Reply With QuoteAluminum is going to loose most of the strength at that temperature. Aluminum will age or overage more rapidly at elevated temperatures further reducing strength. Why not steel?
Hello All,
Long time lurker, first time poster!
I have recently been carrying out some fire tests and a question has resulted from those tests on a particular component. I have a spray bar made, in the first instance, from a 1050 aluminium pipe 8mm dia, 1mm wall section as a prototype because we have it in stock and it's easy to hand form. This has survived 6 tests where it was exposed to a maximum of 500oC rising from ambient in approximately 4 minutes.
The production items were going to be 6060 T66 but, on discharging the extinguishers this alloy shattered into quite a number of pieces. there are clear fractures in the metal and where it was less exposed it is bubbling/rupturing on the surface
There isn't a great pressure in the spray bar, estimated low single figures (<3BAR).
Can this be simply explained? I'm happy to continue to production with the 1050 or change to steel but would like to know what has caused this to happen.
Thanks for any assistance offered.
Bob
Aluminum is going to loose most of the strength at that temperature. Aluminum will age or overage more rapidly at elevated temperatures further reducing strength. Why not steel?
"Because race car!" I need to save as much weight as I can and this is an easy win in the overall system. The 1050 was surviving and has done during at least 6 trials, what's got me is why the 6060 T66 alloy which has a higher strength, 1050 is almost pure aluminium after all, has failed where the 1050 hasn't?Originally Posted by Hudson
I should note that this is an extreme condition. Normal temperature will be no higher than 120oC ambient and the period of exposure to the upper temperature would be very short when something catastrophic has already happened, maybe <30secs. It's then replaced anyway.
Last edited by Bobos; 07-19-2015 at 05:55 AM.
Hi Bobos,
Here's my guess on your situation...
You mention the 1050 being easy to hand form. I'm guessing you cracked the 60 series material before you even applied any pressure to the part / nozzle or whatever it is. The alloyed up aluminums need to be annealed before working them then heat treated back to the T6 or T66? You can move them in the hard state a wee little but if you move the material a good bit it's going to crack. Moves like butter annealed... shatter like glass hard.
One problem is unless you're buying a mill run of the material you won't be able to find anyone selling it in the annealed condition. So you buy what you can... send it to your local house that treats aluminum... form it... send it back to bring it back up to T6... and Voila!! Now you'll have a much stronger part than your 1050 part.
Bob
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