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Alloy Steel CNC Machining Services from China Suppliers | High-Performance Factory Solutions
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.
Low-Carbon Steel / Free-Machining Steel
1018 Steel
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.
1215 Steel
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.
Chromium-Molybdenum Alloy Structural Steel (High-Strength)
4130 Steel
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.
4140 Steel
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.
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.
4340 Steel
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.
Tool Steel (High Wear Resistance / High Hardness)
A2 Tool Steel
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.
O1 Tool Steel
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.
Frequently Asked Questions
Q
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 achieve 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 additional heat treatment, which reduces the risk of dimensional distortion.
Q
Which alloy steel is best suited for aerospace applications?
4130 Steel and 4340 Steel are both widely used in aerospace. 4130 is commonly chosen for structural tubing and engine mounts due to its excellent weldability and strength-to-weight ratio. 4340 is preferred for highly stressed components such as landing gear and drive shafts, thanks to its superior strength, toughness, and fatigue resistance in large cross-sections.
Q
What makes 1215 Steel a good choice for high-volume machining?
1215 Steel is a free-machining steel with elevated sulfur content, which improves chip-breaking and reduces tool wear. This allows for higher cutting speeds, better surface finishes, and lower machining costs — making it ideal for mass production of fasteners, bushings, and other standard components.
Q
How does A2 Tool Steel compare to O1 Tool Steel?
A2 Tool Steel is air-hardening, which results in less distortion during heat treatment and is better suited for precision tooling such as stamping dies and gauges. O1 Tool Steel is oil-hardening, offers excellent edge retention and ease of machining, and is a more economical choice for general-purpose tools, cutting tools, and low-volume molds.
Q
Can 1018 Steel be hardened for wear-resistant applications?
Yes. Although 1018 is a low-carbon steel with limited through-hardening capability, it responds well to surface carburizing and case hardening processes. This creates a hard, wear-resistant outer layer while retaining a tough, ductile core — making it suitable for components such as shafts, pins, and gears that require both surface hardness and impact resistance.
Q
What are the key advantages of 4340 Steel over other alloy steels?
4340 Steel contains nickel in addition to chromium and molybdenum, which significantly enhances its hardenability, toughness, and fatigue resistance — especially in large cross-sections where other steels may not harden uniformly. This makes 4340 the material of choice for heavy-duty, high-stress components such as crankshafts, drive shafts, and aircraft landing gear.
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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