There's a lot of literature about these 2 metals being in contact with possible galvanic corrosion. However I can't find any specific reference to the situation in my question.
Given the limited contact area of cable ties with a cable tray, should I be worried to accept stainless steel cable ties being used on HDG cable tray?
Only worry, I suggest, if you expect it to get wet. Certainly time to failure will be measured in years and no worse than cable fixings of mild steel band of the same thickness,
Mike
Hello Mike:
Based on stainless steel wire used in my kitchen sink draining unit, there seems to be a wide range of Stainless Steels being sold.
Some is very corrosion resistant and some is not.
I have seen the same thing with safety bars used in bathroom showers.
Peter Brooks
Palm Bay Florida
The good cable ties are normally alloy 316 - which has molybdenum as the inhibitor and is actually pretty good, as well as being reasonable to weld, tthough I agree there are some un-numbered stainless steels that barely qualify for the title.
The part that will corrode if wet will be the zinc, where the stainless band and the tray meet, but even once the zinc has corroded through, to rust the tray to failure will take years.
Mike
Presumably you could use s/steel ties with a plastic sleeve or coating, so there'd be no direct metal-metal contact in normal service?
- Andy.
Is 316 flexible enough for something like a cable tie? I would expect something from the 400 series of stainless steels? I recently came across a handy table for fastener compatibility - I suppose I can't really paste it here for copyright reasons, but it's freely available on the last page of a PDF: "Stainless Steel Fasteners - A systematic approach to their selection, a designers' handbook series N O 9003" - on the Nickel Institute website... "table 10 – guidelines for selection of fasteners based on galvanic action"...
For this case either type of stainless fastener with galvanised steel base metal is described in that table as "The corrosion of the base metal may be markedly increased by the fastener material.".
As has been said elsewhere on this thread, only likely to be an issue at high humidities or when liquid water is present (and could be accelerated by air pollution or salt spray), and something like a bit of EPDM to isolate the two materials would put a stop to the issue.
Things like cable ties certainly can be made of stainless 316, and the good (well, expensive anyways) ones are - or at least that what the packet says..
Actually, I see they are also available with a dielectric coating, presumably in part for this reason, and perhaps also to cushion whatever is being gripped.
Example
https://cableties.co.uk/products/coated-stainless-steel-cable-ties
That may be a neat way out
Mike.
Might be worth speaking to the manufacture of the hot dip galvanised tray and ask them do they have the same material for cable clips? Normally it is better to use the same material for the tray and clip as this will reduce corrosion depending on the enviroment. GRP tray may also be another option have a look at marshall-tufflex (other brands are available)
GRP tray may also be another option
Given that the use of metal ties is usually driven by the need to prevent premature collapse in the case of fire, selecting a plastic tray might be a bit counter productive?
- Andy.
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