Black to dark gray
Color and sheen vary with steel chemistry, surface preparation, and the applied seal.
Oxidation
Black Oxide for Custom Manufactured Parts
A dark conversion treatment for ferrous components that produces minimal dimensional change.
- Dark appearance
- Minimal buildup
- Oil-assisted corrosion support
Finish overview
A dark steel conversion finish with minimal coating buildup.
Black oxide is used on carbon steel and tool steel components such as fixture hardware, rail blocks, tooling details, and machine parts that need a dark technical appearance with minimal dimensional change.
The conversion layer alone provides limited corrosion resistance and is commonly paired with oil, wax, or another seal. It should not be specified as a substitute for a robust outdoor coating without environmental validation.
Appearance
What the finished surface can look and feel like.
Base texture retained
Machining, grinding, and polishing patterns remain visible through the conversion finish.
Oiled sheen
Post-treatment oil or wax can deepen color and alter touch and cleanliness.
Suitable processes
Manufacturing routes commonly paired with this finish.
Suitable materials
Base materials that require process-specific review.
Typical applications
Part families commonly reviewed for black oxide.
Fixture hardware
Rail carriage blocks
Machine pins
Tooling components
Collars and spacers
Indoor mechanical assemblies
Benefits
Where this option can add value.
- Produces a dark steel appearance
- Adds very little dimensional buildup
- Retains machined detail
- Can be combined with oil or wax for handling protection
Limitations
Requirements that need engineering review.
- Corrosion protection is limited without a maintained seal.
- It is not the same process as black anodizing for aluminum.
- Color varies with steel composition and heat treatment.
- Oiled parts may not suit clean, adhesive, or paint-sensitive assemblies.
RFQ checklist
Finish details to include in the quotation package.
Clear requirements help engineering, finishing, inspection, and purchasing review the same target.
- 01Exact steel grade and heat treatment
- 02Black oxide process or standard
- 03Oil, wax, or dry seal requirement
- 04Cleanliness and residue limits
- 05Masked or uncoated features
- 06Corrosion exposure and packaging
Related parts
Representative geometry from the parts gallery.
Only the rail carriage is labeled black oxide in the current gallery. The other cards show related precision and tooling geometry for finish comparison.
Linear Rail Carriage Block
CNC Machining · Tool Steel · Black Oxide
View part
Injection Mold Insert
Mold Tooling · Tool Steel · Polishing
View part
Precision Turned Shafts
CNC Turning · Stainless Steel · Passivation
View part
Automation Gripper Jaw
5-Axis CNC Machining · Aluminum 7075 · Hard Anodizing
View partRelated finishes
Compare appearance, material compatibility, and functional intent.
FAQ
Black Oxide questions from engineering and sourcing teams.
Does black oxide add significant thickness?
It is a conversion treatment with minimal dimensional buildup compared with many deposited coatings, but precision parts still need a process and inspection review.
Is black oxide suitable outdoors?
It generally provides limited corrosion protection and often relies on oil or wax. Outdoor or wet exposure needs a more robust, validated protection strategy.
Can aluminum receive black oxide?
The common black oxide process described here is for ferrous materials. Aluminum dark finishes are usually addressed with black anodizing or a compatible coating.
Start your RFQ
Upload your drawings and receive an engineer-reviewed quotation.
Share the material, process, quantity, finish, critical requirements, and delivery needs. contact@kewei-kw.com / +86-13929495765