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China Alloy Steel CNC Machining: High-Quality Parts from Reliable Suppliers and 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
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.
⭐ Pre-Hardened — No Post-Heat Treatment Needed
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.
⭐ Preferred for Critical Load-Bearing Parts
🛠️ 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?
Standard 4140 Steel is supplied in an annealed or normalized condition and requires quenching & tempering after machining to achieve desired hardness. 4140 PH (Pre-Hardened) Steel is already heat-treated to approximately HRC 28–32 before delivery, allowing it to be machined directly and used without further heat treatment — reducing lead time and eliminating the risk of post-machining distortion.
Q
When should I choose 4340 Steel over 4140 Steel?
4340 Steel is preferred when the application involves large cross-sections, extremely high loads, or demanding fatigue conditions — such as aircraft landing gear or heavy-duty crankshafts. Its nickel content provides superior hardenability and toughness compared to 4140, making it the go-to choice for the most critical structural components.
Q
What makes 1215 Steel ideal for high-volume CNC machining?
1215 Steel contains elevated sulfur and phosphorus levels, which act as chip-breakers during machining. This results in shorter, more manageable chips, reduced tool wear, higher cutting speeds, and superior surface finishes. These properties make it highly cost-effective for mass-producing small standard parts like bolts, nuts, and bushings.
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 distortion during heat treatment compared to oil-hardening or water-hardening steels. This makes it especially suitable for precision tooling applications — such as stamping dies and gauges — where dimensional accuracy after hardening is critical.
Q
Can 1018 Steel be used without heat treatment?
Yes. 1018 Steel can be used in its as-rolled or normalized condition for many general-purpose applications. However, when surface hardness and wear resistance are required — such as for gears or shafts — it can be carburized and quenched to create a hard outer case while maintaining a tough, ductile core.
Q
How do I choose between O1 and A2 Tool Steel for my tooling application?
O1 Tool Steel is an excellent choice when ease of machining, simple heat treatment, and cost-efficiency are priorities — ideal for hand tools, gauges, and low-volume molds. A2 Tool Steel is the better option when dimensional stability after hardening is essential, as its air-hardening process minimizes distortion. For high-precision dies and production tooling, A2 is generally preferred.
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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