Manganese Phosphating (High-Temperature)
Manganese phosphating: a porous crystalline layer that holds oil, giving 24-72 h protection and a good running-in surface for moving parts.
| Finish Code | TZ008 |
|---|---|
| Environmental Grade | Conventional phosphating; compatible with subsequent oiling or painting |
| Salt Spray Standard | 24-72 h after oil dipping; dry indoor service |
| Appearance / Colour | Dark grey to black crystalline |
| Suitable For | Screws subject to friction, springs, transmission parts and steel fasteners |
| Features | Corrosion resistant; oil-retentive; anti-galling |
| Environmental Compliance | REACH and RoHS compliant |
Overview
Surface finishing on a fastener is a functional coating, not a cosmetic one: it sets the friction coefficient that determines how much of the applied torque becomes clamp load, and it defines how long the part survives in a corrosive environment. Two finishes that look identical can differ by a factor of several in salt-spray hours and by enough in friction to change the torque specification. This listing: finish code TZ008, salt spray 24-72 h after oil dipping, appearance / colour Dark grey to black crystalline, environmental compliance REACH and RoHS compliant.
Advantages
Hydrogen embrittlement risk separates processes: electroplating on high-strength steel needs a de-embrittlement bake, while mechanical and flake coatings avoid the risk entirely.
Friction coefficient changes with coating: a zinc-flake coating typically runs lower and more consistently than electroplated zinc, which is why torque tables are finish-specific.
Barrier coatings protect the base metal, while sacrificial coatings protect the steel even at a scratch; the choice depends on whether the joint will be damaged in service.
Applications
Automotive underhood and body joints, outdoor equipment, marine and coastal installations, electronics hardware, and any joint where the torque specification is tied to a friction value.
Quote the standard, the hours and the acceptance criterion together — a salt-spray figure without the test method is not a specification. Check that the coating process is compatible with the core hardness of the part.
Product information is supplied by Toprecision. Custom parts can be produced to drawing — contact us for samples or a quotation.
FAQ
What does this finish provide?
Finish Code TZ008, Environmental Grade Conventional phosphating, Salt Spray Standard 24-72 h after oil dipping, Appearance / Colour Dark grey to black crystalline.
How does it affect torque and friction?
Carbon Steel.
What should I verify before ordering or installing it?
Quote the standard, the hours and the acceptance criterion together — a salt-spray figure without the test method is not a specification. Check that the coating process is compatible with the core hardness of the part.