Magnetic 316 wire

[Douglas]

Ahoy John ,,, getting good quality wire is harder than you think .

Each batch of raw wire before it is wound into 1 X 19 , can be suspect .

If you have only one outside strand showing corrosion , ( I think it is called , "Barber Pole" ) ,,, like rust corrosion , would you open up the strands to inspect the core wound wires , too , or would you assume that there may also be a corroded wire in the core windings , as well ?

I found that Barber Pole rusting effect on my 316 SS 1 X 19 rigging wire , too , but cleaning the outside with pickling paste (nitric / hydrofluoric/ phosphoric acid combos) that cleaning did not go into the core wires,,,,, eventhough the cable looked fine , ie: bright and no rust , on the outside ,,,, later I found out the inside core wires were v rusted , Ouch !

There is v good reason that knowledgable surveyors recommend to replace all SS structural fittings after 10 years , use , in warm salt water environments .

[johnamross]

The Mill Certificates from the Chinese supplier show it is 316. We are going to send off samples for chemical analysis. I guess if that comes back normal the client will have to accept it.

[Douglas]

Ahoy John ,,, the difference between 304 SS and 316 SS , is , a small amount of Molybedum (sp-?) 2% or so , is added , to reduce rust pitting of the 316 SS .

I did find on internet searches , that SS can be tested chemically , to determine if it is 304 or 316 , and that can be identified .

The test suggests to use Hydrochorlic acid drops on the SS sample ,,, as that acid reacts with the molybedum ,,, if it shows present ,,, it is 316 , if not it will most likely be 304 , which in warm water salt water environments , show rusting then pitting corrosion on your 304 SS , heaps faster than with 316 .

It is hard to find useful info on SS ,,, you have to look in many places .

I have been told that SS from China , is not always up to Mil Spec or ISO standards ,,, but that Korean SS is more reliable . The bulk of our wire comes from either place , or so I am told !

Try this website for metal testing kits : http://sfiaust.com.au/search_results...-moly-drop-960 ,,, or this one ,,,,, http://www.koslow.com/metal_test_kits/1542c.html

BTW we purchased our new 316 SS 1 X 19 , in Phuket , from an Aussie owned shop , that inported all his wire from Oz ,,,, the printing on the spool said Sta-Lok , and Arcos (from Oz) and now less than a year in Singapore , we have "barber pole" rust showing up on one outside strand , Drats !

[Brion Toss]

Hi again,
I look forward to seeing the results of those tests. Be sure to keep us posted.
Fair leads,
Brion Toss

[johnamross]

The yard (and their lawyer...) were presented with the evidence and have agreed to replace the faulty rigging regardless of the outcome of chemical testing. I will try to get the test results once they are done. Thanks for all the advice.