SPFH590 Hot Rolled Steel Coil
SPFH590 Hot Rolled Steel Coil - High Strength Formable Steel for Automotive
Comprehensive data on SPFH590 hot rolled steel coil per Baosteel Q/BQB 310-2009, covering chemical composition, mechanical and thermal properties, equivalent grades, and application guidance.
Cold forming, stamping, bending, drawing, welding
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
SPFH590 Hot Rolled Steel Coil Introduction
SPFH590 is a high-strength hot-rolled steel coil developed for automotive structural components that demand a balance of strength and formability. Conforming to Baosteel standard Q/BQB 310-2009, this grade guarantees a minimum tensile strength of 590 MPa while retaining adequate elongation for cold forming operations such as stamping, bending, and drawing. The chemistry is designed with low carbon and controlled microalloying to refine grain size and enhance mechanical properties. The steel is supplied in a pickled and oiled condition, offering a clean surface suitable for subsequent welding, painting, and coating processes. Its typical applications include chassis parts, reinforcements, and wheels, where weight reduction and high fatigue resistance are essential.
SPFH590 Hot Rolled Steel Coil Chemical Composition
The chemical composition for SPFH590 according to Q/BQB 310-2009 (heat analysis). The steel is microalloyed with elements such as Nb, Ti, or V (not mandatory but commonly used) to achieve grain refinement and precipitation strengthening. Total aluminum is controlled for deoxidation. Carbon equivalent and inclusion control ensure good weldability and formability.
| Chemical Element | Standard Value | Remarks |
|---|---|---|
| C | ≤ 0.15 | Low carbon for weldability |
| Si | ≤ 0.50 | Silicon as deoxidizer and strengthener |
| Mn | ≤ 2.00 | Manganese for solid solution strengthening |
| P | ≤ 0.030 | Phosphorus limited for ductility |
| S | ≤ 0.025 | Sulfur control improves formability |
| Alt (Al total) | ≥ 0.015 | Aluminum for deoxidation and grain refinement |
SPFH590 Hot Rolled Steel Coil Thermal and Electrical Physical Properties
The following values are typical for high-strength low-alloy hot-rolled steel with a ferritic microstructure, similar to SPFH590. Actual properties may vary slightly with precise composition and processing. These data are useful for design calculations involving thermal loads, springback prediction, and welding simulations.
| Property | Typical Value | Unit | Test Conditions |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | Room temperature |
| Modulus of Elasticity (E) | 210 | GPa | Room temperature |
| Shear Modulus (G) | 81 | GPa | Calculated from E and Poisson's ratio |
| Poisson's Ratio (ν) | 0.30 | - | Room temperature |
| Mean Coefficient of Thermal Expansion (α) | 12.0 (20–100 °C) / 12.6 (20–200 °C) / 13.3 (20–400 °C) | 10⁻⁶/K | Mean linear expansion |
| Thermal Conductivity (λ) | 50 (at 20 °C) / 43 (at 200 °C) / 36 (at 400 °C) | W/(m·K) | Typical for low carbon steel |
| Specific Heat Capacity | 460 (at 20 °C) / 500 (at 200 °C) / 580 (at 400 °C) | J/(kg·K) | Approximate values |
| Electrical Resistivity (ρ_e) | 0.22 | 10⁻⁶ Ω·m | At 20 °C |
SPFH590 Hot Rolled Steel Coil Mechanical Properties
Mechanical properties are specified in Q/BQB 310-2009 for delivery condition. Tests are performed on transverse specimens taken from the coil. Values depend on thickness; the table presents the minimum requirements for common thickness ranges. The bend test ensures adequate cold formability without cracking.
| Property | Required Value | Unit | Test Conditions |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 355 | MPa | Upper yield strength or 0.2% proof stress, transverse direction, all thicknesses |
| Tensile Strength (Rm) | ≥ 590 | MPa | Transverse direction, all thicknesses |
| Elongation (A80mm) | ≥ 20 (for t ≤ 3.0 mm) / ≥ 22 (for t > 3.0 mm) | % | Gauge length 80 mm, transverse direction; thickness 't' in mm |
| Bend Test (180°) | d=0.5a (t ≤ 3.0 mm); d=1.0a (t > 3.0 mm) | - | Bend over a mandrel diameter (d) as multiple of specimen thickness (a); no cracks allowed |
SPFH590 Hot Rolled Steel Coil Directly Equivalent Material Standards and Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G 3135 | SPFH590 | Identical chemical and mechanical requirements; widely used in Japanese automotive industry. |
SPFH590 Hot Rolled Steel Coil Application Introduction
SPFH590 is engineered for applications where high static and dynamic strength, combined with good cold formability, are needed. Its fine-grained microstructure provides excellent fatigue performance and weldability, making it a preferred material in mass-reduced vehicle designs. The steel can be formed using conventional press shop equipment, and the pickled surface accepts various coatings (e-coat, powder, etc.) without additional preparation.
Product Applications: Passenger car body-in-white components, Chassis frames and sub-frames, Wheel rims and spoke discs, Cross members and longitudinal beams, Bumper reinforcements and impact beams, Suspension arms and spring seats, Tubular structural parts
Processed into products: Front and rear cross members, Engine cradle (sub-frame), Lower and upper control arms, Seat frame rails, Bumper back beams, Wheelhouse panels, Reinforcement brackets for A/B pillars, Chassis stiffeners
Application industries: Automotive manufacturing, Commercial vehicle and trailer construction, Agricultural and construction machinery, Material handling equipment, Lightweight steel structures
SPFH590 Hot Rolled Steel Coil Similar/Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10149-2 | S500MC | Higher yield strength (≥500 MPa) but similar tensile strength; may require process adjustments for forming. |
| Europe | EN 10149-2 | S420MC | Lower yield strength (≥420 MPa) with tensile up to 620 MPa; suitable for less demanding applications where strength can be traded for ductility. |
| Japan | JIS G 3134 | SPFH540 | Lower strength grade (tensile ≥ 540 MPa) with better formability, can be used if strength requirements permit. |
| China | GB/T 20887.1 | HR550F | High formability hot-rolled steel with tensile ≥550 MPa; offers comparable forming characteristics, subject to qualification tests. |
Notes:
The steel is normally supplied in a pickled and oiled condition (SPFH590 PO), providing a clean surface free of scale. For thicknesses above 6.0 mm, mechanical property declarations are subject to agreement between the supplier and the purchaser. This grade can be resistance spot welded and arc welded with standard parameters, and laser welding is also feasible with appropriate shielding gas. Hot-dip galvanizing is possible, but the final mechanical properties may shift due to the thermal cycle; furnace brazing or heat treatments should be evaluated on a case-by-case basis.
- Share
