B.O.
Zinc
Why is zinc 50% more expensive? Which has better corrosion resistance?
Zinc
Why is zinc 50% more expensive? Which has better corrosion resistance?
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Difference between black oxide and zinc plated hardware?
- Thread starter atikovi
- Start date
Not knowing anything about your application, I would go with zinc plated.
When I installed the SLP TPI intake runners on the IROC, they came supplied with black oxide SHCS. Took no time before these fasteners became horrible corroded (mostly cosmetic) from what ever moisture was in the atmosphere under the hood. Oddly, the black oxide fasteners GM installed on the lower intake have yet to become corroded. I'm thinking the black oxide coatings on each were applied with a different process.
When I upgraded the injectors, I replaced the corroded fasteners with 316 stainless fasteners.
When I installed the SLP TPI intake runners on the IROC, they came supplied with black oxide SHCS. Took no time before these fasteners became horrible corroded (mostly cosmetic) from what ever moisture was in the atmosphere under the hood. Oddly, the black oxide fasteners GM installed on the lower intake have yet to become corroded. I'm thinking the black oxide coatings on each were applied with a different process.
When I upgraded the injectors, I replaced the corroded fasteners with 316 stainless fasteners.
Black oxide has minimal corrosion resistance. It mostly exists to prevent galling and cosmetic reasons.
Zinc has a higher corrosion resistance.
Cost is just because BO is cheaper to make than electro plating zinc
www.fastenal.com
Zinc has a higher corrosion resistance.
Cost is just because BO is cheaper to make than electro plating zinc
Finish | Fastenal
www.fastenal.com
The Zinc plated should be more corrosion resistant and is normally recommended if it will be in contact with pressure treated wood. The problem is that the zinc coated use to be about 10% more than the black but the price of metals (copper, lead, zinc) has gone through the roof. Compare Black pipe to Galvanized pipe in the plumbing dept.
Granger prices are weird like that some Times.
OK zinc it is. They also have this cheaper zinc called Class 4.8. Whats the difference between this and the other zinc called Grade 2?
Sae strength is in grade
Metric strength is class
Both the higher the number the stronger the bolt
Most Common ones are grade 2, 5, and 8 which are equivalent to 4, 8.8. 10.9. metric 12.9 is also pretty common and stronger than grade 8
Understanding Fastener Grades and Classes - Fastener Mart
Not all fasteners are created equally--some are stronger than others. This article looks at the different strength grades for both inch and metric sizes.
www.fastenermart.com
Zinc coated are not very durable long term, cadmium plating is more durable and corrosion resistant, they are commonly used as a replacement under the car in high salt areas.
Both are metric. M14-2.0
Thread size and strength are separate measurements so there is no reason a manufacturer can't mix and match.
Sae grade is measured in PSI
Metric class is measured in MPa
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