ERW / Seamless Tube

[Ewok]

Sorry to be thick but...

Is seamless tube sugnificantly stronger than ERW? Is the seamless more difficult to bend?

I have some motorcycle tow frames to make out of 3/4" tube and want to buy the right stuff !

 

[fingers99]

Significant enough in that application, I'd think. Should be just as easy/difficult to bend, perhaps easier.

 

[Ewok]

Thank you. Good to have a second opinion. Just done a bit more digging myself - and unless under extreme conditions - to all intense and purposes for me ERW and seamless would perform the same - but obviously ERW will be less expensive.

 

[pedrobedro]

ERW is perfectly adequate for anything automotive as long as you get the right wall thickness. CDS or seamless is overkill for anything less than roll bar construction where the regulations demand it.

 

[Ewok]

Great. Thank you.

 

[asmeix6g]

pedrobedro, CDS is far superior! roll cage etc ok but also motorbike frames and anything thats going to be under huge amounts of stress. i always found T45 the best to work with

 

[hotrodder]

Obviously depends on regs (if they're are any) but it's fairly typical to use a thinner wall when using 'better' materials i.e. you save weight rather than end up with something stronger.

 

[Ewok]

Better being seamless?

 

[hotrodder]

Sorry 'better' didn't really mean anything there, was just pointing out that when stronger materials are used it's often to save weight rather than because the cheaper stuff isn't strong enough. If weight isn't an issue then ERW is often better (cost)

Specs for ERW, CDS(CFS) and DOM(CEW) are here. All three are available 'as welded/drawn' normalised and annealed which effects mechanical properties and how it bends. 'Blackwolf' has made several fairly in depth posts on how this effects bendability, be worth searching for those. Kinking won't really be an issue for the small diameter stuff you're talking about.

 

[Ewok]

Thank you - I'll go and do some digging and educate myself

 

[pedrobedro]

pedrobedro, CDS is far superior! roll cage etc ok but also motorbike frames and anything thats going to be under huge amounts of stress. i always found T45 the best to work with

I didn't say it wasn't did I ? You can't just mig T45 though and it costs ten times as much. If you choose the right ERW material it is perfectly adequate and if you get the wrong CDS you can be worse off as it is available in different temper for different purposes like hydraulic cylinders which is designed not to bend.