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China Stainless Steel CNC Machining Factory - Reliable Suppliers for Precision Parts Manufacturing
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:
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 Most Versatile
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
316/316L Stainless Steel Marine Grade
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 Most Widely Used
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
440C Stainless Steel Highest Hardness
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.
Specialty / Nitrogen-Strengthened
Nitronic 60 (218 SS) High Performance
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?
The primary difference is the addition of molybdenum in 316/316L stainless steel. This makes 316 significantly more resistant to chloride corrosion, pitting, and crevice corrosion compared to 304. While 304 is suitable for general-purpose applications, 316 is preferred in marine environments, chemical processing, and pharmaceutical or medical device manufacturing where exposure to harsh chemicals or saltwater is a concern.
Q
When should I choose precipitation-hardening stainless steel like 17-4 PH over standard austenitic grades?
Precipitation-hardening grades such as 17-4 PH and 15-5 PH are the right choice when you need a combination of high strength, good corrosion resistance, and dimensional stability after heat treatment — properties that standard austenitic grades like 304 or 316 cannot provide. They are commonly specified 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 best machinability for high-volume CNC production?
303 stainless steel is specifically designed for high-volume CNC machining. Its free-machining formulation (with added sulfur) significantly improves chip breaking and tool life compared to 304 or 316. For martensitic grades, 416 stainless steel offers similar free-machining advantages. These grades are ideal when tight tolerances and fast cycle times are required on automated production lines.
Q
What makes 440C stainless steel the top choice for bearing and cutting applications?
440C stainless steel has the highest carbon content among standard stainless steel grades, which allows it to achieve hardness levels of HRC 58+ after heat treatment — the highest attainable hardness in the stainless steel family. This extreme hardness, combined with good corrosion resistance, makes it uniquely suited for high-end bearings, precision valve components, surgical instruments, and premium cutlery where edge retention and wear resistance are paramount.
Q
What is Nitronic 60 and why is it used in anti-galling applications?
Nitronic 60 (218 SS) is a nitrogen-strengthened austenitic stainless steel engineered specifically to resist galling and seizing — two common failure modes in metal-on-metal sliding contact. Unlike standard stainless steels that tend to gall under load, Nitronic 60 maintains a stable surface even under heavy contact stress. This makes it the preferred material for bushings, valve seats, fasteners, and food processing equipment where lubrication may be limited or unavailable.
Q
How do I choose between 410 and 420 stainless steel for my application?
The choice between 410 and 420 depends primarily on the hardness and wear resistance requirements of your application. 410 stainless steel provides moderate strength and corrosion resistance and is well-suited for general-purpose parts, structural components, and fasteners. 420, with its higher carbon content, can be hardened to a greater degree, making it the better option for applications demanding higher surface hardness, such as cutlery blades, molds, and wear-resistant mechanical 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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