- Thread starter s410man
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This is the video i was on about around a minute in you can see the gates springing back straight
Basically what is the best /most efficient way of doing this-it says in the video hear treated but after some more specific info
Can't get the video link to work sorry it's titled Rappa mobile yards on YouTube
Cheers
Basically what is the best /most efficient way of doing this-it says in the video hear treated but after some more specific info
Can't get the video link to work sorry it's titled Rappa mobile yards on YouTube
Cheers
Screwdriver
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Wow. That's an impressive amount of springyness for aluminium. Must be a carefully selected alloy AND with some very clever heat treatment.
Difficult to make anything to match that. If you were going to try, I suggest you buy a sample and have a good look at it. It might even have some clues for the particular grade of alloy etc. My guess is the heat treatment would be a closely guarded secret. I wouldn't tell you!
S.
Difficult to make anything to match that. If you were going to try, I suggest you buy a sample and have a good look at it. It might even have some clues for the particular grade of alloy etc. My guess is the heat treatment would be a closely guarded secret. I wouldn't tell you!
S.
norlander
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Bl---y hell, thatsa bit special innit
I wonder if that is the "Rolls Royce" set up, and maybe that spec is not absolutley necessary?.
Maybe have a word with Mr Justme above, he probably knows what kit is used, or knows folks who do. Think the Royal Welsh Show has been and gone for this year, pity, might have been good for fact finding.
Anyway, quite a challenge, hope you get there, good luck, let us know how it turns out.
Bl---y hell, thatsa bit special innit
I wonder if that is the "Rolls Royce" set up, and maybe that spec is not absolutley necessary?.
Maybe have a word with Mr Justme above, he probably knows what kit is used, or knows folks who do. Think the Royal Welsh Show has been and gone for this year, pity, might have been good for fact finding.
Anyway, quite a challenge, hope you get there, good luck, let us know how it turns out.
I did have a bit of a ask about at the royal welsh but they're just reps there didn't seem to know much about the heat treatment bar what is says in the brochure
There's a few companies making them so can't be a very good secret I'm just wondering exactly what is done to them!!
Don't really need them to be that bendy but obviously can't crack as soon as sheep push them-unbelievable the amount of pressure a group of sheep can force upon a fence!!
Thanks for all the advice so far
Cheers
There's nothing particularly special about that springyness... while it's UTS is similar/a nats lower the yield strength of 6082-T6 is a bit higher than plain 'ol low carbon steel ERW tube. Yield strength of 7020-T6 is a bit higher again and the UTS is a bit higher than some cheap ERW steel tube IIRC. Those Rappa yards look to be in the ballpark of 30 - 32mm OD for the main hoops, probably 3mm wall(?)... a similar length of 6082-T6 tube would respond about the same to the boot test and while the walking over it demo looks more impressive the forces are spread over a much longer span plus there's some play in each of the panel joints
There's not really any secrets when it comes to the flavours of ally that mere mortals can buy... boffins have played about with the stuff for eons to see what happens when it's aged naturally and at various different temps & times to work out what gives the best compromise of mechanical properties for different flavours and how they can be tweaked this way or that. For example while overaging typically results in a sharpish drop of strength the tradeoff can be improved corrosion properties with some alloys; https://www.lightmetalage.com/PDFs/LMA-2010-08-016-T-Temper.pdf
No matter what's done with heat treatment welds ain't gonna respond exactly the same because matching filler wires don't really exist... there is no 6xxx series filler wire due to problems with solidification cracking, usual choices are 4043 or 5356 which aren't heat treatable so weld response will depend on dilution. 4643 is a wire designed to fix that but it's effectively unobtanium and is designed more around multipass welds. With something like 7020 several different 5xxx series can be used, 5180 is the closest to a 7xxx series (i.e. AlZnMg) but again pretty much unobtanium for mortals. Basically tweaking heat treatments ain't gonna transform things
A more indepth look at the effect of heat treatment and welding on 7020 http://cdn.intechweb.org/pdfs/13396.pdf but it's not the lightest of reads
My money is still on a 6xxx series, probably 6082, or 7020. Annealing won't be part of the final heat treatment. They're gonna be buying material in large enough quantities to probably buy the tube in a softer state like T4 instead of the usual T6 temper. Like i said stuff in the T6 temper can need locally annealing to bend successfully which is obviously a PITA if everything you make involves bending the stuff. Annealing (partially at least) is gonna be a side effect of welding along with overaging if you start with material in the T6 condition
If they're starting off with say 6082-T4 then they may just artifically age it after fabrication or, more likely, 'fully' heat treat it i.e. solution treatment followed by artifical aging. Something like 7020 would just be artificially aged
Temps and times vary a little with source but in the ball park of 510 - 540°C solution temp for 6082, quench in water kept below 70°C, straighten if/as necessary and age at 165 - 190°C for 3 - 12 hours. Aging times & temps for 7020 are discussed in the second link
There's not really any secrets when it comes to the flavours of ally that mere mortals can buy... boffins have played about with the stuff for eons to see what happens when it's aged naturally and at various different temps & times to work out what gives the best compromise of mechanical properties for different flavours and how they can be tweaked this way or that. For example while overaging typically results in a sharpish drop of strength the tradeoff can be improved corrosion properties with some alloys; https://www.lightmetalage.com/PDFs/LMA-2010-08-016-T-Temper.pdf
No matter what's done with heat treatment welds ain't gonna respond exactly the same because matching filler wires don't really exist... there is no 6xxx series filler wire due to problems with solidification cracking, usual choices are 4043 or 5356 which aren't heat treatable so weld response will depend on dilution. 4643 is a wire designed to fix that but it's effectively unobtanium and is designed more around multipass welds. With something like 7020 several different 5xxx series can be used, 5180 is the closest to a 7xxx series (i.e. AlZnMg) but again pretty much unobtanium for mortals. Basically tweaking heat treatments ain't gonna transform things
A more indepth look at the effect of heat treatment and welding on 7020 http://cdn.intechweb.org/pdfs/13396.pdf but it's not the lightest of reads
My money is still on a 6xxx series, probably 6082, or 7020. Annealing won't be part of the final heat treatment. They're gonna be buying material in large enough quantities to probably buy the tube in a softer state like T4 instead of the usual T6 temper. Like i said stuff in the T6 temper can need locally annealing to bend successfully which is obviously a PITA if everything you make involves bending the stuff. Annealing (partially at least) is gonna be a side effect of welding along with overaging if you start with material in the T6 condition
If they're starting off with say 6082-T4 then they may just artifically age it after fabrication or, more likely, 'fully' heat treat it i.e. solution treatment followed by artifical aging. Something like 7020 would just be artificially aged
Temps and times vary a little with source but in the ball park of 510 - 540°C solution temp for 6082, quench in water kept below 70°C, straighten if/as necessary and age at 165 - 190°C for 3 - 12 hours. Aging times & temps for 7020 are discussed in the second link
