[themadreefer]

having problems with machining tig welded aluminum, using lincoln tig 225 machine. 3/32 2% lanthanated tungsten, 4043 filler rod.
welding on 2" diamater 3034 aluminum parent metal.

using my typical tooling in my lathe, as i always use and get a smooth finish. but with the welded aluminum, metal looks like it is being ripped or torn.

only thing i have not tried was chaning speed on my lathe

any ideas would be helpful

thanks
archie

[nova_70_383]

the only thing i can think of here is tungsten inclusions. if you machine over them they tend to rip.

[themadreefer]

i hear you. but that sure would be a lot of inclusions. my gut feeling is to much heat while welding, or wrong filler rod.
will post picture later
thanks

[bbaedke]

I have noticed the same problem. The 4043 is soft and tends to tear and leave little bits on the cut surface. You could try increasing speed (800 to 1000 rpm) to avoid a built up edge, or try a coolant/lubricant.
This forum has a suggestion that waiting a few days before machining may make the weld harder and less gummy: http://www.practicalmachinist.com/vb/ge ... num-82026/

Other things to try:
--A coated carbide insert (TIN coating is slippery)
--Very sharp high speed tool bit ground with lots of rake
Here is a cutting speed calculator: http://littlemachineshop.com/Reference/ ... Speeds.php

[mike boyer]

Hey T..Stretch here...Been a manual machinist for 30yrs..Aluminum is a bitch in and of itself..Not to mention stuf thats been welded..Best advice & wats workd for me is this..Stay away from insert type carbides..if thats wat your using.. carbide theory is heat and pressure..you literly tear off the metal..hense the blue chips on REAL METAL..works great on steel and tuff stuff...But you need a KNIFE EDGE for the softer stuff..ie: aluminum & most composit plastics..Get you a piece of GOOD 1/2" tool bit stock and hand grind a big dish or "scoop" right behind the leading edge(mine are half way thru the tool bit)..And a lot of face clearance in front of it...crank up the rpms and feed speed,hose it down with WD40 or kero and let er rip....(don't be shy with it as ur cuttin either)Make sure uv'e got a chip puller bouta foot or so long..You'll geta continous chip(or birds nest as we call um "THAT WILL ABSOLUTLY RUIN YOUR DAY IF YOU GIVE IT THE CHANCE"),but it will finish smooth as glass an if your speeds n feeds are right..u'll geta mirror finish..Clean with accetone to get all the nastys out before handin to sparky or you'll geta good cussin for sure...lol..Hope this helps you out..Let me know how it turns out for you..Thats just one version of the down n dirtys..