Tig welding SS problems

admin

How come my welds are black instead of the dime stack look and shiny?Syncrowave 250HF startElectrode neg.20-25 amps Attached Images
Reply:Material is 18g 304
Reply:Gray welds on stainless usually means you got the material too hot or that you moved the shielding gas away too soon or didn't have enough coverage. 18ga is around .047 or so IIRC. that means you should be up around 40-50 amps roughly. Running at 25 amps you are going to slow.  It seems counter intuitive, but more amps usually means you put less heat total into the work. By welding at a much lower amp setting, you have to really linger and wait for things to heat up. That means that a larger area heats, and it takes longer to dissipate that heat. As soon as your weld leaves the shielding gas and it's still hot, it discolors. Going with more amps allows you to keep your puddle small, yet move faster reducing the total energy that needs to dissipate before you loose the shielding gas..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWGray welds on stainless usually means you got the material too hot or that you moved the shielding gas away too soon or didn't have enough coverage. 18ga is around .047 or so IIRC. that means you should be up around 40-50 amps roughly. Running at 25 amps you are going to slow.  It seems counter intuitive, but more amps usually means you put less heat total into the work. By welding at a much lower amp setting, you have to really linger and wait for things to heat up. That means that a larger area heats, and it takes longer to dissipate that heat. As soon as your weld leaves the shielding gas and it's still hot, it discolors. Going with more amps allows you to keep your puddle small, yet move faster reducing the total energy that needs to dissipate before you loose the shielding gas.
Reply:You are too hot, the large heat zone on both sides of the weld is an indication.  Look on the inside at the pentration and you will also see the problem.  Argon shield, 3/32 308L SS and about 25 cfh on the flowmeter.
Reply:Thanks for the input. I was using 316 filler. Could that be an issue as well?
Reply:Looks to me like a gas issue. What size cup are you using? Standard collet body or gas lens? Shielding gas flow? Also, what does the backside look like? To save yourself the trouble of rigging a backpurge, find yourself a nice thick piece of aluminum angle to clamp into the corner. It acts like a chill bar and a purge dam at the same time. Use the biggest cup you can find, and about 20~25 cfh gas flow.Also, try slowly tapering off your amperage @ the end of the weld, that'll get rid of the shrinkage pore in your stops. Good luck!
Reply:Originally Posted by PFD402Thanks for the input. I was using 316 filler. Could that be an issue as well?
Reply:looks like an issue with gas coverage to me, but there's certainly heat input issues to address. I would recommend clamping a piece of aluminum, maybe 1/4" thick, to the inside of the corner while you weld. it will help soak up the heat a lot, but you need to consider you machine settings also. More amps means you need a faster travel speed. heat input is a function of travel speed. amps/volts affect the heat input, but not nearly as much as travel speed. in other words, a couple more amps and moving faster will reduce you heat input greatly.
Reply:i personally prefer 1/16" 2% thoriated tungsten and a .035" filler on something that thin.
Reply:sorry for all the replies, i keep having afterthoughts.....but you might also want to tighten up your arc length. keep that tungsten JUST above the puddle, as close as you can without touching it.