In the world of automotive manufacturing, materials used for safety components like door locks must meet strict requirements for strength, precision, and durability. Among the many alloy steels available, SCM435 polished bars have become one of the most trusted materials for producing automotive door lock buckles and other high-strength structural parts. This article explores the key properties, advantages, and applications of SCM435 alloy steel in the automotive field.
Chemical Composition of SCM435
| Element | Content (%) | Function |
|---|---|---|
| Carbon (C) | 0.33–0.38 | Increases hardness and strength |
| Silicon (Si) | 0.15–0.35 | Enhances elasticity and heat resistance |
| Manganese (Mn) | 0.60–0.85 | Improves toughness and machinability |
| Chromium (Cr) | 0.90–1.20 | Enhances wear resistance and surface hardness |
| Molybdenum (Mo) | 0.15–0.30 | Boosts fatigue strength and heat resistance |
| Phosphorus (P) | ≤ 0.03 | Kept low to ensure purity and toughness |
| Sulfur (S) | ≤ 0.03 | Enhances machinability under control |
This precise chemical balance allows SCM435 to achieve a perfect combination of tensile strength, ductility, and machinability, making it highly suitable for precision machining such as turning, drilling, and polishing.
Mechanical Properties of SCM435
| Property | Value (After Quenching & Tempering) |
|---|---|
| Tensile Strength (MPa) | 930–1080 |
| Yield Strength (MPa) | 785–930 |
| Hardness (HRC) | 28–35 |
| Elongation (%) | 12–15 |
| Impact Toughness (J/cm²) | ≥ 60 |
After heat treatment, SCM435 alloy steel exhibits high strength and stable hardness, capable of withstanding significant stress and repeated impact without cracking or deformation — an essential trait for automotive locking mechanisms.
Why SCM435 Is Ideal for Automotive Door Lock Components
1. Exceptional Strength and Toughness
Door lock buckles experience frequent mechanical stress during vehicle operation. SCM435’s high chromium-molybdenum content ensures excellent tensile and fatigue strength, keeping the lock structure stable over thousands of cycles.
2. Excellent Surface Finish and Plating Compatibility
SCM435 polished bars feature smooth surfaces and fine grain structures, making them ideal for electroplating. A uniform surface helps achieve strong bonding during coating or surface treatment, ensuring both corrosion resistance and appearance quality.
3. Reliable Dimensional Accuracy
With precision drawing and polishing processes, the tolerance of SCM435 polished bars can reach ±0.01 mm, and straightness deviation is controlled within 0.02 mm. This high precision ensures perfect fitting during assembly and reduces secondary machining.
4. High Fatigue and Impact Resistance
Automotive locks face vibration and impact from repeated opening and closing. SCM435’s tempered microstructure resists microcracks, maintaining structural integrity and prolonging service life.
Typical Applications of SCM435 Alloy Steel
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Automotive door lock buckles and locking pins
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Transmission and steering shafts
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Connecting rods and high-load bolts
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Precision mechanical linkages
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Industrial fasteners and structural parts
These applications benefit from SCM435’s combination of mechanical strength, stability, and machinability, making it an ideal choice for both OEMs and precision parts manufacturers.
Why Choose Tongyi Metal’s SCM435 Polished Bars
At Tongyi Metal, every SCM435 polished bar undergoes strict heat treatment, fine grinding, and dimensional testing. Our product advantages include:
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Stable hardness range (HRC 28–35) after quenching and tempering
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Tight dimensional tolerance (±0.01 mm) for precision assembly
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Smooth surface finish (Ra ≤ 0.4) for direct use in CNC machining
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Excellent machinability suitable for centerless grinding, polishing, and threading
These bars are widely used by automotive manufacturers and precision machining factories that prioritize durability, stability, and cost efficiency.
SCM435 alloy steel polished bars have proven to be one of the best material solutions for automotive door lock components, offering high strength, fatigue resistance, and superior surface finish. Their balanced properties make them suitable for both mass production and high-precision machining.
Choosing Tongyi Metal’s SCM435 polished bars means investing in stable quality, precision performance, and reliable supply—ensuring your automotive parts deliver both safety and long-lasting durability.
