MATERIAL EXPERTISE
Stainless Steel CNC Machining
We provide high-precision stainless steel CNC machining services for prototypes and small-batch production. Stainless steel offers excellent corrosion resistance, high strength, and superior durability, making it one of the most widely used materials across industries.
- Tolerance up to ±0.002 mm on reviewed features
- Grades: 304/304L, 316/316L, 17-4 PH, 420, 440C and 303
- Prototype lead time: 1–7 days, subject to project review
- MOQ: 1 piece
Tolerance and delivery depend on geometry, size, material condition, finishing, quantity and inspection requirements.
Trusted by industry leaders
Why Choose Stainless Steel for CNC Machining?
At 6CNC, stainless steel is one of our most machined metal materials. It combines outstanding corrosion resistance, mechanical strength, hygiene, and aesthetic appeal, making it ideal for both functional and visible components.
Key Advantages
- Excellent corrosion and oxidation resistance
- High strength and durability
- Grade-specific machining strategies, including free-machining 303
- Hygienic and easy to clean (ideal for food and medical)
- High temperature resistance
- Non-magnetic options available (austenitic grades)
- Excellent weldability and formability
- Long service life with minimal maintenance
Popular Stainless Steel Grades
304 / 304L Stainless Steel
The most versatile and commonly used grade. Offers good corrosion resistance, excellent formability, and weldability. Ideal for general-purpose parts, food equipment, and architectural components.
316 / 316L Stainless Steel
Superior corrosion resistance, especially against chlorides and acids. Widely used in marine, chemical processing, medical, and pharmaceutical applications. 316L has lower carbon content for better weldability.
17-4PH (630) Stainless Steel
Precipitation-hardening grade that can be heat-treated to achieve high strength and hardness. Excellent combination of strength, corrosion resistance, and fatigue performance. Popular in aerospace, oil & gas, and high-load components.
420 Stainless Steel
Hardenable martensitic stainless for wear-resistant mechanical parts. Plan machining and heat treatment around the specified final hardness.
440C Stainless Steel
High-carbon stainless for bearing-type and wear components. Heat treatment, grinding allowance and final inspection form part of the process plan.
303 Stainless Steel
Free-machining grade with added sulfur for improved chip breaking and faster machining. Suitable for high-volume precision parts where corrosion resistance is moderate.
Other Grades
430 (decorative), 2205 Duplex (high strength + corrosion), etc.
| Grade | Selection consideration | Machining consideration | Typical use |
|---|---|---|---|
| 304/304L | General corrosion resistance | Work-hardening control | General equipment and fluid components |
| 316/316L | Improved chloride resistance relative to 304 | Heat and chip control | Marine, chemical and medical equipment |
| 17-4 PH | Strength depends on aging condition | Plan before and after aging | Shafts and loaded mechanical parts |
| 420 | Hardenable martensitic stainless | Annealed machining; finish after hardening | Wear-resistant components |
| 440C | High hardness after heat treatment | Grinding often required after hardening | Bearing-type and wear parts |
| 303 | Free-machining stainless | Improved chip breaking | General precision components |
Material performance depends on the exact specification, product form, environment and heat-treatment condition. Review the grade against your drawing and stock certificate.
Surface Finishes for Stainless Steel Parts
We offer a wide range of professional surface finishing options for stainless steel to improve corrosion resistance, appearance, cleanliness, and functional performance. Each finish is selected based on your specific application requirements.
As Machined
The most common and cost-effective finish. Parts come directly from the CNC machine with excellent dimensional accuracy. Typical surface roughness Ra 1.6–3.2 µm. Ideal for functional components where appearance is not critical. With optimized parameters, we can achieve finer finishes up to Ra 0.8–1.6 µm.
Bead Blasting / Sandblasting
Creates a uniform, non-reflective matte surface. Effectively removes machining marks, burrs, and surface contaminants. This finish is commonly used as a base for further treatments or for parts that require a consistent aesthetic appearance without high gloss.
Brushing (Satin Finish)
Produces a directional brushed/satin texture that is very popular for consumer products, architectural components, and kitchen equipment. It effectively hides fingerprints and minor scratches while maintaining an elegant modern look.
Polishing & Mirror Polishing
We offer multi-stage mechanical polishing from standard polish to high-gloss mirror finish (Ra < 0.2 µm). Mirror polishing is ideal for medical devices, food contact surfaces, optical components, and high-end visible parts. It significantly improves both aesthetics and cleanability.
Passivation
A critical chemical treatment for stainless steel. It removes free iron from the surface and enhances the natural passive oxide layer, greatly improving corrosion resistance. We strongly recommend passivation for all stainless steel parts, especially for medical, food, marine, and outdoor applications. We follow ASTM A967 and AMS 2700 standards.
Electropolishing
An electrochemical process that removes a thin layer of material, resulting in an ultra-smooth, bright surface. Benefits include:
Superior corrosion resistance
Excellent cleanability and reduced bacterial adhesion
Deburring of micro edges
Enhanced fatigue resistance
Particularly recommended for medical implants, pharmaceutical equipment, and food processing parts.
Powder Coating
High-durability colored finish with excellent corrosion protection. Available in a wide range of colors and textures. Suitable for outdoor equipment, automotive parts, and architectural applications.
Other Surface Treatments
Black Oxide (for specific applications)
PVD Coating (for enhanced wear resistance and decorative colors)
Laser Marking / Engraving (permanent, high-contrast marking without damaging the passive layer)
Ultrasonic Cleaning & Clean Room Packaging
Heat Treatment (solution annealing for 17-4PH, stress relieving, etc.)
Surface roughness values are existing 6CNC capability references, subject to geometry, access, stock condition and the agreed finishing process. Confirm applicable passivation specifications and acceptance criteria at quotation.
6CNC Stainless Steel Machining Capabilities
- 3-axis, 4-axis, and 5-axis CNC milling
- CNC turning and mill-turn composite machining
- Optimized tooling and parameters for different stainless grades
- Tight tolerance as precise as ±0.002 mm
- Passivation and electropolishing services
- Strict quality control with CMM inspection reports
- Material traceability and clean room packaging available
- Stress relieving and heat treatment (for 17-4PH)
- One-stop service: machining + finishing + assembly
The ±0.002 mm capability applies only to suitable, reviewed features; final tolerances and inspection methods are agreed against the drawing.
Main Applications
Our stainless steel CNC machined parts are widely used in:
- Medical & Pharmaceutical equipment
- Food & Beverage processing machinery
- Marine & Offshore applications
- Aerospace & Defense components
- Chemical and Petrochemical industry
- Automotive and New Energy
- Architectural & Decorative parts
- Industrial automation and robotics
Why Choose 6CNC for Stainless Steel Parts?
- 10+ years specializing in precision metal machining
- 140+ advanced CNC machines
- Expert DFM feedback to optimize design for stainless steel
- Strict quality control with material traceability
- Professional passivation and surface treatment capabilities
- Fast quotation and reliable delivery
- Competitive pricing for prototypes and small batches
We help you select the right grade, reduce machining costs, and ensure long-term performance of your stainless steel components.
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