inter pass guidelines for 6061

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I've been doing some automotive parts for a local shop that have a lot of welding to be done in a relatively small part. So I'm looking for some guidelines for inter pass temps for 6061. Is it even an issue with aluminum?
Reply:Problem with alum is it transfers heat so fast and you are welding all over the part. You can try to limit how hot the part gets, but my best advise is to quench in room temp water to try to get it up to a T-2 condition immediately upon completion of welding. At T-2 you will initiate some natural aging to approx T-4 over time. Over T-4, it will take some artificial aging.Don't know about you, but I prefer to use 5356 as a high strength as-welded filler alloy. I find that it somewhat strains the HAZ to prod it up to T-2 when quenching. That and quenching is about all you can do.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:i would never cool by water , but that is me...  hot alum will tend to crack but who am i to say ---i'm a dumb welder (welding aluminum for 20yrs)weld a little then let cool, weld a little then let cool, --maybe cool in front of a fanidealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:Originally Posted by prop-doctori would never cool by water , but that is me...  hot alum will tend to crack but who am i to say ---i'm a dumb welder (welding aluminum for 20yrs)weld a little then let cool, weld a little then let cool, --maybe cool in front of a fan
Reply:Originally Posted by prop-doctori would never cool by water , but that is me...  hot alum will tend to crack but who am i to say ---i'm a dumb welder (welding aluminum for 20yrs)weld a little then let cool, weld a little then let cool, --maybe cool in front of a fan
Reply:Our procedures specify 350 deg. interpass on aluminum.
Reply:It is a good idea to cool them slow as well. -Try to use a fast welding speed, I mean higher amperage so you can make your weldment faster.-You also want to avoid mixing to much of the parent metal with your weld deposite.--To much penetration = more chances of hot shortness.
Reply:Originally Posted by welds4dOur procedures specify 350 deg. interpass on aluminum.
Reply:Ignore it. But seriously, most of what I do in aluminum is single pass, so interpass doesn't come into play.
Reply:Annealing of 6061 occurrs somewhere between 600 and 700 degrees. Anywhere  below 500 degrees interpass is ok. The hotter the part after welding the more stength lost, and most beneficial for retaining/regaining strength by water quenching.Better be careful of slow cooling. It does take some time for 6061 to detemper. If you are sitting on the puddle and you overheat your part, and you let is slow cool, you will not regain T2 hardness, and will not allow the part to naturaly age back to T4.Suit yourself regarding quenching. At least put a fan on it.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Why put a fan on it shovelon?
Reply:Originally Posted by DanthemanWhy put a fan on it shovelon?
Reply:use 4043 alm wire as your filler. most compatableWELCOME HOME TO ALL VIET-NAM VETERANS
Reply:Originally Posted by shovelonAnnealing of 6061 occurrs somewhere between 600 and 700 degrees. Anywhere  below 500 degrees interpass is ok. The hotter the part after welding the more stength lost, and most beneficial for retaining/regaining strength by water quenching.Better be careful of slow cooling. It does take some time for 6061 to detemper. If you are sitting on the puddle and you overheat your part, and you let is slow cool, you will not regain T2 hardness, and will not allow the part to naturaly age back to T4.Suit yourself regarding quenching. At least put a fan on it.
Reply:Aluminum melts at 650 dregree Celcius.Any quenching of any metal and non-ferous ( aluminum included ) is no good if you dont want it to be crack prone.I dont know why after everything that you have been told you still insist on quenching your part.You will have the best result by not deluting the parts been welded more then 10% in with your filler material.Keep it warm while you weld and COOL IT SLOW.
Reply:Originally Posted by quasiInteresting thoughts. Most of the work I've done has been on the DC setting of my machine so I'm not exactly a pro at this fancy aluminum stuff. Although I have been certified under D 17.1 for aluminum before.  On top of that I've always viewed any sort of heat treating as something for a specialized tradesmen. Sounds like I should read up on tempering aluminum. If quenching is needed to reach T2 is water the same as oil? The parts I'm making have been done by people in the past that I'm pretty sure haven't given so much as a casual thought to any of this. The part in question (intake manifolds) have never had a weld failure. So I suppose that makes this topic more of an academic curiosity than problem curing. That said I'm interested in manufacturing said parts as best I can without sending them off to be heat treated.
Reply:Originally Posted by shovelon5356 filler will induce a bit of straining on the areas adjacent to the weld, encourage a rise in hardeneing, hopefully to T2. Remember once it cools and is at T0, it is at T0 forever until you heat it, bring it into solution, and lock it in with water quench.
Reply:Originally Posted by 4sfedDon't forget that 5356 is susceptible to stress corrosion cracking at service temperatures above 150°F.  If this is an intake manifold, at least the flange bolted to the head will run hotter than that . . . if it's an intake for a turbo, much of it will regularly exceed 150°.  Otherwise I agree that quenching the part after welding will result in a stronger part.