Metalurgy question

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I have a set of aluminum(not sure of grade) triple trees off my Harley at powder coat. He is currently baking them at 500° for an hour to outgass them. I have never dealt with aluminum and heat stress. Is this something I should be concerned or not worry about it? I'm not sure but this may be the 2nd bake at 500 for an hour. They have also been cooked at 300-350 twice to cure the powder. Sent from my XT1058 using Tapatalk
Reply:Aluminum is hardened using "precipitation hardening" in which it is heated up, quenched, then reheated and held at that temperature for hours. Usually between 3 to 30 hours. 500 degrees is not even close to what it would need to be initially heated to and an hour is definitely not long enough to change anything.There's a crazy science behind heat treating, quenching, and annealing, but a pretty good rule of thumb is that in order to make any substantial changes to the metal, it needs to be initially heated close to its melting temperature which is about 1,200 degrees for aluminum. And just to clarify, this is all in Fahrenheit. I took a class in college on this kind of stuff (how to get a metal to have certain mechanical charicteristics using heat treating, quenching, annealing, etc) but that was a little while ago so someone correct me if I'm wJohn 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:It really depends on the grade of aluminum.  Here's a nice brief summary of heat treating 6061 aluminum alloyhttp://www.thefabricator.com/article...ation-for-6061If your part is 6061 alloy, then you may have softened the material.  It depends on what temper it was to begin with.  If it's some other alloy, then maybe nothing will have happened.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:They are cast I just thought of that. I'm going to clean a spot off and do a brinell on them to see what they look like hardness wise. If they are to soft guess someone is buying me a new triple tree. Sent from my XT1058 using Tapatalk
Reply:I'm a long time Harley owner and also do powder coat. I've done lots of triple trees at 375 deg. F. and never had any problem with out gassing damaging the finish when completed. I'd have to think twice about 500 deg. F., though. It may not weaken or anneal the metal but I'm no metallurgist, either. LOL Generally most aluminum melts at around 985 deg. F. 500 isn't that close, but I doubt that it's necessary with Harley products. I'm thinking that the same out gassing process could be done at a lower temperature for a longer time. I know that heat treating of chrome plating for removal of excess hydrogen to prevent embrittlement in the aircraft industry, say for landing gear struts is generally done at 300-350 deg. F. for overnight.Miller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set
Reply:Depends on the grade of alum. Alum gas cylinders are automatically junk at 300 deg F as temps at or above that change the structural properties of the alum alloy. Powder coating cylinders is an automatic fail on inspection..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWDepends on the grade of alum. Alum gas cylinders are automatically junk at 300 deg F as temps at or above that change the structural properties of the alum alloy. Powder coating cylinders is an automatic fail on inspection.
Reply:Not really sure what I'm going to do yet. I may do some brinell and go from there it just worries me a little knowing how hard I ride and how rough the roads are here. Sent from my XT1058 using TapatalkLast edited by Letzgoracin301; 04-02-2014 at 06:19 AM.
Reply:Why would they owe you a new triple tree?I guess I'm reading this wrong, seems the problem is you decided to do some customizing and have parts powder coated.You knew heat was involved. If the parts are no longer as good as they were in stock form, you are at least equally at fault.I know the business should also know what the effects are from their own process - I just think it's a wash.Maybe I'm wrong, have been before...Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:I knew heat was involved but not that much. Cure is around 350. Not 500. If I had known he was going to bake them at 500 for an hour I would have said NO. Its one thing on car parts or less critical parts but a tree takes abuse of every bump. Sent from my XT1058 using Tapatalk
Reply:Originally Posted by EcondronAluminum is hardened using "precipitation hardening" in which it is heated up, quenched, then reheated and held at that temperature for hours. Usually between 3 to 30 hours. 500 degrees is not even close to what it would need to be initially heated to and an hour is definitely not long enough to change anything.There's a crazy science behind heat treating, quenching, and annealing, but a pretty good rule of thumb is that in order to make any substantial changes to the metal, it needs to be initially heated close to its melting temperature which is about 1,200 degrees for aluminum. And just to clarify, this is all in Fahrenheit. I took a class in college on this kind of stuff (how to get a metal to have certain mechanical charicteristics using heat treating, quenching, annealing, etc) but that was a little while ago so someone correct me if I'm w
Reply:I'm just gonna run them and keep an eye on it for a while. If I rode like most Harley riders I wouldn't have given a second thought. But since we leave every other stop light with the wheel in the air it raised a little concern. Sent from my XT1058 using Tapatalk
Reply:Oh, you wheelie? LOL. I'm tool old for that. That causes other problems so don't worry about the triple trees. Miller Millermatic 252Miller Syncrowave 200Liincoln AC-DC 225Victor O-A Set
Reply:No wheelies that's just crazy but when you leave hard it tends to carry the wheel. Plus with the new motor work I'll be over 100 horse on a wide glide. Sent from my XT1058 using Tapatalk
Reply:Got my stuff back. Probably going to eat it and send the sliders and lower tree to another powder coater. Thank god its my personal ride because the job is poop. Sent from my XT1058 using Tapatalk