can 7050 and 6061 be welded together?

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Does anyone know if 7050-T7451 and 6061-T6 can be welded together?  If so, would 5356 be the appropriate rod to use?
Reply:The 7xxx aluminum alloys are usually NOT weldable, with only limited exceptions.The 7xx alloys with more than 0.2% copper are considered unweldable.  7050 is 2-2.6 % Cu.Nope, not weldable.  The best laid schemes ... Gang oft agley ...
Reply:thanks MoonRise
Reply:Why?Does it have to be those metals!Can you use 7039 instead.What are you doing that the properties need tio be these?Carring a load strength or what.There are ways to weld them together using a third wire in the 5000 series, but you have materies that are super strong why weld thwn and lower the strength at the welded zone.
Reply:For the weldability of aluminum alloys:http://www.steelforge.com/alloys/?alloy=7050Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:If you look up the properties for 7050 it is considered unweldable by normal methods, ie MIG and TIG.6061 is considered weldable as long as filler metal is added.Maybe the 6061/7050 combination may be weldable with additional filler, try 4043 or 5356.  Sounds like a real long shot though.  Even if it welds you will have a weld of unknown properties, I would stay away from the 7050 if it were me."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Originally Posted by noriteIf you look up the properties for 7050 it is considered unweldable by normal methods, ie MIG and TIG.6061 is considered weldable as long as filler metal is added.Maybe the 6061/7050 combination may be weldable with additional filler, try 4043 or 5356.  Sounds like a real long shot though.  Even if it welds you will have a weld of unknown properties, I would stay away from the 7050 if it were me.
Reply:My 2c - when an aluminum alloy referred to as "unweldable", its just another way of saying that it is "highly sensitive to hot cracking."  Hot cracking means that the welded puddle or solid weld bead when cooling, cracks inside the weld bead.Here is one example of what hot cracking can look like.  Notice there is no "necking down" of the material around the crack.  The crack occurred before the material cooled sufficiently to really develop anywhere near the strength it may have at room temperatureAlloying ingredients generally have certain % ranges where the material is highly sensitive to hot cracking.  So sometimes selecting a filler rod with different alloying ingredients (or same ones in different proportions) can make a difference with affecting crack sensitivity of the cooling weld bead.  Along the same vein, diluting the weld bead with an additional % of filler rod can help.  (For example, setting up a butt weld up with a wider than normal gap to be filled.)I've welded crack sensitive dissimilar aluminum alloys together before by varying the joint prep (IE: wider gap spacing of a butt weld) to allow additional % dilution of the weld bead with filler rod.  Pre-heating plays a small role as well because the cracking is caused by cooling of the weld bead.  You can also experiment with different filler rods.  Braizing (with zinc-aluminum braizing rod) might even be an option.  I would experiment on test coupons of same alloys and thicknesses as your work requires, using different variables mentioned above until you achieve results satisfactory for your application.Last edited by jakeru; 01-25-2011 at 03:31 PM.