Welding aluminum - type of alloy?

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I have a swingarm off a CBR 600rr.  I am going to have it profesionally welded, as I have no clue how to tig and dont really want to "learn" on such an important part.  I am not sure what type of aluminum this is made of, I am going to try to find out.  I need to cut a part of this off and then weld in a filler plate.  Do I have to use the same type of alloy, or can I make the plate out of any aluminum?  I am going to be buying the little piece and fabbing up the plate, and then paying someone to weld it.  I dont really want to pay them to make something I can make myself, thats why I am going to make the plate and not just have them do the whole thing.  Thanks.Last edited by cbrf23; 12-06-2005 at 12:40 PM.
Reply:Chances are it's 6061-T6.   That alloy is fairly easy to find and, yes, you should use the same alloy for the part to be welded on to the swingarm.There are no small projects
Reply:I agree with imagineer that the swing arm is 6061-T6 , that is the most commonly used aluminum in welding, unless of course the item is subject to marine use than you would use a 5000 series aluminum such as 5051. But I am quite sure the swing arm is 6061, I would use a 4043 tig rod to weld it
Reply:4043 is a good choice of filler metal for 6061 if the welded assembly will be heat treated for strength (-T6) after welding.  The weld will contain a mixture of 4043 and 6061 that will respond to heat treatment.4043 may also be used without postweld heat treatment, but the weld strength will be that of 4043.For higher strength without postweld heat treatment, 5356 may be used (possibly others, not sure).  The strength properties of the joint will transition from 5356 in the weld, to annealed (soft) 6061 in the heat affected zone, to 6061-T6 base metal.
Reply:I don't have any experience heat treating aluminum, but I did recall from past reading that it used much lower temperatures and was inverse from steel (annealed at higher temperatures).  I found the following:Precipitation hardening is done at 320 F for 18 hours and air cool, followed by 350 F for 8 hours and air cooling.It suggested that this process would produce the T6 temper.  There might be other considerations that I'm not aware of, like deformation, but it would seem that this process could be done in a standard oven if the part is small enough to fit and the thermostat on the oven is reasonably accurate.  I wonder if anyone else on the forum has experience heat treating aluminum?-Heath
Reply:Well the guys over at 600rr.net said that they thought it was this: 6061 T-651 or T-6  So I guess you guys were right!  lol. thats crazy how much you all must know about metal and welding!  I am not going to be performing the welding, I just needed to know what kind of metal to use to make my plate.  I only need a piece like 7 inches by 6 inches probably, does anyone know how much that will cost?  I'll search around but just curious.  Or maybe, for such a small piece, could I pick up some scrap from a shop?  Thanks for all the quick replies, very helpful people on this forum!
Reply:Try Metal Supermarkets.  They aren't really cheap, but they'll do for small quantities.  You might also try McMaster-Carr.  Again, they're not cheap, but they do small quanitities.http://www.metalsupermarkets.com/http://www.mcmaster.com-Heath
Reply:Originally Posted by cbrf23Well the guys over at 600rr.net said that they thought it was this: 6061 T-651 or T-6  So I guess you guys were right!  lol. thats crazy how much you all must know about metal and welding!  I am not going to be performing the welding, I just needed to know what kind of metal to use to make my plate.  I only need a piece like 7 inches by 6 inches probably, does anyone know how much that will cost?  I'll search around but just curious.  Or maybe, for such a small piece, could I pick up some scrap from a shop?  Thanks for all the quick replies, very helpful people on this forum!
Reply:{4043 is a good choice of filler metal for 6061 if the welded assembly will be heat treated for strength (-T6) after welding. The weld will contain a mixture of 4043 and 6061 that will respond to heat treatment.}I was doing some research on the same subject at the lincoln site and they say neither 4043 or 5356 alloy is heat treatable. anyone know why they would say this?steveBTS Welding
Reply:I was doing some research on the same subject at the lincoln site and they say neither 4043 or 5356 alloy is heat treatable. anyone know why they would say this?steve[/QUOTE]  Because only 2xxx,6xxx,and 7xxx aluminum alloys are strenghened by parcipitation hardening. 1xxx,3xxx,4xxx and 5xxx are only hardenable by work hardening and solid solution hardening. (adding alloying elements)
Reply:Originally Posted by steve butera{4043 is a good choice of filler metal for 6061 if the welded assembly will be heat treated for strength (-T6) after welding. The weld will contain a mixture of 4043 and 6061 that will respond to heat treatment.}I was doing some research on the same subject at the lincoln site and they say neither 4043 or 5356 alloy is heat treatable. anyone know why they would say this?steve
Reply:This is directly out of Welding Filler Metal Data Book by Esab for 6061 for maximun strength, maximum ductility, and best color match after anodizing 5356 is the best choice, for maximum salt water corrosion resistance and least cracking tendancy 4043 is the best choice.
Reply:Bottom line IMO is, when you cut the swingarm and weld a piece of alum. to it, the welded/heated area wont have the same strength as it once had.what you are cutting and welding on the swingarm is critical. without seeing what you are actually doing, its hard for me to truely make a call on what to do.as far as the heat treatment after its welded is concerned,  i dont know if you can re- heat the whole unit and get uniform results.do you know a company that can heat treat it correctly? I do know that after some time, the weld zone hardens on its own.  again, i dont know if this would be enough strength.If you tried to contact honda for some info on the material used, they would frown on what you are attempting to do.  thats not to say what you want to do cant be done though.get another swingarm for back up and give it your best shot.
Reply:Originally Posted by cbrf23I have a swingarm off a CBR 600rr.  I am going to have it profesionally welded, as I have no clue how to tig and dont really want to "learn" on such an important part.  I am not sure what type of aluminum this is made of, I am going to try to find out.  I need to cut a part of this off and then weld in a filler plate.  Do I have to use the same type of alloy, or can I make the plate out of any aluminum?  I am going to be buying the little piece and fabbing up the plate, and then paying someone to weld it.  I dont really want to pay them to make something I can make myself, thats why I am going to make the plate and not just have them do the whole thing.  Thanks.