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Alloy Steel CNC Machining: Top China Suppliers & Factory for Precision Parts and Prototypes
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 1018 and 1215 steel?
1018 is a general-purpose low-carbon steel known for excellent weldability and machinability, often surface-hardened for parts like shafts and gears. 1215 is a high-sulfur free-machining steel optimized for rapid machining speeds and clean chip-breaking, making it ideal for mass-producing fasteners and bushings.
Q: Why choose 4140 PH (Pre-Hardened) steel?
4140 PH is supplied pre-quenched and tempered (HRC 28–32), allowing it to be machined directly into final components. This eliminates the need for post-machining heat treatment, avoiding the risks of dimensional deformation and cracking.
Q: What makes 4340 steel ideal for heavy-duty applications?
4340 is a nickel-chromium-molybdenum alloy steel that provides exceptional strength, toughness, and fatigue resistance. It is highly suitable for large-section, critical load-bearing components like aircraft landing gear and heavy-duty drive shafts.
Q: How do A2 and O1 tool steels differ in heat treatment?
A2 tool steel is air-hardening, which ensures minimal dimensional distortion during heat treatment. O1 tool steel is oil-hardening, offering excellent edge retention and simple heat treatment processes ideal for lower-run molds and hand tools.
Q: What are the primary uses of 4130 steel?
4130 steel is a chromium-molybdenum alloy with outstanding toughness and weldability. It is widely used in normalized or quenched & tempered forms for aerospace structural tubing, aircraft engine mounts, and high-performance racing chassis.
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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