TVP,
Thanks for your input. I got a hold of the ASM handbook and it is certainly the best source of information on the subject I could find.
Just to add to the discussion - through my research on this topic I came across some documented cases of Cadmium plated bolts and aluminium compressed air...
I am seeking a clarification regarding galvanised steel and the effects of SMIE.
According to ASTM A193 - Paraphrase - Galvanised Bolting should not be used when operating above half the melting point of zinc.
Can anyone provide guidance or a reference to a standard that mentions SMIE in steel...
Perhaps your manager had in mind the double expanding gate valve type. Somewhat similar to the parallel slide however the slab is split in two parts, each with a v-shape wedge like profile. When one part of the gate meets the end-stop the profile forces the "slabs" outwards achieving a seal...