strength low-alloy (HSLA) steel grade developed by Baosteel under enterprise standard Q/BQB 310-2009. It is designed for demanding automotive structural applications where weight reduction and durability are critical. The steel exhibits a minimum yield strength of 355 MPa and tensile strength in the range 480–620 MPa, combined with excellent formability and weldability.
- Microalloyed with niobium and titanium for grain refinement and precipitation strengthening
- Good fatigue resistance and impact toughness
- Supplied as hot rolled coil with as-rolled or controlled rolled condition
- Widely used for truck frames, wheel rims, and chassis members
B480QZR Hot Rolled Steel Coil Chemical Composition
Typical ladle analysis according to Q/BQB 310-2009 for B480QZR. Microalloying elements Nb and Ti are added to refine grain size and enhance strength. All values are maximum limits unless a range is given. Aluminum is added for deoxidation and grain size control.
| Element | Standard Value (wt.%) | Remarks |
|---|---|---|
| C | ≤0.18 | |
| Si | ≤0.50 | |
| Mn | ≤2.00 | |
| P | ≤0.025 | |
| S | ≤0.015 | |
| Alt (total aluminum) | ≥0.015 | Minimum requirement |
| Nb | ≤0.09 | Microalloying |
| Ti | ≤0.15 | Microalloying |
B480QZR Hot Rolled Steel Coil Thermal and Electrical Physical Properties
These properties are representative for low‑alloy steel grades similar to B480QZR at room temperature unless otherwise noted. Actual values may vary slightly depending on exact chemical composition and microstructure. For design purposes, the values below are generally accepted for HSLA steels.
| Property | Typical Value | Unit | Test Condition / Reference |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Elastic modulus (E) | 210 | GPa | Ambient temperature |
| Shear modulus (G) | 81 | GPa | Ambient temperature |
| Poisson's ratio (ν) | 0.3 | - | Ambient temperature |
| Thermal expansion coefficient (α) | 11.5 × 10⁻⁶ | K⁻¹ | 20–100 °C |
| Thermal conductivity (λ) | 50 | W/(m·K) | At 20 °C |
| Specific heat capacity | 460 | J/(kg·K) | At 20 °C |
| Electrical resistivity (ρ_e) | 0.20 | μΩ·m | At 20 °C |
B480QZR Hot Rolled Steel Coil Mechanical Properties
Transverse test specimens taken from hot rolled coil as per Q/BQB 310-2009. Values meet the specification and are guaranteed for material in the as-rolled condition. Bend test requires 180° bending without cracking. Elongation is measured on a gauge length of 50 mm or proportional to thickness (A50 or A80); the table provides the 50 mm gauge value for common thickness ranges.
| Property | Specified Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield strength (ReH) | ≥355 | MPa | Transverse, as-rolled |
| Tensile strength (Rm) | 480–620 | MPa | Transverse, as-rolled |
| Elongation (A50) | ≥18 | % | Gauge length 50 mm, transverse, thickness ≤3.0 mm |
| Elongation (A50) | ≥19 | % | Gauge length 50 mm, transverse, thickness 3.0–6.0 mm |
| Bend test (180°) | d=1a, no cracks | - | Bend diameter = specimen thickness (a) |
B480QZR Hot Rolled Steel Coil Exact Equivalent Material Standards and Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | Q/BQB 310-2009 | B480QZR | Original grade manufactured by Baosteel |
| International | - | - | No internationally recognised identical grade. Use similar grades after engineering assessment. |
B480QZR Hot Rolled Steel Coil Application Introduction
B480QZR is engineered for parts requiring a combination of high strength, good fatigue resistance, and reliable cold formability. It can be processed by cutting, stamping, bending, and welding with standard methods. Pre-heating is usually not required, but stress relieving after severe forming may be considered. The grade is suitable for both hot‑rolled and pickled‑and‑oiled surface finishes.
Product Applications: Truck chassis frames, Wheel rims and discs, Trailer beams, Vehicle safety reinforcement members, Excavator arms
Processed into products: Longitudinal chassis rails, Cross members, Suspension brackets, Control arm reinforcements, Mounting plates
Application industries: Automotive manufacturing, Commercial vehicles, Agricultural machinery, Construction equipment
B480QZR Hot Rolled Steel Coil Similar Alternative Materials
| Country/Region | Standard | Grade | Remarks / Analysis |
|---|---|---|---|
| Europe | EN 10149-2 | S420MC | Minimum yield 420 MPa, tensile 480–620 MPa. Higher yield strength, good formability. Requires strength adjustment in design. |
| Japan | JIS G3113 | SAPH440 | Tensile strength ≥440 MPa, yield ≥305 MPa. Lower strength; can substitute only after recalculation of thickness. |
| China | GB/T 20887.1 | HR500F | Yield ≥400 MPa, tensile ≥500 MPa. Similar forming grade, slightly higher strength level. |
| USA | SAE J1392 | GR50 | Minimum yield 345 MPa, tensile 450 MPa. Lower tensile strength; use with caution for critical parts. |
Notes:
Welding: B480QZR can be welded using common methods (MIG, MAG, resistance spot welding). The carbon equivalent is controlled to ensure good weldability; preheat is typically not required for thicknesses below 30 mm. Forming: The steel offers excellent bendability; minimum bending radius of 1×thickness for as‑rolled condition is recommended. Corrosion protection: The supplied surface may require painting or coating depending on the application. Similar grade analysis: Among the similar grades, S420MC from EN 10149-2 offers the closest overall mechanical property envelope, though its higher yield strength may allow down‑gauging. SAPH440 is less strong but may be considered for non‑critical parts. GB/T 20887.1 HR500F is a domestic alternative with comparable forming behaviour. A full qualification programme is advised before substitution.
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