1. Key Properties:
High Strength: SAE 4135 QT is a quenched and tempered alloy steel that offers enhanced tensile and yield strength compared to standard SAE 4135, making it suitable for demanding, high-pressure applications.
Improved Toughness: The quenching and tempering processes increase toughness, making it highly resistant to shock loads and impacts.
Enhanced Hardness: The heat treatment process improves the hardness of the steel, making it more resistant to wear and abrasion.
Weldability: SAE 4135 QT has good weldability, though preheating may be required for certain heavy welds to reduce the risk of cracking.
Corrosion Resistance: Offers moderate resistance to corrosion, suitable for industrial applications where exposure to harsh environments is expected.
Heat Treatable: It is still heat-treatable, allowing for further customization of mechanical properties to suit specific requirements.
2. Applications/Industries:
Oil & Gas: Commonly used for high-pressure pipelines, drill pipes, and other oilfield equipment that need to withstand extreme stresses and harsh conditions.
Aerospace: Employed in critical aerospace components such as landing gear and other parts that require both high strength and toughness.
Automotive: Suitable for automotive components subjected to high stress, such as axles, shafts, and gears.
Heavy Machinery: Ideal for parts that must endure significant loads and harsh working conditions, including gears, crankshafts, and rods.
Hydraulic Systems: Used in hydraulic cylinders, pistons, and rods where high strength, impact resistance, and wear resistance are critical.
3. Certifications/Standards:
SAE J403: SAE 4135 QT conforms to the SAE J403 standard for alloy steels, ensuring it meets specific chemical and mechanical properties.
ASTM A519: This standard applies to seamless carbon and alloy steel mechanical tubing, which is applicable to SAE 4135 QT pipes.
ISO 9001: Quality management system certification.
4. Chemical Composition:
Carbon (C): 0.30% – 0.35%
Manganese (Mn): 0.60% – 0.90%
Chromium (Cr): 0.80% – 1.10%
Molybdenum (Mo): 0.15% – 0.25%
Silicon (Si): 0.20% max
Phosphorus (P): 0.035% max
Sulfur (S): 0.035% max
Iron (Fe): Balance
5. Technical Specifications:
Yield Strength:
SAE 4135 QT: 500 MPa (minimum)
Tensile Strength:
SAE 4135 QT: 685–850 MPa
Hardness:
SAE 4135 QT: Approximately 200–285 HB (Brinell hardness)