+86-13928348837
Alloy Steel CNC Machining Services | China Suppliers & Factory for High-Quality Parts
Common Alloy Steel Material Library
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
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.
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)
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.
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.
Pre-Hardened
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.
Ni-Cr-Mo Alloy
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)
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.
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.
Frequently Asked Questions
Q What is the difference between 4140 and 4140 PH steel?
4140 Steel is supplied in an annealed or normalized condition and requires heat treatment after machining to reach the desired hardness. 4140 PH (Pre-Hardened) is already quenched and tempered to approximately HRC 28–32 before delivery, allowing it to be machined directly into finished parts without additional heat treatment — minimizing dimensional distortion and lead time.
Q Which alloy steel is best suited for aerospace and high-performance applications?
4340 Steel is the top choice for aerospace and high-performance applications due to its exceptional combination of high strength, toughness, and fatigue resistance. It is the preferred material for aircraft landing gear, heavy-duty drive shafts, and racing crankshafts. 4130 Steel is also widely used in aerospace structural tubing and race car chassis where weldability is a priority.
Q What makes 1215 steel ideal for high-volume production?
1215 Steel is a high-sulfur free-machining steel that produces short, brittle chips during cutting, reducing tool wear and enabling faster machining speeds. This results in excellent surface finish quality and lower production costs, making it highly suitable for mass manufacturing of standard components such as bolts, nuts, and bushings.
Q What is the key difference between A2 and O1 tool steel?
A2 Tool Steel is air-hardened, which results in minimal distortion during heat treatment — making it ideal for precision dies and gauges that require tight dimensional tolerances. O1 Tool Steel is oil-hardened and is known for its excellent edge retention and ease of heat treatment, making it a popular choice for cutting tools, hand tools, and low-volume molds.
Q Can 1018 steel be surface-hardened while keeping a tough core?
Yes. 1018 Steel is well-suited for case hardening processes such as carburizing followed by quenching. This treatment creates a hard, wear-resistant outer surface while retaining a tough, ductile core — making it an excellent choice for components like shafts, pins, and gears that must withstand both surface wear and impact loading.
Q How do I choose the right alloy steel for my machining project?
Selecting the right alloy steel depends on several factors: the required mechanical properties (strength, hardness, toughness), machinability requirements, heat treatment capabilities, and the final application environment. For general structural parts, 4140 or 4130 are reliable choices. For high-precision tooling, A2 or O1 are preferred. For high-volume turned parts, 1215 offers the best efficiency. Our team can assist you in selecting the optimal material based on your specific project requirements.
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.
-
Passivation or Chromate Conversion Coating:
-
Powder Coating:
-
Painting:
-
Physical Vapor Deposition (PVD):
Design and Machining Considerations
-
Process Selection:
-
Design Considerations:
-
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.
Ready to Start Your CNC Project?
Send us your drawings to receive professional manufacturing solutions.