Welding A390.0 aluminum castings

By Lawrence (*****)

Date 06-17-2002 17:25

http://www.castingsource.com/tech_art_guide1.asp

Check this out. While it gives little useful instruction in specific welding technique it does provide what appears to be an excellent performance table. If you were to share some more specific information about your casting such as, size, geometry, and intended service conditions we might be able to give some general hints as to fixturing, pre/postheat etc.

Good Luck

Lawrence

By jasiv Date 06-17-2002 20:25

Lawrence,
Thanks for the link. Unfortunately, that was the exact same site that I was refering to in my initial post. The application is rather unique: build-up of the dome on aluminum pistons. As far as fixturing is concerned, that shouldn't be a problem. However, based on the alloy content and the conditions that the piston is subjected to, pre/post weld heating info would be helpful. What I'm finding to be the most challenging is finding the proper filler metal for this alloy. Thanks for your help.
John

By pdweldor (*)

Date 06-18-2002 21:48

Try contacting Alcotec, a producer of aluminum welding wires. www.alcotec.com.

Their literature says to use 4043, however, this alloy is somewhat "leaner" than the 359.0 casting(5% Si vs. 9%), and thus will be lower strength. Also, 359.0 is heat treatable for strength due to the addition of a small amount of Magnesium in addition to the large amount of silicon, indcated by the T6 temper designation. You might want to look into 4643, which is similar to 4043 and welds similar, but it has a little Mg in it to make it also somewhat heat treatable.

One thing to keep in mind, the heat affected zone of the weld will be weaker than the base metal, so you need to think about how that will impact you. You would have to heat treat after welding to get the properties back. Heat treating adds its own set of problems, and wouldn't likely be possible on a precision machined piston.

Regards.

By jasiv Date 06-19-2002 13:14

Thanks for the info. I will check out Alcotec, but what you gave me answered the majority of my questions. Thanks again.

JOHN

By Brett B (*)

Date 06-19-2002 17:26

We are welding cast Al. 360 roughly 1/8" thick and are using
4008 or 4145 alloys from Alcotec with very good results
using the GTAW process.

We recently switched to a Lincoln Powermig 300
with Pulse on Pulse and it is giving us a tig welded quality
with the speed of GMAW using 3/64 4043 - Alloy.
It seems as though the pulse on pulse was getting rid of
porosity issues we were having when we tried to pulse or traditional C.V. mig weld them.
As a side note we are pushing through a standard mig gun
with a teflon liner with good results.

Brett B.