Alright, I'm going on about 5 weeks (i'm guessing), of crash course TIG welding. My class at my vocational school was overstaffed with 19 people and 1 teacher, so the supervisor brought in another teacher. One of his main jobs was to make sure I earned the certifications I was looking for during his time there, so he went at it with the straight-forward intent to get me those certifications. The first was a 3/16'ths t-joint in 6061 aluminum with a 1/8th 4043 filler rod. The second, a stainless steel 3/16th's 5-joint with 304 stainless and a 1/16th 308 rod.
My tests were completed and turned in Monday and I should get the results on Wednesday. I feel very comfortable with stainless. My beads look awesome, like raindrops lying on top of one another. I'm very proud of what I've got there.
My aluminum on the other hand disappoints me. I'm pretty sure I passed the certification as I could see penetration almost completely through the plate (you could see the distortion on the back of the plate). However, I don't feel I can accomplish this on a regular basis and I don't like the visual appearance of my bead. I can't quite get that "layered dime" look. I had a teacher in my beginning class who could weld aluminum with TIG and make it look like icing on a cake. My beads look more like someone took that nice string of dimes and smudged them out from side to side. I tried smaller rods with the same results.
Also, on penetration, I can only be sure of achieving penetration, by burning ahead of my puddle and then coming back to it. I think this contributes to my large smeared bead, but whenever I don't do this, I don't have good results and my piece doesn't usually pass the break test (we put it in a vice and wack it with a hammer :) )
Could you guys give me some advice? I tried preheating with the tungsten torch before actually running a bead and my actual test plates were preheated with the acetylene torch. I didn't think preheating was as important unless you were up to a 1/2" or something.
The plates on my test weren't bevelled either.
What do you guys think? I have 3 more classes before I start my pipe welding class and go back to stainless. The teacher is now finished as he was only brought on to help with my certifications, so I don't have the benefit of the extra teacher anymore and I have an open curriculum for the next 3 classes. I'm gonna practice practice practice.
Mathius
Mathius,
http://www.lincolnelectric.com/knowledge/articles/content/tigalum.asp
See if there is something here that you might be overlooking(ie. preheat, cleaning, etc...).
Hope this helps,
John Wright
Here are a couple more links that have excellent information on process control for GTAW aluminum
http://www.millerwelds.com/pdf/Aluminations_Ad_Package.pdf
http://www.millerwelds.com/education/tech_articles/articles30.php
After reading them bring on the questions.
a good tip for getting your tip tounded is turn the settings to DCRP and let the tip get rounded. it might fall off but its ok, and then turn it back for alum. but it makes the tip shiny and round. and i always use a foot pedal cuz i had the same problem with alum. looking like that. its when the metal just gets to hot and puddles to crap. but try the pedal and then let off of it when it is puddled. but i hope i helped you
magicmarker is right about the heat, if it is too hot your weld bead will become wider, also if you use bigger piece of alum you will get more heat sink. Also, make sure you got all the oxide off the surface of the aluminum because that can cause porosity, it also makes it harder to get penetration.It doesn't take very long for aluminum to oxidize. What size wire are you using and what class wire are you using? ex. 4043 3/32? I can give you some advice as to what gas coverage and amps to use
Topic American Welding Society Services / AWS Learning & Education / I need more aluminum help (TIG)
