What do you think this spring is made from?

[Tim Good]

This spring is for poling out two headsails. In each end a male pole fitting screws. Then each pole is attached to the spring and to the clews of the sails. I.e. A Twizzle Rig.

On a passage back from the Azores it got bent. As per picture. I want to get another made. There are plenty of specialist spring companies but they need to know the exact material. Is it likely to be 316 stainless or some other alloy?

 

[cherod]

stick a magnet on it , 316 A4 is non magnetic, A2 is a little

 

[rogerthebodger]

I does not look like stainless steel rod and 316 or 304 doesn't make very food springs.

As said stick a magnet on it

 

[Tim Good]

I does not look like stainless steel rod and 316 or 304 doesn't make very food springs.

As said stick a magnet on it

What could it be if not stainless? It doesn’t appear to rust at all.

 

[cherod]

has to be , looks like s/s , better hope it is not titanium !!

 

[HissyFit]

By the surface finish and the fact that it is a spring, I would hazard a guess at music wire. Used to be specified under BS5216 when I was using the stuff.

 

[rogerthebodger]

What could it be if not stainless? It doesn’t appear to rust at all.

Thats a good question.

I use quite a lot of stainless rod, mainly drawn rod and it quite a different colour.

The magnetic test would give some indication.

BTW stainless steel does rust if not polished and even then can have spots of rust on the surface. Thats why its call stain less not stain free.

 

[vyv_cox]

There are many grades of stainless steel. I would guess that this is a martensitic grade to give it sufficient hardness for a spring together with reasonable corrosion resistance. I guess that 420 is the most probable but it would require heat treatment. Try a simple hardness test: cut it with a hacksaw. If it cuts easily it is probably softer than about 400 Vickers, so probably oil quench at 960, temper at 700 C. If it is pretty hard work with the saw tending to skid , probably oil quench at 960, temper at 400 C.

Martensitic SS would be attracted to a magnet. Knife blades are often made from it.

 

[Tim Good]

There are many grades of stainless steel. I would guess that this is a martensitic grade to give it sufficient hardness for a spring together with reasonable corrosion resistance. I guess that 420 is the most probable but it would require heat treatment. Try a simple hardness test: cut it with a hacksaw. If it cuts easily it is probably softer than about 400 Vickers, so probably oil quench at 960, temper at 700 C. If it is pretty hard work with the saw tending to skid , probably oil quench at 960, temper at 400 C.

Martensitic SS would be attracted to a magnet. Knife blades are often made from it.

Can always trust you for a solid answer, VYV!

Do you think the spring I have actually got can be repaired or once they bent out of shape like that do you think that’s it?

 

[sarabande]

Genuine question. Would a stainless spring of that wire thickness work harden in use ?

 

[cherod]

There are many grades of stainless steel. I would guess that this is a martensitic grade to give it sufficient hardness for a spring together with reasonable corrosion resistance. I guess that 420 is the most probable but it would require heat treatment. Try a simple hardness test: cut it with a hacksaw. If it cuts easily it is probably softer than about 400 Vickers, so probably oil quench at 960, temper at 700 C. If it is pretty hard work with the saw tending to skid , probably oil quench at 960,

That could be fun ?

 

[Iliade]

It could be Nitinol. It certainly looks like it.
If it is and you are really lucky just pop in into boiling water and it should return to its proper shape.

 

[TernVI]

It bent when you used it.
Why do you want another one the same?

 

[cherod]

It bent when you used it.
Why do you want another one the same?

maybe because it has performed admirably for 25 years and he reckons another one will do the same,,,, just saying

 

[vyv_cox]

Genuine question. Would a stainless spring of that wire thickness work harden in use ?

All metals work harden, as far as I know. but 'work' in this context means plastic deformation, not the normal elastic deformation that springs are designed to accommodate.

Why anyone would select an expensive and specialised alloy like Nitinol for a job like this would need some justification.

 

[Tim Good]

It bent when you used it.
Why do you want another one the same?

Because the system is flawed. My poles appear too long for the sails and the inner forestay meant too much tension on the downhaul. Throw in some tough weather on the tail of storm Ellen and you get a bent spring. I feel it is fine if used correctly.

 

[Tim Good]

It could be Nitinol. It certainly looks like it.
If it is and you are really lucky just pop in into boiling water and it should return to its proper shape.

Interesting. You'll get big bonus points if that works!