Corrosion Resistance

[engiNERD77]

I have a hex shaped fixture that is plugged into an adaptor. The fixture is made of 4140 ph. I originally had no coating and became concerned with rusting. The second design had a black oxide coating but is quickly wearing off. Could I get some ideas of the cost difference with maybe a chrome plating and dimensional changes I could expect? Or possibly some other application that would help resist the tendency to rust. Thanks.

 

[0707]

if it to work at ambiente temperature, use some kind of teflon tape. If it is going to be used in hot work maybe a molycote lubrificator could be useful.