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CNC Machining of Alloy Steel by Top Suppliers in China | Quality Factory Solutions for Precision Parts
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 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 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 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 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 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 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 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 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 and 4140 PH (Pre-Hardened) 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 is supplied already quenched and tempered to HRC 28–32, allowing it to be machined directly without additional heat treatment, which reduces the risk of dimensional distortion and simplifies the manufacturing process.
Q When should I choose 4340 steel over 4140 steel?
4340 steel should be chosen when the application demands higher strength, greater toughness, and superior fatigue resistance — especially for large cross-section components where full hardening through the entire section is critical. Typical examples include aircraft landing gear, heavy-duty crankshafts, and high-performance drive shafts. 4140 is generally sufficient for smaller, less critical structural parts.
Q What makes 1215 steel ideal for high-volume CNC machining?
1215 is a resulfurized and rephosphorized free-machining steel. The added sulfur creates manganese sulfide inclusions that act as chip breakers during cutting, resulting in shorter chips, reduced tool wear, and faster cutting speeds. This makes it highly efficient for automated CNC production of small standard parts like bolts, nuts, and bushings.
Q What is the main advantage of A2 tool steel over O1 tool steel?
The primary advantage of A2 tool steel is its air-hardening characteristic, which results in significantly less distortion and dimensional change during heat treatment compared to O1, which requires oil quenching. This makes A2 the preferred choice for precision dies and gauges where tight tolerances must be maintained after hardening. O1, however, offers better machinability and is more economical for general-purpose tooling applications.
Q Can 4130 steel be welded without pre-heating?
4130 steel has relatively good weldability among alloy steels due to its lower carbon content. For thin-section parts, welding can often be performed without pre-heating. However, for thicker sections or highly restrained joints, pre-heating to approximately 150–260°C (300–500°F) is recommended to minimize the risk of hydrogen-induced cracking and to ensure weld integrity, especially in aerospace or structural applications.
Q Which alloy steel is best suited for carburizing applications?
1018 steel is one of the most commonly used materials for carburizing applications. Its low carbon content allows the surface to absorb carbon effectively during the carburizing process, creating a hard, wear-resistant case while maintaining a tough, ductile core. This combination of surface hardness and core toughness makes it ideal for components like gears, shafts, and pins that must withstand both surface wear and impact loading.
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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