Aluminum welding penetration

[Kiev Fernandes]

a test piece of 10mm thickness 60 degree v 1mm root face and 2mm root gap.

while passing the root run, penetration cant be seen on the other side, the weld material is less than an mm stuck in the vee. is this a problem for welder qualification. can i jus back grind and pass an other run. is root penetration nessary for the qualification of the welder. we have been having a lot of problems. increasing the current and voltage results in the melting of the tip.

Kiev feds

[tazmann]

Hello Kiev
For that joint config the lincoln guide says 2 passes front and 1 on the back for a flat position weld with temp backing. what diameter wire you using?
Tom

[Kiev Fernandes]

hey tom

the prob is only with the root pass the weld material does not seem to pass through to the other side of the root gap. the thickness of the plate is 10mm with a root gap of 2 to 3mm no luck. wire used is 1.2 and 1.6.

kiev

[tazmann]

Kiev
Couple things come to mind to check. Should be running in no pulse mode, 1.6 wire, push angle on the gun not drag, tip to work a little to close, wire speed a little slow longarcing, Temp backing bar have groove cut in depth and width from the welding guide?
In that root its going to be hot and fast 250 amp range , moving to fast or slow will cause lack of penatration also.
Tom

[Kiev Fernandes]

hey y should it be in no pulse mode????? all our machine r on pulse. the tip tends to melt if th current exceeds 180 amps.

[tazmann]

Kiev
Most my aluminum welding is on lighter material but from my understanding pulse is good up to about 1/4" material. If when your running in cv mode and your melting the tips at 180 amps somthings wrong, Whats your guns amp rating and are you running water cooled ?
DC electrode + ? correct tip size for aluminum ?
Myself I run in cv mode above 3/16" 5mm.
Pulse cycles through high and low amps, keeps the amps high enough on the high side to stay in spray mode, that way you can weld on material less than 3mm and stay in spray mode. If you are running in pulse and cranked up to 180 amps, the high side af the amp cycle is way above that, might be why your melting tips. hope I explained that right?
What does it do in non pulse CV mode ?
Tom

[Accurate twrs]

Use all the protocall and preparation you have been taught... grind your test plates with the v on both sides and use tabs on the start and the finnish..

Little trick on the root pass... your going to get a bottle of helium and a y valve to run 10% mix helium and your normal argon. Use this mix for all your passes. It will run hot so be carefull. The helium will bring all dirt and porosity to the surface to grind before the next pass...The helium works like a dream. Do not tell anyone bout the mixture... got it !!!!

Start on the tab and run the root to the other tab.. backgrind til you clean the root then weld again... finnish the one side.

Turn it over and backgring again weld the backside grinding between each pass till finnished... When finnished and happy with your work then bandsaw the tabs off. Submit your test plate..