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China Stainless Steel CNC Machining: Top Suppliers & Reliable Factory for Precision Parts Manufacturing
We maintain a full inventory of austenitic, martensitic, precipitation-hardening, and specialty stainless steels to meet the most demanding mechanical performance and corrosion resistance requirements:
Austenitic
303 Stainless Steel
A free-machining austenitic stainless steel with excellent machinability, ideal for high-volume automated parts, threaded components, and fittings requiring good corrosion resistance.
Austenitic
304 / 304L (18-8) Stainless Steel
The most versatile austenitic stainless steel, offering superior corrosion resistance, formability, and weldability. Widely used in food processing, chemical, medical device, and general machinery applications.
Austenitic — Premium
316 / 316L Stainless Steel
Molybdenum-enhanced austenitic stainless steel with significantly better resistance to chloride corrosion and pitting than 304 series. The preferred choice for marine environments, chemical equipment, high-end medical devices, and pharmaceutical industries.
Martensitic
416 Stainless Steel
A free-machining martensitic stainless steel that achieves higher strength through heat treatment. Suitable for shafts, gears, and valve components requiring good machinability along with moderate strength and corrosion resistance.
Precipitation-Hardening
17-4 PH (630) Stainless Steel
The most widely used precipitation-hardening stainless steel. It achieves high strength (up to H1100 condition) through aging treatment while maintaining good corrosion resistance. Ideal for aerospace, marine, and high-stress structural applications.
Precipitation-Hardening
15-5 PH Stainless Steel
An improved precipitation-hardening stainless steel with performance similar to 17-4 PH, but offering better transverse toughness and dimensional stability during heat treatment.
Martensitic
410 & 420 Stainless Steel
General-purpose martensitic stainless steels. 410 offers moderate strength and corrosion resistance; 420, with higher carbon content, achieves greater hardness through heat treatment. Commonly used in cutlery, shafts, molds, and wear-resistant parts.
Martensitic — High Hardness
440C Stainless Steel
A high-carbon, high-chromium martensitic stainless steel with the highest hardness among stainless steels (can be hardened to HRC 58+). Exceptional wear resistance makes it ideal for high-end bearings, valve components, surgical instruments, and cutlery.
Nitrogen-Strengthened Austenitic
Nitronic 60 (218 SS)
A high-performance nitrogen-strengthened austenitic stainless steel offering an exceptional combination of high wear resistance, strength, and corrosion resistance. Particularly suitable for critical applications involving galling and seizing resistance, such as bearings, valve seats, bushings, and food processing equipment.
Q
What is the difference between 304 and 316 stainless steel, and how do I choose?
Both are popular austenitic grades, but 316/316L contains molybdenum, which significantly improves resistance to chloride-induced corrosion and pitting. If your application involves exposure to saltwater, marine environments, chlorinated chemicals, or pharmaceutical processes, 316/316L is the preferred choice. For general indoor or mild-environment applications, 304/304L is more cost-effective.
Q
When should I use precipitation-hardening stainless steels like 17-4 PH or 15-5 PH instead of standard grades?
Precipitation-hardening grades such as 17-4 PH and 15-5 PH are ideal when you need a combination of high strength, good corrosion resistance, and the ability to machine parts before final hardening. They are commonly specified for aerospace components, structural parts, and high-stress applications where standard austenitic grades lack sufficient strength.
Q
What makes 440C stainless steel unique compared to other stainless steel grades?
440C is distinguished by its exceptionally high carbon and chromium content, enabling it to achieve the highest hardness of any stainless steel — up to HRC 58+ after heat treatment. This makes it the top choice for applications demanding extreme wear resistance, such as precision bearings, surgical instruments, high-end cutlery, and valve seats.
Q
What is Nitronic 60 and why is it preferred for galling-prone applications?
Nitronic 60 (218 SS) is a nitrogen-strengthened austenitic stainless steel specifically engineered to resist galling and seizing — a common problem in metal-to-metal contact under load. Its unique nitrogen-enhanced microstructure provides significantly higher wear resistance than standard 304 or 316, making it ideal for bushings, valve seats, bearings, and food processing equipment where galling failure is a concern.
Q
Can martensitic stainless steels like 416 or 410 be hardened, and what are their limitations?
Yes, martensitic stainless steels such as 416, 410, and 420 can be hardened through heat treatment, making them suitable for applications requiring higher strength or wear resistance. However, they offer lower corrosion resistance compared to austenitic grades and are generally not recommended for highly corrosive or marine environments. They are best suited for shafts, gears, cutlery, and mold components in moderate-exposure conditions.
Q
What is the "L" designation in grades like 304L and 316L, and does it affect performance?
The "L" designation stands for "low carbon," indicating a maximum carbon content of 0.03%. This reduced carbon level minimizes the risk of sensitization — a process where chromium carbides precipitate at grain boundaries during welding, reducing corrosion resistance in the heat-affected zone. 304L and 316L are therefore strongly preferred for welded assemblies and components that will be used in corrosive environments after fabrication.
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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