Selecting correct tube grade - live rear axle housing
Selecting correct tube grade - live rear axle housing
(OP)
Hi there, I'm after some guidance with regards to selecting the correct grade of steel tube for a particular job, please.
(Hoping this is the right forum section?)
I'm fabricating a live rear axle housing for use in an off-road application, and I'm getting confused by all the different grades of tube available.
The axle tube will be under constant (and sometimes severe) bending loads. It also needs to be weldable, and machinable. I'm not interested in surface finish - and to be honest - dimensional accuracy is not too important as the tube will be turned/skimmed where size is critical.
The big tube suppliers seem to stock 2 common grades, in the required size;
Cold drawn seamless - EN10305-1 E235+c
Hot finished seamless EN10297 E355+AR/S355J2H
Now people keep advising me that the CDS will be stronger, as the cold-forming will work harden it, but according to the spec sheets - the HFS is slightly stronger (550MPa compared to 470MPa min UTS) But the HFS elongation figure is 22% whereas the CDS figure is 16%.
And how do I know which will be better in "impact"?
There are other, more exotic grades of tube available - 4130 for example - but I'm worried about the practicalities of welding this (and the PWHT) not to mention the cost.
15CDV6 looks superb - but V expensive - and i'd have to have it made in my required size, minimum order quantity makes it unreasonable.
Any suggestions or words of wisdom would be much appreciated,
many thanks
John.
(Hoping this is the right forum section?)
I'm fabricating a live rear axle housing for use in an off-road application, and I'm getting confused by all the different grades of tube available.
The axle tube will be under constant (and sometimes severe) bending loads. It also needs to be weldable, and machinable. I'm not interested in surface finish - and to be honest - dimensional accuracy is not too important as the tube will be turned/skimmed where size is critical.
The big tube suppliers seem to stock 2 common grades, in the required size;
Cold drawn seamless - EN10305-1 E235+c
Hot finished seamless EN10297 E355+AR/S355J2H
Now people keep advising me that the CDS will be stronger, as the cold-forming will work harden it, but according to the spec sheets - the HFS is slightly stronger (550MPa compared to 470MPa min UTS) But the HFS elongation figure is 22% whereas the CDS figure is 16%.
And how do I know which will be better in "impact"?
There are other, more exotic grades of tube available - 4130 for example - but I'm worried about the practicalities of welding this (and the PWHT) not to mention the cost.
15CDV6 looks superb - but V expensive - and i'd have to have it made in my required size, minimum order quantity makes it unreasonable.
Any suggestions or words of wisdom would be much appreciated,
many thanks
John.





RE: Selecting correct tube grade - live rear axle housing
High flex mod and high elongation will be your friend if this is really off road as opposed to on track as in drag or circuit.
Regards
Pat
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RE: Selecting correct tube grade - live rear axle housing
If you're only making one or a few, were I you, I'd scour junkyards for raw material.
Or just order a special from Currie or someone else who's already tooled up to make this stuff at a competitive price.
Mike Halloran
Pembroke Pines, FL, USA
RE: Selecting correct tube grade - live rear axle housing
Thanks again.
RE: Selecting correct tube grade - live rear axle housing
RE: Selecting correct tube grade - live rear axle housing
Is there a good source of info/data on all the different grades, designations, suffixes and properties etc that you would recommend?
Thanks again.
RE: Selecting correct tube grade - live rear axle housing
h
http://www.nationaltube.co.uk/pdf/Hydraulic_1.pdf
http:
RE: Selecting correct tube grade - live rear axle housing
Axle housings fail to perform their intended function when they deform enough to damage the gears and bearings within.
That happens long before they reach ultimate tensile strength, and before they reach yield strength, too.
You should be looking at deflection under the set of applied loads. ... which is more sensitive to geometry than to material properties.
Mike Halloran
Pembroke Pines, FL, USA
RE: Selecting correct tube grade - live rear axle housing
Good points all, but round tube axles for severe off-road use nearly always have additional support structure added.