Has anyone sucsessfully bend any of the 25 RHS which we use to build our chassis from? If so, how?
Cheers,
The Baron
Yes, between three rollers in a cast machine !
Not a lot of use without the machine I,m afraid.
Have to ask why? Any bits that need bending in 1" will curve in on the outer edge. Surely round tube would be better?
heating with a borrowed oxy set will work just bend round an steal pipe.
It will fold in if it isnt bent properly. Why do u need to do it? Id cut an angle out of it, bend it and weld it up.
heating it will make it brital
quote:
Originally posted by goodall
heating it will make it brital
Actually, heating will make it soft!
Rapid cooling (quenching) will make it harden.
quote:
Originally posted by goodall
heating it will make it brital
Overheating will make it brittle. I would recommend forming the bends on a set of rolls like Mark Chandler did, or having them formed using proper formers to avoid the swelling as allured to by Simon, although battering with a big hammer can cure the swelling problem. Somebody will probably tell you to then have the whole thing stress relieved, but I wouldn't bother. What's it for anyway?
quote:
Originally posted by goodall
heating it will make it brital
something like this?
http://www.metalgeek.com/archives/images/deform_jig.jpg
Alex
Actually heating won't make it soft or brittle --- heating and cooling low carbon mild steel has virtually no effect on either -- thats why
it is the material of choice welded chassis.
However if you keep mild steel very hot for an extended period followed slow cool you will get grain growth -- which reduces the fatigue resistance
and generally lowers the mechanical properties.
To refine the grains you have to get the whole part very very hot then cool quickly, which won't have much if any hardening effect on low carbon
mild steel.
High carbon steels on the other hand are a whole different ball game.
[Edited on 4/1/07 by britishtrident]
I think commercial chassis with bends are designed that way for production reasons - a spaceframe should be made of straight sided triangles!
Bob
PS they'll be done cold...
[Edited on 4/1/07 by Bob C]
quote:
Originally posted by britishtrident
Actually heating won't make it soft or brittle --- heating and cooling low carbon mild steel has virtually no effect on either -- thats why it is the material of choice welded chassis.
However if you keep mild steel very hot for an extended period followed slow cool you will get grain growth -- which reduces the fatigue resistance and generally lowers the mechanical properties.
To refine the grains you have to get the whole part very very hot then cool quickly, which won't have much if any hardening effect on low carbon mild steel.
High carbon steels on the other hand are a whole different ball game.
[Edited on 4/1/07 by britishtrident]
Heating it up to bend it and heating it up to weld are different things though, welding is done in a controlled atmosphere to reduce oxidation and contamination, that's why I warned against overheating it to bend it. Cold forming with the proper formers is better.