Miller Electric

Welding Discussion Forums

Home » Resources » Communities » Welding Discussion Forums
 
Miller Welding Discussion Forums - Powered by vBulletin

Page 1 of 3 123 LastLast
Results 1 to 10 of 25

Thread: Aircraft Alloys

  1. #1
    Join Date
    Feb 2008
    Location
    flat , and lots of dirt
    Posts
    123

    Default Aircraft Alloys

    THEY say that 7075 is not weldable........

    I agree
    THEY say that 2024 is not weldable........

    I disagree

    I assembled two pieces of 2024-t3 .063 at 90 degrees and using 4043 rod had a flawless weld, strong enough that I bent that 90 till the edges were touching, and not a crack in sight.

    No such luck with the 7075, just puddling on a flat piece resulted in a fatal crack from edge to edge after cooling.


    Why do THEY say that 2024 is not weldable?
    Is this old mis-information from the 70's when we did not have the tecnology that we have today?

    I was so pleased with the results from the 2024 that I would be willing to fly on those welds. What gives?
    SYNCROWAVE 200
    Atlas 618 lathe (vintage 1960) reconditioned DC
    Sioux 3/8 Pneumatic Reversible Drill
    Makita Everything else
    2400 square feet of Sanford and Son lookin shop space
    "Once the spoon flys, putting the pin back in won't solve anything"
    USA 15T, 15V

    www.myspace.com/blackbird455

    http://i100.photobucket.com/albums/m...5/DSC00356.jpg two cans, one welder

  2. #2
    Join Date
    Feb 2008
    Location
    flat , and lots of dirt
    Posts
    123

    Default

    This is quoted from ESAB's site, you know, the company that stands on the soapbox quoting themselves every chance they get "we invented welding"
    I knew a guy that worked for Dow or Dupont, I forget, in Millington, Tn., that developed the original vacuum chamber heliarc process. Anyway,

    Be Aware:

    It should be stressed that the problem of higher susceptibility to hot cracking from increasing the coherence range is not only confined to the welding of these more susceptible base alloys such as 2024 and 7075. Crack sensitivity can be substantially increased when welding incompatible dissimilar base alloys (which are normally easily welded to themselves) and/or through the selection of an incompatible filler alloy. For example, by joining a perfectly weldable 2xxx series base alloy to a perfectly weldable 5xxx series base alloy, or by using a 5xxx series filler alloy to weld a 2xxx series base alloy, or a 2xxx series filler alloy on a 5xxx series base alloy, we can create the same scenario. If we mix high Cu and high Mg, we can extend the coherence range and, therefore, increase the crack sensitivity.

    I see this , but like I said, I tested my weld, way past what I would ever expect from it, and IT DID NOT CRACK!!!!!!!

    I will dye check it tomorrow , but it held up better than my 6061 .063 tests.
    SYNCROWAVE 200
    Atlas 618 lathe (vintage 1960) reconditioned DC
    Sioux 3/8 Pneumatic Reversible Drill
    Makita Everything else
    2400 square feet of Sanford and Son lookin shop space
    "Once the spoon flys, putting the pin back in won't solve anything"
    USA 15T, 15V

    www.myspace.com/blackbird455

    http://i100.photobucket.com/albums/m...5/DSC00356.jpg two cans, one welder

  3. #3
    Join Date
    Mar 2007
    Location
    Oahu, Hawaii
    Posts
    2,469

    Default

    I just got dizzy READING that!
    I'm not late...
    I'm just on Hawaiian Time

  4. #4
    Join Date
    Dec 2005
    Location
    wisconsin
    Posts
    836

    Default

    Whoever said its not weldable probably oversimplified things a bit as the old books list it as being very weldable but useless in the as-welded condition. Sure you can weld it, but the base metal looses all its strength. The 2xxx series metals are heat treatable ( hence T3, T4 etc ), and most of the time they are used in some form of heat treated state. Welding ( except resistance ) usually leaves part of the HAZ in the "0" condition or close to it. In the old days, 2024 was torch welded, and re-heat treated all the time, so nothing special or new here. Same with Tig is done commonly today. Just welding it though leaves you with a very expensive piece of soft aluminum.
    So sorry to say, your "new" technology is no better then anything else in this matter .

