#27 FASTENER PLATING, COATINGS & FINISHES
Printable shop wall chart: #27 FASTENER PLATING, COATINGS & FINISHES. Free letter-size PDF to print and post at the counter; 25 x 36 inch poster version available.
Selection by environment
| Environment | Good choices | Avoid |
|---|---|---|
| Indoor, dry | Plain + oil, zinc plate, black oxide | - |
| Indoor, damp / light outdoor | Zinc plate Fe/Zn 8-12, zinc-nickel, zinc flake | Black oxide, plain |
| Outdoor, general | Hot-dip galvanized, mechanical zinc, zinc flake | Thin clear zinc |
| Coastal / marine | Stainless 316, heavy HDG, sealed zinc flake | Zinc plate, black oxide |
| High-hardness parts (HRC 39+) | Zinc flake, mechanical zinc | Electroplate without bake |
ASTM B633 service condition (zinc thickness)
| Service condition | Designation | Minimum zinc |
|---|---|---|
| SC 1 - mild (indoor, dry) | Fe/Zn 5 | 5 micrometres |
| SC 2 - moderate (indoor, some moisture) | Fe/Zn 8 | 8 micrometres |
| SC 3 - severe (outdoor, wet) | Fe/Zn 12 | 12 micrometres |
| SC 4 - very severe | Fe/Zn 25 | 25 micrometres |
ASTM B633 finish types
| Type | Finish |
|---|---|
| I | Zinc as plated, no supplementary treatment |
| II | Colored chromate (yellow, olive drab, black) - hexavalent |
| III | Colorless chromate (clear) - hexavalent |
| IV | Phosphate |
| V | Colorless passivate - trivalent |
| VI | Colored passivate - trivalent |
A finish never changes the grade, but it always changes friction and therefore torque. Electroplated parts at about HRC 39 and above need a prompt relief bake or a non-electrolytic coating.
These tables carry the same figures as the printed sheet below.
The printed sheet
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Text version of this sheet
Fastener Plating, Coatings & Finishes
CLEAR ZINC
YELLOW ZINC
BLACK
HOT-DIP GALV
ZINC FLAKE
Choosing a finish · environment, thickness and hydrogen-embrittlement risk
Selection by environment
Environment
Good choices
Avoid
Indoor, dry
Plain + oil, zinc plate, black oxide
-
Indoor, damp / light outdoor
Zinc plate Fe/Zn 8-12, zinc-nickel, zinc flake
Black oxide, plain
Outdoor, general
Hot-dip galvanized, mechanical zinc, zinc flake
Thin clear zinc
Coastal / marine
Stainless 316, heavy HDG, sealed zinc flake
Zinc plate, black oxide
High-hardness parts (HRC 39+)
Zinc flake, mechanical zinc
Electroplate without bake
ASTM B633 service condition (zinc thickness)
Service condition
Designation
Minimum zinc
SC 1 - mild (indoor, dry)
Fe/Zn 5
5 micrometres
SC 2 - moderate (indoor, some moisture)
Fe/Zn 8
8 micrometres
SC 3 - severe (outdoor, wet)
Fe/Zn 12
12 micrometres
SC 4 - very severe
Fe/Zn 25
25 micrometres
ASTM B633 finish types
Type
Finish
I
Zinc as plated, no supplementary treatment
II
Colored chromate (yellow, olive drab, black) - hexavalent
III
Colorless chromate (clear) - hexavalent
IV
Phosphate
V
Colorless passivate - trivalent
VI
Colored passivate - trivalent
A finish never changes the grade, but it always changes friction and therefore torque. Electroplated parts at about HRC 39 and above need a prompt relief bake or a non-electrolytic coating.
The Fastener App | TheFastenerApp.com
Fastener Guide reference FG-A21288 · thefastenerapp.com/fastener-guide/wall-charts/27-fastener-plating-coatings-and-finishes · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
