Bob C
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| posted on 24/1/09 at 06:08 PM |
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Working REALLY hard steel...
Hi All,
I'm trying to adapt some of the hub splied driveshafts for a different application. Now the material seems to be incredibly hard - if I actually
get a cut going with a (new sharp) carbide tool the swarf comes off bright orange/white hot & the whole process does not seem to be doing the
lathe any favours.
When I've done the turning I want to weld (probably MIG) to a hooke joint. I have a feeling that this ain't ever going to work - if I do
successfully shape the hub with an angle grinder in the lathe (covering the lathe in carborundum in the process) I suspect the weld will just snap off
if you look at it funny... Anybody got any experience with this stuff?
Thanks
Bob
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flak monkey
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| posted on 24/1/09 at 06:46 PM |
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The ends of the driveshafts are hardened, you dont stand a chance of turning it with carbide tools. The only thing that will cut hardened steel is
either CBN or ceramic tips, both of which need an incredibly stiff machine to do it properly. We do a LOT of hard turning at work and some of what we
do amazes even the tip manufactuers (e.g 70 minute interrupted cuts on bearing inner races at 62Rc which we were told was impossible....)
It depends on the exact type of steel whether you will be able to weld it. If its a relativly low carbon steel, which it probably is, its
hardenability will not be very good so you might stand a chance. If it is a hardenable steel the it will be a pig to weld. If it cools too quick the
material will effectively quench and harden and likely crack too.
David
Sera
http://www.motosera.com
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DavidM
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| posted on 24/1/09 at 06:56 PM |
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In relation to MIG welding it, unless you know the grade of material and the method of heat treatment, it will almost certainly crack during or after
welding.
David
Proportion is Everything
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Bob C
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| posted on 24/1/09 at 08:07 PM |
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Thanks Dave & Dave, you've sort of confirmed my suspicions. So I think I'll have to find another way: shame 'cos that would have
been nice and easy. I'll get some fresh driveshafts made of EN24 & weld them on. I'll have to engineer it so that the weld is not also
holding the wheel on too!!! a driveshaft snapping is a bit of an issue but not so bad as a wheel falling off ;^)
PS It wasn't particularly high carbon from the grinder sparks. Moon metal I guess.....
PPS it's an outer CV joint housing I'm trying to machine
[Edited on 24/1/09 by Bob C]
[Edited on 24/1/09 by Bob C]
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