High temperature stainless steel tube with thin wall 1

[asimpson]

I am finding it difficult to source 309 or 310 stainless steel tube with wall thickness less than 1.5mm (0.059") for outside diameter 15-22mm (0.56-0.866")

Used in a high temperature application (800C) formed into coils. Environment is low pressure steam and air.

So far I have only found schedule 40 pipe which is too heavy to be bent into coils.

I have done preliminary work with 316 ss to prove priciple but difficulty was cracking in the pipe.

Anybody know of source of 309 or 310 thin walled tube?


Many thanks

 

[stanweld]

Have you considered 321 and 347H as alternatives?

 

[asimpson]

Problem seems to be getting tube in 316 or 304 off the shelf is no problem. Anything else is a special production run which would be in tonnes farher than a few lengths.

Unless there is existing industry demand such as exhaust pipes which dosnt go below 1". I need less than 3/4.

I'm sure ther is some out there. Finding it is a problem.

Thanks

 

[ornerynorsk]

Not knowing your specific application, I can only say that generally tubing is easier to bend with greater wall thickness. It prevents excessive deformation, thinning, and cracking. Just a thought.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[asimpson]

I would imagine thicker walls would enhance the structural integrity of tube when it is bent however it also increases the forces to bend tube.

In any case the vendor I have been using to make up coils puts a limit of 1.5mm wall thickness for the coils I need. I am not sure of their process but so far I have been satisfied with their work.

Another vendor may be capable of coiling thick wall tube but so far I have not had any luck.

Coils are 230 mm dia. with a 19 mm o.d. tube.

 

[moltenmetal]

321 is easy to find off the shelf. 347 less so. The H grades are hard to find.

Never looked for 309 or 310 but 5/8" tubing should be available.

Alloy 600 definitely is available and might be worth considering too.

There are re-draw operations out there who will draw down larger tubes- usually for a hefty price and for a minimum order in the hundreds of feet.

 

[1gibson]

Try McMaster.com ?

You can get .028" wall 316 and 304 from 5/8" down to 1/16". Plenty of other wall thicknesses also, but sizes can get scarce.

 

[XL83NL]

310(S) is readily available here (NL) in tube form, but 321 is harder to get, opposed to USA/CA maybe (as moltenmetal indicated).
I believe each continent has it's own 'typicals' (the germans e.g. may easily supply you 316Ti, which alomost equals 321).
For piping, 321 usually comes in dual certified 321/321H, Id reckon that may be the case too for tubing, but you'd have to check. We usually get 321 tubes from the American continent.

 

[moltenmetal]

How do you dual certify something as 321/321H? It either has high carbon, or it doesn't...is there something weird in this spec? Does the H mean something other than high carbon for creep resistance? I'd often wondered how that worked with a Ti stabilized grade.

316/316L dual certified, because you can have the strength of the normal carbon grade while still meeting the low carbon spec., but you can't have 316/316H dual certified.

You're right about the regional variations in material- 316Ti is impossible to find here.

 

[cloa]

http://www.johnsontube.com/alloy/316.html

You can have 316/316H dual certified- 316H is definitely higher carbon than 316L but more so it has defined properties that need to be met as much as 316 just overlaps those properties.

 

[XL83NL]

Dual certified 321/321H is readily available for pipe [ASTM A312] and fittings [ASTM A403] (I think almost standard like 316/316L).
Flanges are more difficult to obtain in 321/321H, but Ive seen them on a recent job.
Tube I dont know of, but reviewing e.g. A213 I dont see how they cant be dual certified, from a chemical composition point of view