    -Aaron
    "Better Metalworking Through Research"

    Miller Dynasty 300DX
    Miller Dynasty 200DX
    Miller Spectrum 375 extreme
    Miller Millermatic Passport

    Miller Spot Welder
    Motor-Guard stud welder

    Smith, Meco, Oxweld , Cronatron, Harris, Victor, National, Prest-o-weld, Prest-o-lite, Marquette, Century Aircraft, Craftsman, Goss, Uniweld, Purox, Linde, Eutectic, and Dillon welding torches from 1909 to Present. (58 total)

  5. #5
    Join Date
    Nov 2006
    Location
    Lake of the Ozarks MO
    Posts
    3,588

    Default

    And also one way to look at it is why would you WANT to weld it?? How did you know that was the alloy BTW?
    If you re-heat treated it back to it's original state and you used the wrong filler it might fail testing horribly
    On your 6061 test it was not really meant to be bent as tempered but once again welding lost your heat treat and softened it.
    I've been bending pipe on some projects I'm working on and as tempered 6061 T-6 pipe breaks quite impressively when stretched I must say. 6063 is much nicer
    Aluminum is a different animal for sure...sometimes it takes years to figure out what works and what don't. Re-reading stuff regularly helps because after a while just one word or phrase can enlighten a situation greatly.

    www.facebook.com/outbackaluminumwelding
    Miller Dynasty 700...OH YEA BABY!!
    MM 350P...PULSE SPRAYIN' MONSTER
    Miller Dynasty 280 with AC independent expansion card
    Miller Dynasty 200 DX "Blue Lightning"

    Miller Bobcat 225 NT (what I began my present Biz with!)
    Miller 30-A Spoolgun
    Miller WC-115-A
    Miller Spectrum 300
    Miller 225 Thunderbolt (my first machine bought new 1980)
    Miller Digital Elite Titanium 9400

  6. #6
    Join Date
    Aug 2007
    Location
    Northern California
    Posts
    193

    Default Lincoln Article, FWIW.

    Here's an excerpt from a Lincoln article on common mistakes in aluminum welding. The link to the entire article is shown below.

    I don't know about 2XXX series alloys but I heard about the problems that the Honda Motor Company had with the 1800 Goldwing motorcycle that came out in 2001. It was the first large touring machine that they had built with an aluminum alloy frame. I understand that they used 7XXX alloys and that they were robotically MIG welded on the assembly line. To make a long story short, they had lots and lots of cracks. They finally did a recall and ultimately replaced some of the frames. Others were re-welded by the factory and also outside certified shops that worked to their specifications and used Honda's repair instructions. The repairs were done with TIG after grinding out the welds. Apparently they changed their procedures by sometime in 2003 or 2004 and then had no further troubles. To their credit, they handled the matter quite well and no one was injured although I understand that some of the bikes fell apart on the road. Live and learn.

    Here's the excerpt about 2XXX, among other things.
    -----------------------------------------------------------------------
    Common Mistakes Made in the Design of Aluminum Weldments
    By Frank G. Armao, Senior Application Engineer, The Lincoln Electric Company, Cleveland, Ohio

    <snip>
    The heat-treatable alloys are contained in the 2XXX, 6XXX, and 7XXX alloy families. The 2XXX family of alloys are high strength Al-Cu alloys used mainly for aerospace applications. In some environments, they can exhibit poor corrosion resistance. In general, most alloys in this series are considered non-weldable. A prime example of a non-weldable alloy in this series, which is attractive to designers because of its high strength, is alloy 2024. This alloy is commonly used in airframes, where it is almost always riveted. It is extremely crack-sensitive and almost impossible to weld successfully using standard techniques.

    Only two common structural alloys in the 2XXX series are weldable: 2219 and 2519. Alloy 2219 is very easily weldable and has been extensively welded in fabricating the external tanks for the U.S. space shuttle. This alloy gets its good weldability because of its higher copper content, approximately 6%. A closely related alloy, which is also very weldable, is 2519. It was developed for fabrication of armored vehicles. Although there are detailed exceptions to this rule, the designer should probably consider all other alloys in the 2XXX series to be non-weldable<snip>

    http://www.lincolnelectric.com/knowl...comistakes.asp

    Synchroman
    Last edited by Synchroman; 03-15-2008 at 02:40 PM.

  7. #7
    Join Date
    Feb 2008
    Location
    flat , and lots of dirt
    Posts
    123

    Default

    Quote Originally Posted by FusionKing View Post
    And also one way to look at it is why would you WANT to weld it?? How did you know that was the alloy BTW?
    Uhh....cause of the red letters and numbers on the 48 x 144 sheet that say over and over "alclad 2024-t3" as all aircraft alloy sheet does, cause you dont want to use 6061 where you need 7075, and you dont want 7075 where you need 2024, bad failures have resulted from this all too often. Don't know if you have ever worked with 7075, but the stuff *rings* like stainless. It is brutally strong, but get one crack in it and it is Tango Uniform!!
    I saw a beam made of 7075-T6 , transmission support beam on an MH-60A Blackhawk that the ACE team just happened to find. It had a small corrosion crack on the bottom, and it appears that after the corossion crack formed, it split from one side to the other, stopped only by the horizontal part of the "I" beam.

