indykid
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| posted on 4/4/10 at 12:08 AM |
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10mm throat butt weld
i know there are a few pro welders on here so my question is if someone said i want a 10mm throat butt weld on a lump added onto a 32mm bar, would you
laugh at them, or would you just get on with it?
detail behind the question's in the next post
cheers
tom
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indykid
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| posted on 4/4/10 at 12:10 AM |
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a part of my final year project, i've been working on the design of a drop weight impact rig for the testing of composite materials.
dissertation's due in next monday but i'm just working through my final designs of the bits that aren't to be machined yet.
i've been doing a weld stress calc on the safety stop which is a 32mm dia en8 bar with a 27mm wide lump of en3a welded onto it.
when the sled falls from 2.5m, max drop height, assuming the 29kg sled's brought to rest in 6milliseconds on a pair of bullet shaped bump stops,
the calc suggests i need a 10mm throat butt weld all round.
is that....possible? i imagine it needs more than one pass but we have 250amp mig and a monster stick kit in uni. i don't have to actually weld
it but it'd be nice to come up with a design that's actually feasible.
it will leave an unwelded section on the back face but it's not going to be subjected to any real cyclic load. it will possibly be impacted once
in a blue moon when my control system fecks up.
tom
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daviep
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| posted on 4/4/10 at 08:02 AM |
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I don't understand the question I think a drawing would probably make it a bit clearer.
Regards
Davie
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smuty
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| posted on 4/4/10 at 09:14 AM |
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quote:
Originally posted by indykid
i know there are a few pro welders on here so my question is if someone said i want a 10mm throat butt weld on a lump added onto a 32mm bar, would you
laugh at them, or would you just get on with it?
detail behind the question's in the next post
cheers
tom
think its a 10mm fillet weld your after
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indykid
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| posted on 4/4/10 at 10:36 AM |
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this is what i mean.
the top of the square face would be impacted if the sled ever hit it.
i could increase the length of the bar to give a fillet weld top and bottom but there's no room for it on the sides
thiking about it, i'll probably spec it as that just to save messing with trying to bevel the round face.
any other thoughts though, keep them coming.
cheers
tom
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MkII
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| posted on 4/4/10 at 11:38 AM |
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from what I can see on your drawings if it was prepared and welded properly the 2 pieces would never come apart.....ever. .m.
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blakep82
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| posted on 4/4/10 at 11:41 AM |
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looks plenty strong to me.
if this was for a one off thing, but high use, then the cost of getting something cast in one solid piece could probably be justified?
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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skinned knuckles
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| posted on 4/4/10 at 11:51 AM |
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quote:
Originally posted by blakep82
looks plenty strong to me.
if this was for a one off thing, but high use, then the cost of getting something cast in one solid piece could probably be justified?
X2
A man isn't complete until he's married, then he's finished
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indykid
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| posted on 4/4/10 at 12:24 PM |
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cast and impact sounds bad to me.
bringing a 29kg plate travelling at 7m/s to rest in 6 milliseconds requires an average force of 40600N......4.1 tonnes in static terms
i think it looks strong enough too. the maths agrees but it's the technicalities of producing the weld i need to know about.
it's a 2 off btw so casting/forging are not an option
ta
tom
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jacko
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| posted on 4/4/10 at 12:27 PM |
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Yep looks good to me thats how i would do it
Jacko
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indykid
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| posted on 4/4/10 at 12:48 PM |
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quote:
Originally posted by jacko
Yep looks good to me thats how i would do it
Jacko
just the man!
cheers graham
tom
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blakep82
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| posted on 4/4/10 at 01:04 PM |
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ah yeah, not casting then, but who about machining on a CNC mill or something?
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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indykid
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| posted on 4/4/10 at 01:10 PM |
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quote:
Originally posted by blakep82
ah yeah, not casting then, but who about machining on a CNC mill or something?
that's more feasible.
could turn it down from bigger bar then mill the sides off, but the EN8 i have at uni is bright rolled.
not got any cylindrical grinding facilities at uni and i need a smooth finish for the plain bearings it rotates in. if it were turned, i could spec
needle roller bearings but that introduces more complexities than it solves
tom
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Mark Allanson
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| posted on 4/4/10 at 01:11 PM |
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Just weld with low hydrogen rods, the weld will be stronger than the parent material. E6011's from memory, but make sure they are ultra dry when
you use them (use a heated quiver)
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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stevebubs
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| posted on 4/4/10 at 02:52 PM |
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Whatabout a thick dowel through the pair of parts?
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gazza285
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| posted on 4/4/10 at 08:42 PM |
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quote:
Originally posted by Mark Allanson
Just weld with low hydrogen rods, the weld will be stronger than the parent material. E6011's from memory, but make sure they are ultra dry when
you use them (use a heated quiver)
E7018. You need a DC set for low-Hys as well. If you are going to that much trouble, then why not go for full pen? Wouldn't take much more
effort, as long as the guy welding it is coded for full pen.
DO NOT PUT ON KNOB OR BOLLOCKS!
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iank
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| posted on 4/4/10 at 08:50 PM |
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quote:
Originally posted by blakep82
ah yeah, not casting then, but who about machining on a CNC mill or something?
My understanding is a machined forging would be better than either cast or CNC milled from billet. (due to the crystalline alignment)
But a welded part would seem to be up to the job if done by a professional welder.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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