S420L Hot Rolled Steel Coil
S420L Hot Rolled Steel Coil - High-Strength Low-Alloy Steel for Automotive Chassis and Structural Components
Detailed material data for S420L hot rolled steel coil under GB/T 3273-2005, covering chemical composition, mechanical and physical properties, equivalent grades, and application guidance for automotive structural uses.
Hot rolling, cold forming, press bending, welding, shearing, laser/plasma cutting
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S420L Hot Rolled Steel Coil Introduction
S420L is a hot-rolled high-strength low-alloy (HSLA) steel grade specified in GB/T 3273-2005, primarily designed for automotive chassis and structural applications. It offers an excellent combination of high yield strength, good formability, and adequate toughness, making it suitable for critical load-bearing components such as frame rails, cross members, and reinforcement parts.
The steel is microalloyed with elements like niobium, vanadium, and titanium to achieve grain refinement and precipitation strengthening, resulting in a minimum yield strength of 420 MPa (for thicknesses up to 6 mm). Its superior weldability and cold-forming characteristics allow efficient manufacturing of complex automotive structures. Typical delivery condition is hot-rolled, with optional pickled and oiled surface finish. The material meets stringent requirements for safety-critical vehicle components while enabling weight reduction through high strength-to-weight ratio.
S420L Hot Rolled Steel Coil Chemical Composition
Chemical requirements per GB/T 3273-2005 for S420L heat analysis. The steel is microalloyed with Nb, V, and/or Ti for grain refinement, and aluminum is added as a deoxidizer and grain refiner. The total content of microalloying elements shall not exceed 0.22%.
| Chemical Element | Standard Value (wt%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.12 | Max |
| Silicon (Si) | ≤0.50 | Max |
| Manganese (Mn) | ≤1.60 | Max |
| Phosphorus (P) | ≤0.030 | Max |
| Sulfur (S) | ≤0.025 | Max |
| Aluminum (Al) | ≥0.015 | Min (total Al) |
| Microalloying (Nb+V+Ti) | ≤0.22 | Total max |
S420L Hot Rolled Steel Coil Thermal and Electrical Physical Properties
These physical properties are typical for S420L grade hot-rolled steel and are not mandatory requirements of GB/T 3273-2005. They are provided for design and engineering calculations and may vary slightly depending on exact composition and processing.
| Property | Typical Value | Unit | Test Condition / Remark |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | Room temperature |
| Elastic modulus (E) | 210 | GPa | Tensile modulus, typical for steel |
| Shear modulus (G) | 80 | GPa | Calculated from E and ν (typical) |
| Poisson's ratio (ν) | 0.30 | – | Elastic range |
| Thermal expansion coefficient (α) | 12×10⁻⁶ | K⁻¹ | 20–100 °C (typical for low-carbon steel) |
| Thermal conductivity (λ) | ~50 | W/(m·K) | At 25 °C |
| Specific heat capacity | ~460 | J/(kg·K) | Room temperature |
| Electrical resistivity (ρₑ) | 0.13–0.20×10⁻⁶ | Ω·m | At 20 °C |
S420L Hot Rolled Steel Coil Mechanical Properties
Mechanical properties specified in GB/T 3273-2005 for S420L in hot-rolled condition. Testing is performed on longitudinal specimens taken from the product. Values apply to thickness ranges as indicated. The bending test requires a 180° bend without cracking on the outside surface.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥420 | MPa | Thickness ≤6 mm, longitudinal |
| Yield Strength (ReH) | ≥410 | MPa | Thickness >6–8 mm, longitudinal |
| Yield Strength (ReH) | ≥400 | MPa | Thickness >8–10 mm, longitudinal |
| Tensile Strength (Rm) | 510–650 | MPa | All thicknesses |
| Elongation after fracture (A) | ≥23 | % | Gauge length 50 mm, thickness ≤6 mm |
| Elongation after fracture (A) | ≥22 | % | Thickness >6–8 mm |
| Elongation after fracture (A) | ≥21 | % | Thickness >8–10 mm |
| Bending test | d=0.5a, 180° | – | Bend diameter d, specimen thickness a; no cracks |
| Impact energy (KV2) | ≥24 | J | Longitudinal, -20 °C, Charpy V-notch |
S420L Hot Rolled Steel Coil Directly Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 3273-2005 | S420L | Original specification |
| Europe | EN 10149-2:1996 | S420MC | Thermomechanically rolled; similar strength and chemical concept, but not identical in all thickness ranges |
| International | ISO 6930-2:2004 | FeE420 | Yield strength 420 MPa grade; check exact limits |
| Japan | JFS A1001 (JFS Steel Standards) | A420L | Japanese automotive structural steel; comparable in purpose |
S420L Hot Rolled Steel Coil Application Introduction
S420L steel is extensively used in the automotive and commercial vehicle industries where high strength, good fatigue resistance, and weldability are essential. It is supplied in hot-rolled coil form and subsequently blanked, formed, and welded into structural assemblies. The steel can be processed by common cold-forming methods such as bending, drawing, and stamping. Its fine-grain structure ensures consistent performance in safety-critical applications.
Product Applications: Longitudinal chassis frame rails, Cross members and reinforcements, Suspension brackets and spring hangers, Truck bed and dump body structures, Container chassis and trailer beams
Processed into products: Frame side members (C/L profiles), Engine mounting brackets, Towing hitches and towbar assemblies, Subframe connectors, Axle reinforcement plates
Application industries: Automotive manufacturing (passenger vehicles, trucks, buses), Heavy-duty commercial vehicle (frame and chassis), Trailer and semi-trailer production, Agricultural and construction machinery, Railway wagon structural components
S420L Hot Rolled Steel Coil Equivalent/Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 3273-2015 (revised) | S420L | Updated version of same grade; check minor adjustments |
| China | GB/T 20564.3 (cold rolled) | HC420/780TR | Cold-rolled multiphase steel; higher strength but different forming behavior |
| Europe | EN 10149-2 | S460MC | Higher strength alternative (yield ≥460 MPa); may require adjusted forming |
| USA | ASTM A1011/A1011M | HSLAS-F Grade 420 | HSLA steel with minimum yield 420 MPa; chemistry and impact requirements differ |
Notes:
Surface condition: Hot-rolled scale; optional pickled and oiled (PO) for improved surface quality is available upon agreement.
Dimensional tolerances: Shall comply with the thickness, width, and flatness tolerances specified in GB/T 709 or as agreed between the purchaser and producer.
Weldability: Excellent; suitable for all common arc and resistance welding processes with appropriate procedures.
Corrosion protection: The steel does not possess inherent atmospheric corrosion resistance; automotive components are typically painted or coated after fabrication.
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