SAPH440 Hot Rolled Steel Coil
SAPH440 Hot Rolled Steel Coil: Automotive Structural Grade with Excellent Formability
Detailed technical data for SAPH440 hot-rolled steel coil compliant with JIS G3113-2006 and Q/BQB 310-2009, including chemical composition, mechanical properties, thermal and electrical physical properties, equivalent standards, and application guide.
Cutting, cold forming, bending, stamping, welding, drilling, punching
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SAPH440 Hot Rolled Steel Coil Introduction
SAPH440 is a hot-rolled structural steel primarily used in the automotive industry for parts requiring good formability and high strength. It belongs to the SAPH series under JIS G3113 (Japanese Industrial Standard) and is also specified in the Chinese standard Q/BQB 310. The grade has a minimum tensile strength of 440 MPa, ensuring reliable load-bearing capacity. Its chemical composition is designed to meet mechanical property requirements rather than strict elemental limits, allowing flexibility in production while guaranteeing weldability and moderate corrosion resistance. Typical applications include frames, reinforcements, and chassis components.
SAPH440 Hot Rolled Steel Coil Chemical Composition
The chemical composition of SAPH440 is not strictly prescribed by the standard; instead, it is agreed upon between the manufacturer and purchaser to achieve the required mechanical properties. The values provided are common maximum limits as referenced in typical material certificates and industry practices. These limits ensure good weldability and formability.
| Element | Standard Value (max %) | Remarks |
|---|---|---|
| Carbon (C) | 0.21 | Typical upper limit; may be lower |
| Silicon (Si) | 0.30 | For deoxidation; excess may reduce surface quality |
| Manganese (Mn) | 1.50 | Enhances strength; higher Mn may be used for thicker gauges |
| Phosphorus (P) | 0.030 | Controlled for ductility and welding |
| Sulfur (S) | 0.025 | Improves machinability but kept low for formability |
| Others | Micro-alloying elements (e.g., Nb, Ti, V) may be added to achieve strength | Optional; not mandatory |
SAPH440 Hot Rolled Steel Coil Thermal and Electrical Physical Properties
The following physical properties are typical for low-carbon structural steel and serve as engineering reference values. They are not part of the formal standard but are commonly used in design calculations. Variations may occur depending on actual composition and processing history.
| Property | Standard Requirement Value | Unit | Testing Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | at 20°C |
| Modulus of Elasticity (E) | 200 | GPa | at 20°C |
| Shear Modulus (G) | 80 | GPa | at 20°C |
| Poisson's Ratio (ν) | 0.29 | — | at 20°C |
| Thermal Expansion Coefficient (α) | 11.7 (10⁻⁶/K) | 10⁻⁶/K | 20–100°C |
| Thermal Expansion Coefficient (α) | 12.5 (10⁻⁶/K) | 10⁻⁶/K | 20–200°C |
| Thermal Conductivity (λ) | 51.9 | W/(m·K) | at 20°C |
| Specific Heat Capacity | 486 | J/(kg·K) | at 20°C |
| Electrical Resistivity (ρ_e) | 0.16 | µΩ·m | at 20°C |
SAPH440 Hot Rolled Steel Coil Mechanical Properties
The mechanical properties are determined using test pieces taken in the transverse direction. Values depend on the nominal thickness t. Yield strength refers to the upper yield point (ReH). Elongation is measured with a gauge length of 50 mm (JIS Z 2241 No.5 test piece). The bend test requires no cracks on the outside of the bend after 180° bending to the specified inside radius.
| Property | Standard Requirement Value | Unit | Testing Condition / Thickness |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 305 | MPa | t ≤ 6.0 mm |
| Yield Strength (ReH) | ≥ 295 | MPa | 6.0 mm < t ≤ 14.0 mm |
| Tensile Strength (Rm) | ≥ 440 | MPa | t ≤ 14.0 mm (full thickness range) |
| Elongation (A) | ≥ 29 | % | t ≤ 6.0 mm |
| Elongation (A) | ≥ 26 | % | 6.0 mm < t ≤ 8.0 mm |
| Elongation (A) | ≥ 23 | % | 8.0 mm < t ≤ 14.0 mm |
| Bend Test (180°) | Inside radius = 1.0 × t | — | t ≤ 6.0 mm (no cracks) |
| Bend Test (180°) | Inside radius = 1.5 × t | — | 6.0 mm < t ≤ 14.0 mm (no cracks) |
SAPH440 Hot Rolled Steel Coil Completely Equivalent Material Standards and Substitutable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G3113:2006 | SAPH440 | Original standard, identical grade |
| China | Q/BQB 310-2009 | SAPH440 | Baosteel enterprise standard, fully equivalent to JIS G3113 SAPH440 |
| International | ISO 4997:2007 | HR340 | Mechanical properties closely match; often accepted as functional equivalent |
SAPH440 Hot Rolled Steel Coil Application Introduction
SAPH440 is designed for structural parts requiring both high strength and good deep-drawing or bending capabilities. Its balanced properties make it suitable for mass-produced components in the transportation sector. The steel can be readily welded by common methods (spot, arc, resistance) without significant loss of strength. Parts are typically used in the as-supplied condition without additional heat treatment.
Product Applications: Automobile frames and subframes, Cross members and longitudinal beams, Seat frames and tracks, Wheel discs and rims, Suspension arms and brackets, Reinforcement panels for doors and pillars, Pressed metal components for trailers and caravans
Processed into products: Chassis side rails, Engine mounting brackets, Transmission mounts, Steering knuckle supports, Bumper reinforcement beams, Pedal brackets, Exhaust system hangers, Coupling device plates
Application industries: Automotive and light truck manufacturing, Railway vehicle construction, Agricultural machinery, Construction equipment, General engineering and fabrication
SAPH440 Hot Rolled Steel Coil Similar or Near-Equivalent Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10149-2 | S420MC | Higher min. yield (420 MPa) and tensile (480–620 MPa); suitable for higher strength needs |
| USA | ASTM A1011 / A1011M | HSLAS-F Grade 340 (340y/450t) | Similar tensile strength (min 450 MPa) but different yield and elongation requirements |
| China | GB/T 912 / GB/T 3274 | Q345B | Common structural steel, comparable strength but lower formability than SAPH440 |
| Japan | JIS G3113 | SAPH400 | Lower strength version; may substitute for less demanding applications |
| Japan | JIS G3113 | SAPH370 | Lower strength alternative; only if strength requirements are relaxed |
Notes:
Welding considerations: SAPH440 is easily weldable by all common techniques, but for thicker sections (>8 mm), preheating may be recommended to avoid cold cracking. Surface quality: Pickled and oiled finish is standard for critical exposed applications; optional mill scale can be supplied if specified. Tolerances: Thickness and width tolerances shall be according to JIS G3193 or the corresponding buyer's specification. Certification: Material certificates (e.g., EN 10204 type 3.1) can be provided upon request to guarantee traceability and compliance with the standard.
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