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China Stainless Steel CNC Machining Factory: Precision Parts Manufacturing by Trusted Suppliers
Specialized Stainless Steel Material Library
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.
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.
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.
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.
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.
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.
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.
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.
Nitronic 60 (218 SS)
High-Performance Stainless Steel
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.
Frequently Asked Questions
Q
What is the difference between 304 and 316 stainless steel?
The primary difference is that 316 stainless steel contains molybdenum (typically 2–3%), which significantly enhances its resistance to chloride corrosion and pitting. This makes 316 the preferred choice for marine, pharmaceutical, and chemical environments, while 304 is more commonly used in general food processing and architectural applications.
Q
What does "free-machining" mean in stainless steel grades like 303 and 416?
Free-machining stainless steels contain added sulfur (and sometimes selenium) that improves chip breakability and reduces cutting tool wear during machining operations. This makes grades like 303 and 416 significantly easier and more economical to machine at high volumes compared to standard austenitic or martensitic grades.
Q
What are precipitation-hardening (PH) stainless steels, and when should I use them?
Precipitation-hardening stainless steels such as 17-4 PH and 15-5 PH achieve very high strength through an aging (precipitation hardening) heat treatment process. They combine the corrosion resistance of stainless steel with mechanical properties approaching those of alloy steels, making them ideal for aerospace components, high-stress structural parts, and marine hardware where both strength and corrosion resistance are critical.
Q
Which stainless steel grade offers the highest hardness and wear resistance?
440C stainless steel offers the highest hardness among all stainless steel grades, capable of being hardened to HRC 58 or above. Its high carbon and chromium content provide exceptional wear resistance, making it the top choice for precision bearings, surgical instruments, valve components, and high-quality cutlery.
Q
What is Nitronic 60 and what makes it unique compared to standard stainless steels?
Nitronic 60 (218 SS) is a nitrogen-strengthened austenitic stainless steel that stands out for its outstanding resistance to galling and seizing — a type of adhesive wear that occurs when metal surfaces slide against each other under load. Unlike standard stainless steels, Nitronic 60 maintains this anti-galling property without requiring additional coatings or treatments, making it highly suitable for bushings, valve seats, bearings, and food processing equipment.
Q
How do I choose between 410, 420, and 440C martensitic stainless steels?
The choice depends on the required balance of hardness, toughness, and corrosion resistance. 410 provides moderate hardness and good general corrosion resistance, suitable for general-purpose applications. 420 has higher carbon content, enabling greater hardness after heat treatment, and is commonly used for cutlery and molds. 440C has the highest carbon content of the three, achieving maximum hardness and wear resistance, making it best suited for precision instruments, high-end bearings, and cutting tools where wear performance is the top priority.
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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