Met Blue Fasteners 3

[rotta]

Can someone define what determines a Met Blue fastener?

 

[mcgyvr]

metallic and colored blue?
Color matched to the New York Mets blue?
Color matched to MetLife blue?

 

[CoryPad]

I believe this is a reference to Metric Blue fasteners, which were popular in the USA about 15 years ago as conversion to SI was gaining popularity in certain industries. The fasteners had a blue coating to make them distinctive compared with standard black oxide or electroplated zinc fasteners.

 

[mcgyvr]

yes that slipped my mind (it's in a big knot today)... Metric blue fasteners are still widely available.

 

[rotta]

so there are no material properties etc that would differentiate metblue fasteners from the commercially available ones? i have an injection molding machine which is using these and couldn't find anything special about them. I am assuming i can substituew with a black oxide and be ok.

 

[CoryPad]

The coating on original Metric Blue fasteners had lower friction coefficient than black oxide or electroplated zinc. Current metric fasteners with blue coating may or may not have this feature.

 

[unclesyd]

The generic Metric Blue coating was just a dyed electrozinc coating which was used only for identification and offered no friction or corrosion advantage.
The normal call out now is for "yellow zinc" on all zinc coated fasteners. This is a chromate conversion coating for corrosion resistance.
There is a blue coating that was/is used on 1/2" and larger fasteners of all types for corrosion resistance. This is a Blue Teflon or Blue Xylan coating.

 

[ornerynorsk]

Some of the blue coatings are an organic polymer to reduce hydrogen embrittlement risk.