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Alloy Steel CNC Machining Services by Leading China Suppliers | Quality Manufacturing at Our Factory
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:
🔩 Low-Carbon Steel / Free-Machining Steel
1018 Steel Low-Carbon
A general-purpose low-carbon steel with 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.
✔ Weldability
✔ Carburizing
✔ Machinability
1215 Steel Free-Machining
A high-sulfur free-machining steel with 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.
✔ High-Speed Machining
✔ Surface Finish
✔ Mass Production
⚙️ Chromium-Molybdenum Alloy Structural Steel (High-Strength)
4130 Steel Cr-Mo Alloy
A chromium-molybdenum alloy steel with 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.
✔ Aerospace
✔ Racing Chassis
✔ Weldability
4140 Steel Cr-Mo Alloy
One of the most widely used chromium-molybdenum alloy steels, offering high strength, good wear resistance, and impact toughness. Achieves different strength levels through quenching & tempering. Widely used for gears, shafts, couplings, and die sets.
✔ High Strength
✔ Wear Resistance
✔ Q&T Versatile
4140 PH Steel Pre-Hardened
Supplied in a pre-quenched & tempered condition (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.
✔ HRC 28–32
✔ No Heat Treatment
✔ Stable Properties
4340 Steel Ni-Cr-Mo
A high-strength nickel-chromium-molybdenum alloy steel with 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.
✔ Landing Gear
✔ Fatigue Resistance
✔ Heavy-Duty
🛠️ Tool Steel (High Wear Resistance / High Hardness)
A2 Tool Steel Air-Hardening
An air-hardening cold-work tool steel with good wear resistance, moderate toughness, and minimal heat treatment deformation. Widely used for precision stamping dies, shear blades, and gauges.
✔ Minimal Deformation
✔ Stamping Dies
✔ Gauges
O1 Tool Steel Oil-Hardening
An oil-hardening general-purpose tool steel renowned for excellent edge retention, machinability, and simple heat treatment. Commonly used for hand tools, gauges, cutting tools, and low-life molds.
✔ Edge Retention
✔ Easy Heat Treatment
✔ Cutting Tools
❓ Frequently Asked Questions
Q
What is the difference between 4140 Steel and 4140 PH Steel?
4140 Steel is typically supplied in an annealed or normalized condition and requires heat treatment after machining to achieve the desired hardness. 4140 PH (Pre-Hardened) Steel is already quenched and tempered to approximately HRC 28–32, allowing it to be machined directly into finished parts without additional heat treatment, which reduces the risk of dimensional distortion.
Q
Which alloy steel is best suited for aerospace applications?
4130 and 4340 steels are the most commonly selected for aerospace applications. 4130 is favored for structural tubing and engine mounts due to its excellent weldability and strength-to-weight ratio. 4340 is preferred for critical high-load components such as aircraft landing gear, thanks to its superior strength, toughness, and fatigue resistance in large cross-sections.
Q
What makes 1215 Steel ideal for high-volume machining production?
1215 Steel contains elevated levels of sulfur, which promotes excellent chip-breaking during machining. This results in faster cutting speeds, reduced tool wear, and superior surface finish quality — all of which significantly improve productivity and reduce costs in mass production environments for parts like bolts, nuts, and bushings.
Q
How do A2 and O1 Tool Steels differ in their applications?
A2 Tool Steel is air-hardened, which means it experiences minimal distortion during heat treatment, making it ideal for precision stamping dies, shear blades, and gauges where tight dimensional tolerances are critical. O1 Tool Steel is oil-hardened and is valued for its excellent edge retention and ease of heat treatment, making it a popular choice for hand tools, cutting tools, and general-purpose molds.
Q
Can 1018 Steel be surface hardened, and what processes are suitable?
Yes, 1018 Steel is well-suited for surface hardening. Its low carbon content makes it an excellent candidate for carburizing or carbonitriding, which introduces carbon (and nitrogen) into the surface layer. After quenching, the result is a hard, wear-resistant outer surface combined with a tough, ductile core — ideal for components like shafts, pins, and gears that require both surface hardness and impact resistance.
Q
Why is 4340 Steel preferred over 4140 Steel for heavy-duty drive shafts and crankshafts?
While 4140 offers excellent strength and toughness for many applications, 4340 Steel incorporates nickel in addition to chromium and molybdenum, which significantly enhances hardenability, fatigue strength, and toughness — especially in large cross-sections where 4140 may not fully through-harden. This makes 4340 the preferred choice for heavy-duty drive shafts, crankshafts, and other critical components subjected to high cyclic loads.
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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