Allowable stresses for plated springs

[Philrock]

Are there rules of thumb for additional safety factors or reduced allowable stresses for helical coil round wire compression springs with the following finishes?

zinc electroplating
zinc mechanical finish
gold iridite
passivation

Thanks,
Phil

 

[israelkk]

If the plating is correctly done according to specification such as ASTM, MIL-STDs, AMS, etc. there is no strength reduction of the wire at all. If hydrogen embrittlement is omitted or not done properly when it is required, the spring may break or crack and such spring should be discarded. There is no safety factor that can compensate for it.