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China Alloy Steel CNC Machining Factory: Leading Suppliers for High-Quality Custom Parts and Precision Solutions
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.
Shafts
Pins
Gears
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.
Bolts
Nuts
Bushings
⚙️ Chromium-Molybdenum Alloy Structural Steel (High-Strength)
4130 Steel Cr-Mo
A chromium-molybdenum alloy steel with excellent strength, toughness, and weldability. A classic material for aerospace structural tubing and high-performance racing chassis, typically normalized or quenched & tempered.
Aircraft Engine Mounts
Racing Chassis
4140 Steel Cr-Mo
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.
Gears
Shafts
Couplings
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.
Dies
Mechanical Components
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.
Aircraft Landing Gear
Drive Shafts
Crankshafts
🔧 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.
Stamping Dies
Shear Blades
Gauges
O1 Tool Steel Oil-Hardening
An oil-hardening general-purpose tool steel renowned for excellent edge retention, machinability, and simple heat treatment process.
Hand Tools
Gauges
Cutting Tools
Molds
❓ 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 delivered already quenched and tempered to approximately HRC 28–32, allowing it to be machined directly to final dimensions without additional heat treatment — significantly reducing the risk of dimensional distortion.
Q
Which alloy steel is best suited for aerospace and high-performance applications?
4340 Steel is generally considered the top choice for critical aerospace and high-performance applications. Its nickel-chromium-molybdenum composition delivers exceptional strength, toughness, and fatigue resistance — making it the standard material for aircraft landing gear, heavy-duty drive shafts, and high-performance crankshafts. 4130 Steel is also widely used for aerospace structural tubing due to its excellent weldability and strength-to-weight ratio.
Q
What makes 1215 Steel ideal for high-volume CNC machining?
1215 Steel contains elevated sulfur and phosphorus levels that promote excellent chip-breaking during machining operations. This results in faster cutting speeds, improved surface finish quality, and extended tool life — all of which reduce per-part costs in high-volume production environments. It is commonly used for bolts, nuts, bushings, and other standard fastener components.
Q
What is the key advantage of A2 Tool Steel over other cold-work tool steels?
A2 Tool Steel is air-hardening, which means it undergoes significantly less dimensional distortion during heat treatment compared to oil-hardening or water-hardening grades. This makes it particularly suitable for precision tooling applications such as stamping dies, shear blades, and gauges where tight tolerances must be maintained after hardening.
Q
Can 1018 Steel be hardened for wear-resistant applications?
Yes. Although 1018 is a low-carbon steel and cannot be through-hardened effectively, it responds very well to case hardening processes such as carburizing and carbonitriding. These processes create a hard, wear-resistant outer surface while maintaining a tough, ductile core — making it suitable for components like shafts, pins, and gears that require surface wear resistance combined with core impact toughness.
Q
How do I choose between O1 and A2 Tool Steel for my tooling project?
The choice depends primarily on your dimensional tolerance requirements and production volume. O1 Tool Steel offers excellent machinability and edge retention at a lower cost, making it ideal for hand tools, gauges, and low-volume molds. However, it requires oil quenching, which can introduce slight distortion. A2 Tool Steel, being air-hardening, offers better dimensional stability after heat treatment and is preferred for precision dies and high-accuracy tooling where post-hardening grinding must be minimized.
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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