QT SAE 4140 Forged Steel
PRODUCT DESCRIPTION
QT SAE 4140 forged steel offers high strength, toughness, and wear resistance, ideal for heavy-duty components in automotive, aerospace, and machinery industries.PRODUCT TYPES
- Hot Rolling and Forged QT Steels between 30mm and 610 mm.
QT SAE 4140 Forged Steel: Overview
QT SAE 4140 is a high-strength alloy steel commonly used in various industrial applications, especially in heavy-duty and high-stress environments. Known for its excellent combination of strength, toughness, and wear resistance, 4140 is typically used in the manufacturing of forged components like gears, shafts, and crankshafts. This steel is heat-treated (quenched and tempered) to improve its mechanical properties, making it suitable for demanding applications in industries such as automotive, aerospace, and machinery manufacturing.
It provides high tensile strength, good fatigue resistance, and excellent machinability. QT SAE 4140 offers versatility in its applications, ranging from industrial machinery parts to structural components, making it ideal for critical applications where both strength and durability are essential.
Chemical Composition (in %)
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.38 – 0.43 |
| Silicon (Si) | 0.20 – 0.35 |
| Manganese (Mn) | 0.60 – 0.90 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.035 max |
| Chromium (Cr) | 0.80 – 1.10 |
| Molybdenum (Mo) | 0.15 – 0.25 |
| Nickel (Ni) | 0.25 max |
Physical Properties
- Density: 7.85 g/cm³ (or 7850 kg/m³)
- Tensile Strength (Rm): 850–1000 MPa
- Yield Strength (Rp0.2): 655 MPa (min)
- Elongation (A): ≥ 20% (for thickness up to 20 mm)
- Hardness (HB): 255–330 (depending on heat treatment)
Machinability
QT SAE 4140 steel is known for its good machinability after heat treatment. It can be easily cut, turned, drilled, and milled with the proper tools. While it can be harder to machine in its quenched state, it is easier to process when tempered. High-speed steel (HSS) or carbide tools should be used for machining operations.
Weldability
QT SAE 4140 has good weldability but requires proper procedures due to its alloy content. Preheating and post-weld heat treatment (PWHT) are often required, especially for thicker sections, to prevent cracking. Low-hydrogen electrodes and proper welding techniques are recommended for best results.
Applications
QT SAE 4140 is used in critical and high-performance applications that require both strength and toughness. It is commonly found in:
- Automotive Industry: Crankshafts, gears, axle shafts
- Aerospace Industry: Landing gear components, turbine shafts
- Machine Manufacturing: Heavy-duty industrial machinery parts
- Oil and Gas: Downhole tools, drilling equipment
Industries Using QT SAE 4140 Forged Steel
- Automotive: High-strength components such as gears, shafts, and crankshafts.
- Aerospace: Aircraft landing gear, turbine components.
- Heavy Equipment Manufacturing: Gears and shafts for heavy-duty machinery.
- Oil & Gas: Equipment for high-stress applications like drilling and downhole tools.
Key Advantages of QT SAE 4140
- High Strength and Toughness: Ideal for high-stress and high-performance applications.
- Good Fatigue Resistance: Suitable for dynamic loading conditions.
- Excellent Machinability: Can be easily processed with the right tools.
- Versatility: Used in various industries, including automotive, aerospace, and heavy equipment manufacturing.