stainless MIG problem

admin

hello, i am an emergency welder. i run heavy equipment and when something breaks, i do an emergency weld. i have a very nice lincoln MIG 255 and i am running 035 316 stainless with 100% argon.problem is the arc is jumping all over the place, especially when things heat up a bit.seems like it works ok, a bit splattery, but ok for a minute or so. then the arc starts flaring out and then just jumps right to the tip and welds the wire to it.everything is clean, i use splatter spray, i have replace the tip twice.............right now i am building a housing for a hydro-electric plant out of 1/4" 316 stainless.
Reply:Do you usually use 100% argon for stainless MIG?  I though stainless MIG was better run wiht tri-mix gas?Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by nadreggidhello, i am an emergency welder. i run heavy equipment and when something breaks, i do an emergency weld. i have a very nice lincoln MIG 255 and i am running 035 316 stainless with 100% argon.problem is the arc is jumping all over the place, especially when things heat up a bit.seems like it works ok, a bit splattery, but ok for a minute or so. then the arc starts flaring out and then just jumps right to the tip and welds the wire to it.everything is clean, i use splatter spray, i have replace the tip twice.............right now i am building a housing for a hydro-electric plant out of 1/4" 316 stainless.
Reply:You can spray stainless. I prefer a 98/2 mix. It wont work out of position though. Get some trimix and set your machine to 20v 300ipm as a starting point. I weld on millers with 308 wire most of the time so your settings will be slightly diff. For spray i would be at 24v 400+ipm with 98/2
Reply:Had a similar problem to that a while ago on mils steel.After checking gas, internal connections, changing tips,  etc...I found that the splatter spray was melting and getting in the contact tip and caused problems.Now i only spray the gas shield inside while it is off the gun.I spray the contact tip on a downward angle as to not get none in the hole.It may help.......it might or might not be your problem.
Reply:use a tri mix on ss
Reply:thanks guys, some good ideas, i will try.although i did say i am an emergency welder, not a good welder............i can usually keep the machine working.sometimes it is tricky, like a broken cylinder shaft...............but, so far so good.anyway, i have no experiance with spraying. i looked it up and i think that is what is happening. what position is best?also, i have heard that too much heat will cause impurities in and around the weld that may cause rusting. but i was just trying anything to see what might work, and when i cranked the speed up to like 400 and the amps all the way up, it was spraying and it made a nice looking weld......but i thought i might be screwing it up so i stopped.how do i check the gas? it might be tri-mix............
Reply:Spray arc MIG welding is best done in the flat or horizontal positions.  Some wires/machines/settings can run out-of-position, but this is the exception, not the rule for spray arc.  If you need to run out of position, you need to use short circuit transfer settings or a machine with pulsed MIG capability.Welding stainless and holding the materian between 800 - 1500°C can lead to a loss of corrosion resistance.  Some portion of the material will spend some amount of time in this temperature zone as the weld cools.  The keys to avoiding problems are to minimize the time in this temperature range and to use filler metals with the 'L' designator(308L or 316L for example); 'L' is for low carbon content.Chances are you stumbled into a workable set of parameters for the machine if the weld looks OK and you were using spray arc transfer.  Spray arc is very hot and gives a weld bead with good penetration.  You can have bad penetration from short circuit transfer and the bead will still look OK if you don't know what you're doing.  At 400 inches per minute, and voltage maxed, chances are that you were in spray arc mode.The gas mixture should be labeled on the cylinder somewhere.  It's required by OSHA.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Short Arc w/ Tri Mix Gas (Blueshield 9)