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Alloy Steel CNC Machining Solutions from China Suppliers - High-Quality Parts by Expert Factory
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Common Alloy Steel Material Library
We maintain a complete inventory of high-quality alloy steels, including structural steel, carburizing steel, quenched & tempered steel, and tool steel, to meet the stringent requirements of diverse applications.
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Low-Carbon Steel / Free-Machining Steel
1018 Steel
General-Purpose Low-Carbon Steel
Excellent weldability and machinability. Suitable for surface carburizing/quenching to achieve a hard, wear-resistant surface with a tough core. Commonly used for shafts, pins, gears, etc.
1215 Steel
High-Sulfur Free-Machining Steel
Superior chip-breaking performance, enabling high surface finish quality and faster machining speeds. Ideal for mass production of standard parts such as bolts, nuts, and bushings.
2
Chromium-Molybdenum Alloy Structural Steel (High-Strength)
4130 Steel
Aerospace & Racing Grade
Excellent strength, toughness, and weldability. A classic material for aerospace structural tubing (e.g., aircraft engine mounts) and high-performance racing chassis, typically normalized or quenched & tempered.
4140 Steel
Most Widely Used Cr-Mo Steel
High strength, good wear resistance, and impact toughness. Achieves different strength levels through quenching & tempering. Widely used for gears, shafts, couplings, and die sets.
4140 PH Steel
Pre-Hardened Convenience
⭐ Pre-Hardened
Supplied pre-quenched & tempered (typically HRC 28–32), offering stable mechanical properties and machinability. Can be machined directly without post-heat treatment, avoiding deformation risks. Commonly used for dies and mechanical components.
4340 Steel
Heavy-Duty Critical Components
Exceptional strength, toughness, and fatigue resistance, especially suitable for large-section critical load-bearing components. The preferred material for aircraft landing gear, heavy-duty drive shafts, and high-performance racing crankshafts.
3
Tool Steel (High Wear Resistance / High Hardness)
A2 Tool Steel
Air-Hardening Cold-Work Steel
Good wear resistance, moderate toughness, and minimal heat treatment deformation. Widely used for precision stamping dies, shear blades, and gauges.
O1 Tool Steel
Oil-Hardening General-Purpose Steel
Renowned for excellent edge retention, machinability, and simple heat treatment. Commonly used for hand tools, gauges, cutting tools, and low-life molds.
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Frequently Asked Questions
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What is the difference between 4140 Steel and 4140 PH Steel?
4140 Steel is supplied in an annealed or normalized condition and requires heat treatment after machining to reach the desired hardness. 4140 PH (Pre-Hardened) Steel is already quenched and tempered to approximately HRC 28–32 before delivery, allowing it to be machined directly without further heat treatment, which reduces the risk of dimensional distortion.
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Which alloy steel is best suited for aerospace structural applications?
4130 Steel and 4340 Steel are both widely used in aerospace. 4130 is preferred for structural tubing and lightweight frames due to its excellent weldability. 4340 is chosen for highly stressed, large-section components such as aircraft landing gear, where superior strength, toughness, and fatigue resistance are critical.
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What makes 1215 Steel ideal for high-volume production runs?
1215 Steel contains elevated sulfur content, which acts as a built-in lubricant during cutting. This results in excellent chip-breaking characteristics, reduced tool wear, and the ability to run at higher machining speeds — making it highly cost-effective for mass production of small standard parts like bolts, nuts, and bushings.
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How do A2 and O1 Tool Steels differ in terms of heat treatment and application?
A2 Tool Steel is air-hardened, which means it cools in still air after austenitizing, resulting in minimal distortion — making it ideal for precision dies and gauges. O1 Tool Steel is oil-hardened and offers superior machinability and edge retention, making it a popular choice for cutting tools, hand tools, and general-purpose molds where tight dimensional tolerances are less critical.
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Can 1018 Steel be hardened to improve surface wear resistance?
Yes. Although 1018 is a low-carbon steel with limited through-hardening capability, it responds very well to case hardening processes such as carburizing or carbonitriding. These processes enrich the surface layer with carbon, allowing it to be quenched to a hard, wear-resistant case while retaining a tough, ductile core — ideal for components like shafts, pins, and gears.
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Why is 4340 Steel preferred over 4140 Steel for heavy-duty, large-section components?
4340 Steel contains nickel in addition to chromium and molybdenum, which significantly improves hardenability, toughness, and fatigue strength — especially in thick cross-sections where 4140 may not fully harden throughout. This makes 4340 the go-to choice for demanding applications such as heavy-duty drive shafts, crankshafts, and aircraft landing gear where performance under extreme cyclic loading is essential.
Finishes and Post-Processing Options
The zinc alloy substrate is highly suitable for various surface treatments to enhance decoration, protection, or functionality:
Electroplating: Such as chrome, nickel, gold, or silver plating, providing a highly decorative appearance, excellent wear and corrosion resistance. This is the most common choice.
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Passivation or Chromate Conversion Coating:
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Powder Coating:
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Painting:
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Physical Vapor Deposition (PVD):
Design and Machining Considerations
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Process Selection:
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Design Considerations:
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Material Selection:
Zamak 3 and 5 are suitable for the vast majority of general-purpose parts requiring good appearance and strength; ZA-8 is better for wear and bearing applications; for making rapid tooling, choose specialized alloys like Kirksite.
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