wklein
Well-Known Member
Looking at my book of breaking strengths 12mm solid 316 rod has breaking load of 5650 kg and 12mm wire (316 also) is 10400 kg. Anyone know the reason?
Wire stronger than rod?
- Thread starter wklein
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lw395
Well-Known Member
http://www.sailingservices.com/standrigging/nitronic_rod.htm
Presumably the rod figure you are using is not a rigging wire?
11mm Navtec wire comes in over 13T.
Presumably the rod figure you are using is not a rigging wire?
11mm Navtec wire comes in over 13T.
davidej
Well-Known Member
Seems a very big difference
vyv_cox
Well-Known Member
Rod will be hot drawn and normalised, so somewhat stronger than as-cast but not a lot or possible none, as austenitic steels are not hardenable by heat treatment. Wire is cold drawn through a small die that work hardens it. I believe that rigging wire is typically reduced by about 3%, which for austenitic stainless steel has a large effect. Other rigging items are cold stamped, which also strengthens them but not by so much.
smithson654
N/A
a book of breaking strengths 12mm.
blunt rods can be much stronger than those at distances greater than 1 cm over Wire stronger presumably the rod figure you are using book of breaking strengths load of 5650 kg and 12mm wire is 10400 kg.
blunt rods can be much stronger than those at distances greater than 1 cm over Wire stronger presumably the rod figure you are using book of breaking strengths load of 5650 kg and 12mm wire is 10400 kg.
haydude
Well-Known Member
Vyv is clearly the subject matter expert here but an intuitive reason is that wires are coiled and thus more flexible.
sarabande
Well-Known Member
would the different cross-sectional area have anything to do with it ? Wire rope has tiny gaps (interstices) which subtract from the overall area of a similar section of rod.
Hoolie
Well-Known Member
Obviously it has the effect of reducing cross-section, but re-read Vyv's post.
It's the tensile properties of the steel that are different. The bulk rod material can't be made as strong as drawn wire!
pvb
Well-Known Member
As lw395 has said, you're not comparing like with like. 12mm rod rigging is significantly stronger than 12mm wire rigging.
davidej
Well-Known Member
Why do racing yachts use it then? It surely cant be because the aerodynamic drag of rod is less than than wire.
I suspect the OP's figures are wrong and that rigging quality rod (which would have been drawn as well) is a good or better than the equivalent wire.
I suspect the OP's figures are wrong and that rigging quality rod (which would have been drawn as well) is a good or better than the equivalent wire.
penfold
Well-Known Member
It's exactly that; the smooth surface of the rod gives less drag than wire rope, it is also thinner than equivalent strength wire which reduces drag further and lightens the rig. Dyform is also stronger than ordinary wire and less draggy, but to a lesser extent.
Roberto
Well-Known Member
It's mainly elongation (elastic modulus): given a diameter (sectional area) and load, rod (say navtec50) will elongate less than dyform for example (the stranded rope where individual strands are shaped and closely fitted one another), which in turn elongates less than 1x19 wire rope
so if you have a racing boat, a rod standing rigging tends to preserve its dimensions better than dyform, even more with 1x19 wire
not sure it is of much interest to the average cruising yacht
wklein
Well-Known Member
This isn't a specifically boating related question, i was as i said not looking at nitronic 50 but 316. I got the initial breaking load here http://www.stalok.com/Images/pdf/Sta-Lok%20Tie%20Rod%20Brochure.pdf
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