Okay, the most common Casting alloy used in transmission housing (US alloy, that is... Germans usually use their own alloys) is 201-T6. Now this is a basically comercially pure aluminum with 4.5% Cu (copper) added. With 7% elongation, it will have a tensile strength of 70,000psi and a yield strength of 63,000psi. That similar to 7075-T6 to give you an idea as to the strength. ANYWAYS, to get that kind of strength, the alloy uses what is called Solidification strengthening. The casting molds and processes are designed very carefully to have the best compromise of grain structure. It is then probably artificially heat treated. When you weld the material, you are re-melting and cooling the material around the heat affected zones which not only remove the solidification strengthened properties, you are probably warping the areas around it as the stored energy is released... basically you can find a broken transmission with a good case and use that without the worries you will have if you try to weld an already broken transmission case. And if they are using a truly non-weldable alloy... it'll be even worse. In order to do a proper job if you decide to weld over the hole I suggest you send a small piece to a metal testing company and ask them to find the alloy out (about $15 ea) and then get the right welding rod and someone familiar with welding that alloy. Later, Clayton
[email protected] wrote: > On Tue, 18 Jan 2000 09:12:29 -0800 Clayton <[email protected]> writes: > > Most castable aluminum alloys aren't weldable... if you want a more > technical explaination on the list I can provide but I didn't > > want to bore the list. > > Clayton > You wouldn't be boring us. 8^) > > Let's hear it. > > Peter > '79 Scirocco 16V project car > '80 Scirocco > '88 Scirocco 16V > '83 GTI, daily driver > '87 GTI 16V for parts > > > > ________________________________________________________________ > YOU'RE PAYING TOO MUCH FOR THE INTERNET! > Juno now offers FREE Internet Access! > Try it today - there's no risk! For your FREE software, visit: > http://dl.www.juno.com/get/tagj. _____________ List Sponsor: http://www.netsville.com To remove yourself from this list, send mail to [email protected] with 'unsubscribe a2_16v' in the body of your message See us on the web at http://www.a2-16v.com Visit the 16V Homepage at http://www.gti16v.org
