Galvanic Reaction
Galvanic Reaction
(OP)
Hi all,
We have an electrified monorail conveyor where the rail is aluminum and is suspended with "C" hooks made of steel. The suspension method is that the "C" hooks have a HRS plate which is bolted to the 3/8" thick web of the aluminum rail.
Traditionaly, our protection against galvanic reaction was to paint the the "C" hooks so that we had at least a film of paint between the steel and the aluminum. Stainless bolts were used to minimize the reaction at the holes.
The problem is, during a rework of the conveyor, the contractor installed the "C" hooks unpainted and there is no time to rectify this before plant start up.
My concern is, that in a humid environment during the summer months, how long could the situation remain before the structural integrity of the aluminum rail is compromised due to corrosion.
Thanks in advance for all opinions and advice.
We have an electrified monorail conveyor where the rail is aluminum and is suspended with "C" hooks made of steel. The suspension method is that the "C" hooks have a HRS plate which is bolted to the 3/8" thick web of the aluminum rail.
Traditionaly, our protection against galvanic reaction was to paint the the "C" hooks so that we had at least a film of paint between the steel and the aluminum. Stainless bolts were used to minimize the reaction at the holes.
The problem is, during a rework of the conveyor, the contractor installed the "C" hooks unpainted and there is no time to rectify this before plant start up.
My concern is, that in a humid environment during the summer months, how long could the situation remain before the structural integrity of the aluminum rail is compromised due to corrosion.
Thanks in advance for all opinions and advice.





RE: Galvanic Reaction
Why do you think the use of SS bolts helps? They probably are strong cathodes. I think you're lucky their total area is small.
RE: Galvanic Reaction
For peace of mind, for a cheap and cherful solution you might consider placing a strip of electrical insulation paper between the steel and aluminium surfaces. They are dry and you won't have to paint them unless UV is a problem but you can do that insitu. Won't affect their insulation properties.
Nomex, Mylar, or Pyrolam are candidate materials. All have di-electric strengths of 300v/mil or better and compressive strengths sufficient to easily carry the load. You will need to check this out though. I reckon about 15 mil should do it.
RE: Galvanic Reaction
RE: Galvanic Reaction
RE: Galvanic Reaction
Haggis
RE: Galvanic Reaction