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China Alloy Steel CNC Machining Suppliers - Precision Parts from a Leading 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
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 (Pre-Hardened) Steel?
Standard 4140 Steel is supplied in an annealed or normalized condition and requires heat treatment after machining to achieve the desired hardness. 4140 PH Steel is pre-quenched and tempered to a hardness of approximately HRC 28–32, allowing it to be machined directly without additional heat treatment — reducing lead time and minimizing the risk of post-treatment distortion.
Q
Which alloy steel is best suited for aerospace and high-performance racing applications?
4130 Steel is widely used for aerospace structural tubing and racing chassis due to its excellent balance of strength, toughness, and weldability. For even more demanding applications — such as aircraft landing gear and heavy-duty crankshafts — 4340 Steel is preferred, thanks to its superior fatigue resistance and performance in large cross-sections.
Q
What makes 1215 Steel ideal for high-volume CNC machining?
1215 Steel is a free-machining steel with added sulfur content, which promotes excellent chip-breaking during cutting operations. This allows for faster machining speeds, improved surface finish, and extended tool life — making it highly cost-effective for mass production of precision fasteners, bushings, and small turned components.
Q
What is the key advantage of A2 Tool Steel over other cold-work tool steels?
A2 Tool Steel is an air-hardening steel, meaning it achieves hardness by cooling in still air rather than in oil or water. This results in significantly less distortion and cracking during heat treatment compared to oil-hardening grades like O1. It offers a good combination of wear resistance and toughness, making it ideal for precision dies, punches, and gauges where dimensional stability is critical.
Q
Can 1018 Steel be surface hardened, and what process is used?
Yes. Although 1018 is a low-carbon steel and cannot be through-hardened effectively, it is well-suited for case hardening processes such as carburizing or carbonitriding. These processes introduce carbon (and nitrogen) into the surface layer, creating a hard, wear-resistant case while retaining a tough, ductile core — ideal for components like shafts, pins, and gears that require surface durability and impact resistance.
Q
How do I choose between O1 and A2 Tool Steel for my tooling application?
If your priority is ease of machining, excellent edge retention, and straightforward heat treatment at lower cost, O1 Tool Steel is a practical choice — particularly for hand tools, gauges, and short-run molds. If your application demands tighter dimensional tolerances after hardening, or involves more complex die geometries where distortion must be minimized, A2 Tool Steel's air-hardening characteristic provides a clear advantage.
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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