    I also own some 7075-O , and 2024-O, and tomorrow I will go take a pic just to clarify..... but the point that the pieces of 2024-t3, as welded, bent outside of the HAZ . and it took a good bit of torque to bend it, not even close to "O" condition, that merely bends when you lay it down on an uneven surface.
    SYNCROWAVE 200
    Atlas 618 lathe (vintage 1960) reconditioned DC
    Sioux 3/8 Pneumatic Reversible Drill
    Makita Everything else
    2400 square feet of Sanford and Son lookin shop space
    "Once the spoon flys, putting the pin back in won't solve anything"
    USA 15T, 15V

    www.myspace.com/blackbird455

    http://i100.photobucket.com/albums/m...5/DSC00356.jpg two cans, one welder

  8. #8
    Join Date
    Dec 2005
    Location
    wisconsin
    Posts
    836

    Default

    Quote Originally Posted by Blackbird455 View Post
    Uhh....cause of the red letters and numbers on the 48 x 144 sheet that say over and over "alclad 2024-t3" as all aircraft alloy sheet does, cause you dont want to use 6061 where you need 7075, and you dont want 7075 where you need 2024, bad failures have resulted from this all too often. Don't know if you have ever worked with 7075, but the stuff *rings* like stainless. It is brutally strong, but get one crack in it and it is Tango Uniform!!
    I saw a beam made of 7075-T6 , transmission support beam on an MH-60A Blackhawk that the ACE team just happened to find. It had a small corrosion crack on the bottom, and it appears that after the corossion crack formed, it split from one side to the other, stopped only by the horizontal part of the "I" beam.

    I also own some 7075-O , and 2024-O, and tomorrow I will go take a pic just to clarify..... but the point that the pieces of 2024-t3, as welded, bent outside of the HAZ . and it took a good bit of torque to bend it, not even close to "O" condition, that merely bends when you lay it down on an uneven surface.
    How do you know the extent of the HAZ? It could be further then you think. From an engineering perspective, Leaving the part in the "as-welded" condition is useless, unless its spot or seam welding. 2024 is nothing new, its been worked, welded, formed, riveted and tested for over 65 years. If you want to find some interesting reading material, look for military aircraft welding handbooks from the 1950's. They typically cover OA, ARC, TIG, MIG, Laser, Spot, and ultrasonic welding, Steels, aluminums, magnesiums, alloy steels, cast materials etc, and interesting to see what processes they found to work the best on cetain materials etc. No offence to any of the welding equipment companies, but to me it seems like the modern welding books are more of an advertisement anymore, while maybe not directly. Even the newer AWS manuals, ever notice who sits on the board that writes them?

    -Aaron
    "Better Metalworking Through Research"

    Miller Dynasty 300DX
    Miller Dynasty 200DX
    Miller Spectrum 375 extreme
    Miller Millermatic Passport

    Miller Spot Welder
    Motor-Guard stud welder

    Smith, Meco, Oxweld , Cronatron, Harris, Victor, National, Prest-o-weld, Prest-o-lite, Marquette, Century Aircraft, Craftsman, Goss, Uniweld, Purox, Linde, Eutectic, and Dillon welding torches from 1909 to Present. (58 total)

  9. #9

    Default

    There's really very few metals that aren't weldable, and very few that can't be welded together (whether its practical or not is a whole nuther issue) successfully, i know of ABSA registered welding procedures for copper to mild steel piping (B31.3 piping systems).

    They may say some things can't be welded, but whats the reasoning behind it, and i garantee that there's probably some way around it, but then again is it practical.

    Precipitation hardened aluminum alloys are tricky to weld and be able to leave in an as welded stated because the heat from welding overages the material, thus making it very hard and very prone to cracking.

  10. #10
    Join Date
    Nov 2006
    Location
    Lake of the Ozarks MO
    Posts
    3,588

    Default

    BlackBird455...I guess my point is sort of like this...If you wanna weld that stuff on your own plane and fly over your own field all by yourself go ahead and be my guest.
    Otherwise take all your welding books and all other technical manuals along with any advise from people who work with the stuff for a living and toss them in the trash
    Or you could start your own independent testing lab and PROVE the world wrong!
    Some things you just need to have a little faith in the people who came along in this profession before you. Just because something looks good and bends ONCE don't mean jack compared to the millions of cycles something see's in a critical application. Remember each vibration is a cycle so maybe trillions is more like it. You just gotta believe their is a reason why you don't weld it and then put into service. It might be just fine for a thing around the shop or whatever, just not for human movement.

    www.facebook.com/outbackaluminumwelding
    Miller Dynasty 700...OH YEA BABY!!
    MM 350P...PULSE SPRAYIN' MONSTER
    Miller Dynasty 280 with AC independent expansion card
    Miller Dynasty 200 DX "Blue Lightning"

    Miller Bobcat 225 NT (what I began my present Biz with!)
    Miller 30-A Spoolgun
    Miller WC-115-A
    Miller Spectrum 300
    Miller 225 Thunderbolt (my first machine bought new 1980)
    Miller Digital Elite Titanium 9400

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Warning: Function split() is deprecated in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/footer.inc.php on line 82

Welding Projects

Special Offers: See the latest Miller deals and promotions.