Stainless 316 1x19 wire corrosion?

[Snowpetrel]

Originally Posted by td0tz

All this sounds like more reason to go Dyneema.

Or Galvanised...

[maxingout]

The broken strands are mostly at the top, but not always. I think it is vibration related as the mast works at sea. The broken strands are never at the swages.

[Bleemus]

"The broken strands are never at the swages."

Nope, never.

[jhulmer]

I work with a lot of stainless in my day job and would point out another possibility.
If this is new rigging it is possible that when the riggers made up the wire it was dragged over a carbon steel table or equipment dies. The way it is on the outer surfaces forms my suspicions.

I have seen this happen a lot to our products. It doesn't show up until it is exposed to the elements.

So the suggestions made earlier to passivate (or pickle) is what we do.

I use this for welds and areas worked with carbon steel tooling:
https://www.mcmaster.com/#8554t11/=1993bhv

You can usually find a similar product at good welding suppliers.

[Captsteve53]

Originally Posted by maxingout

The broken strands are mostly at the top, but not always. I think it is vibration related as the mast works at sea. The broken strands are never at the swages.

Strange!, In my 40 odd years of rigging experience i have found 80% of failures at the lower swage fittings due to:

The stainless swage and wire is work hardened at that point due to the compression/cold working factor combined with continual corrosion factors/ingress of salt water /warm-hot air leads to the death bell! caused by Stress corrosion cracking/pitting corrosion/crevice corrosion,

Cheers Steve (MIIMS-Lloyd's Maritime)

[DumnMad]

Originally Posted by maxingout

Our boat is 24 years old, and we have replaced rigging whenever there was a broken strand of wire.

We found that the 8mm and 10 mm wire that maintain the mast in column on our Privilege 39 catamaran require frequent replacement. When the boat was a year old, we had to replace a wire in Bora Bora because of a broken strand. So far I have replaced 8mm and 10 mm wire in Bora Bora, Fiji, New Zealand, and Australia. The 12 mm headstay was 12 years old when replaced in Gibraltar because of a broken strand.

The 12 mm Cap shrouds/backstays are 24 years old and have never broken a strand of wire or required replacement. The cap shrouds were backed up by running backstays which may have protected the cap shrouds to some degree.

We never had a problem with corrosion in our rigging or swages. It was always a failed strand of wire that forced replacement of a piece of rigging. I think it was vibration that caused the 8mm and 10 mm wires to break strands.

My standard operating procedure now is that when I arrive in a new port, I climb the mast and inspect the wire for any broken strands. That way I have plenty of time to deal with the issue before heading for the next destination.

Corrosion has never been a problem. Broken strands are my nemesis for the past 24 years.

I've read somewhere that smaller diameter wire is less ductile which would partially explain your experience. So 8mm = less ductile & more highly stressed, and in a more salty & warmer climate = more frequent breakages.
Go up a size or get a mono

[Captsteve53]

Originally Posted by DumnMad

I've read somewhere that smaller diameter wire is less ductile which would partially explain your experience. So 8mm = less ductile & more highly stressed, and in a more salty & warmer climate = more frequent breakages.
Go up a size or get a mono

Maxingout

I can see why you never have an corrosion issue as it looks like your change out schedule would never allow time for corrosion to set in!

Would like to know if the is standard 1 x 19 SS wire and if you have considered changing to DYFORM wire as for the same size in conventional 1 x 19 Dyform is up to 30% stronger with less stretch as well, also much smoother,

Dumnad

What you say has some fact as:The Modulus of Elasticity also varies with different rope constructions, but generally increases as the cross- sectional area of steel increases.How ever the actual measurable difference between say 8 mm or 12 mm is minimal

Cheers Steve

[Cheechako]

I havent seen a large amount of broken strands, but he ones I have seen are often near the bottom fittings. It makes perfect sense though that the break often is near a fitting.... wherever it is... the fitting is a hard point, the stress in the sire is higher there. Put a coat hanger in a vice and bend it back and forth, it breaks at the vice. Not to mention the corrosion accumulation at the fitting interface.