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Alloy Steel CNC Machining Services | China Suppliers & Factory with 10+ Years Experience
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
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Low-Carbon
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.
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Free-Machining
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)
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Cr-Mo Alloy
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.
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Cr-Mo Alloy
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.
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Pre-Hardened
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.
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High-Strength
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)
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Air-Hardening
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.
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Oil-Hardening
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.
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Frequently Asked Questions
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What is the difference between 4130 and 4140 steel?
Both are chromium-molybdenum alloy steels, but 4140 has a higher carbon content, resulting in greater strength and hardness after heat treatment. 4130 offers better weldability and is preferred for aerospace tubing and lightweight structures, while 4140 is favored for high-load mechanical components such as gears and shafts.
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When should I choose 4140 PH (Pre-Hardened) over standard 4140 steel?
4140 PH is ideal when you need consistent mechanical properties right off the shelf and want to avoid the risk of dimensional distortion from post-machining heat treatment. It is especially suitable for dies, fixtures, and precision mechanical components where tight tolerances must be maintained.
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What makes 4340 steel suitable for critical aerospace and automotive applications?
4340 is a nickel-chromium-molybdenum alloy steel that delivers exceptional tensile strength, toughness, and fatigue resistance even in large cross-sections. These properties make it the material of choice for aircraft landing gear, heavy-duty drive shafts, and high-performance crankshafts where failure is not an option.
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What is the advantage of 1215 free-machining steel over standard low-carbon steels?
1215 steel contains higher sulfur and phosphorus levels that promote excellent chip-breaking during machining. This results in faster cutting speeds, improved surface finish, and longer tool life compared to standard low-carbon steels like 1018, making it particularly cost-effective for high-volume production of bolts, nuts, and bushings.
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How do A2 and O1 tool steels differ in their applications?
A2 is an air-hardening tool steel offering minimal distortion during heat treatment, making it ideal for precision stamping dies and gauges. O1 is an oil-hardening steel known for its excellent edge retention and ease of heat treatment, making it a go-to choice for hand tools, cutting tools, and general-purpose molds where simplicity and sharpness are priorities.
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Can 1018 steel be hardened to improve its 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 and quenching. This creates a hard, wear-resistant outer surface while retaining a tough, ductile core — making it well-suited for shafts, pins, and gears that require both surface hardness and impact resistance.
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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