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Stainless Steel CNC Machining Services - China Suppliers and 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:
Specialized Stainless Steel Material Library
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304/304L (18-8) — Most Versatile Choice
Superior corrosion resistance, formability, and weldability. Widely used in food processing, chemical, medical device, and general machinery applications.
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316/316L — Best for Harsh Environments
Molybdenum-enhanced with significantly better resistance to chloride corrosion and pitting. Preferred for marine, pharmaceutical, and high-end medical device industries.
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17-4 PH (630) — Top Precipitation-Hardening Grade
Achieves high strength (up to H1100 condition) through aging treatment while maintaining good corrosion resistance. Ideal for aerospace, marine, and high-stress structural applications.
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Austenitic · Free-Machining
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.
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Austenitic · General Purpose
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.
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Austenitic · Molybdenum-Enhanced
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.
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Martensitic · Free-Machining
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.
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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.
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Precipitation-Hardening · Improved
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.
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Martensitic · General Purpose
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.
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Martensitic · Highest 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.
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Austenitic · Nitrogen-Strengthened
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.
Frequently Asked Questions
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What is the difference between 304 and 316 stainless steel?
The primary difference is the addition of molybdenum in 316 stainless steel (approximately 2–3%). This makes 316 significantly more resistant to chloride corrosion, pitting, and crevice corrosion compared to 304. As a result, 316 is preferred in marine environments, chemical processing, and pharmaceutical applications, while 304 is sufficient for most general-purpose and food-grade uses.
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Which stainless steel grade is best for high-strength structural applications?
Precipitation-hardening grades such as 17-4 PH (630) and 15-5 PH are the top choices for high-strength structural applications. They offer an excellent combination of high tensile strength, good corrosion resistance, and the ability to be aged to various strength levels (H900 to H1150). These grades are widely specified in aerospace, defense, and marine structural components.
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What makes 303 and 416 stainless steel good for machining?
Both 303 and 416 are classified as free-machining stainless steels. They contain added sulfur (and in some cases selenium) which creates discontinuities in the material that act as chip-breakers during machining. This significantly reduces tool wear and cycle times, making them ideal for high-volume CNC production of threaded parts, fittings, shafts, and gears — though at a slight reduction in corrosion resistance and toughness compared to standard grades.
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When should I choose 440C stainless steel over other grades?
440C is the go-to choice when maximum hardness and wear resistance are the primary requirements. With a hardness potential of HRC 58+, it outperforms all other standard stainless steel grades in applications such as precision bearings, valve seats, surgical instruments, and high-quality cutting tools. However, it offers lower corrosion resistance than austenitic grades like 304 or 316, so it is best suited for dry or low-humidity environments.
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What is Nitronic 60 and what advantages does it offer over standard stainless steels?
Nitronic 60 (also known as 218 SS) is a nitrogen-strengthened austenitic stainless steel developed specifically to resist galling and seizing — two forms of severe adhesive wear that standard stainless steels are highly susceptible to. Compared to 316 stainless steel, Nitronic 60 offers approximately twice the yield strength, superior anti-galling performance, and comparable or better corrosion resistance. It is the preferred material for bearings, bushings, valve seats, and food processing components under high contact-stress conditions.
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How do I choose between 410 and 420 stainless steel?
Both 410 and 420 are general-purpose martensitic stainless steels, but they differ in carbon content. 410 has lower carbon content, offering moderate hardness and better ductility and toughness, making it suitable for general structural and valve components. 420 has a higher carbon content, which allows it to achieve significantly greater hardness (up to HRC 50+) after heat treatment, making it preferred for cutlery, molds, and wear-resistant applications where a sharper, harder surface is required.
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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