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Stainless Steel CNC Machining Services by China Suppliers - Precision Parts from a Leading Factory
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:
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
Free-Machining
Threaded Parts
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
Food Processing
Medical Devices
Weldable
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.
Molybdenum-Enhanced
Marine Grade
Pharma
Pitting Resistant
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.
Martensitic
Heat Treatable
Gears & Shafts
17-4 PH (630) Stainless Steel — Most Widely Used Precipitation-Hardening Grade
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
Aerospace
High Strength
Marine
Structural
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.
Precipitation-Hardening
High Toughness
Dimensional Stability
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
Cutlery
Molds
Wear Resistant
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.
HRC 58+
Max Hardness
Bearings
Surgical
Nitronic 60 (218 SS) — High-Performance Nitrogen-Strengthened Grade
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.
Nitrogen-Strengthened
Galling Resistant
Valve Seats
Bushings
Food Processing
Q
What is the difference between 304 and 316 stainless steel?
316 stainless steel contains molybdenum (approximately 2–3%), which significantly improves its resistance to chloride corrosion and pitting compared to 304. This makes 316 the preferred choice for marine environments, pharmaceutical applications, and exposure to harsh chemicals, while 304 is more cost-effective for general-purpose use.
Q
What does "precipitation-hardening" mean in stainless steel grades like 17-4 PH and 15-5 PH?
Precipitation-hardening (PH) stainless steels are strengthened through a controlled aging heat treatment process, during which fine particles precipitate within the metal matrix. This allows these grades to achieve very high strength levels while retaining good corrosion resistance — a combination that is difficult to achieve with standard austenitic or martensitic grades alone.
Q
Which stainless steel grade offers the highest hardness?
440C stainless steel offers the highest hardness among stainless steels, capable of being hardened to HRC 58 or above. Its high carbon and chromium content make it the top choice for applications demanding extreme wear resistance, such as precision bearings, cutting instruments, and valve components.
Q
When should I choose Nitronic 60 over standard austenitic stainless steels?
Nitronic 60 should be selected when galling, seizing, or severe wear between mating metal surfaces is a concern. Its nitrogen-strengthened microstructure provides outstanding anti-galling properties that standard grades like 304 or 316 cannot match, making it ideal for valve seats, bushings, fasteners, and food processing equipment operating under sliding contact.
Q
What is the advantage of using free-machining stainless steels like 303 and 416?
Free-machining grades such as 303 (austenitic) and 416 (martensitic) contain sulfur or selenium additions that improve chip breaking and reduce tool wear during CNC machining. This results in faster cycle times, lower tooling costs, and better surface finishes — making them highly cost-effective for high-volume precision turned parts, threaded components, and fittings.
Q
How do I choose between 410 and 420 stainless steel for my application?
Both 410 and 420 are general-purpose martensitic stainless steels, but 420 has a higher carbon content, allowing it to achieve greater hardness after heat treatment. Choose 410 when moderate strength and corrosion resistance are sufficient (e.g., structural parts, shafts). Choose 420 when higher hardness and wear resistance are required, such as in cutlery blades, molds, and precision wear parts.
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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