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Tig 2" 304 sch 40 to 1/4 plate
Posted: Wed Nov 20, 2019 11:45 pm
by rjs261989
Having trouble with oxidation any tips? Using 2% lanth 309 filler. Scratch start at 120 amps
Re: Tig 2" 304 sch 40 to 1/4 plate
Posted: Thu Nov 21, 2019 2:32 am
by weldin mike 27
It may not mean much, but 309 isn't the correct filler for that job. It's specifically designed for welding mild steel to stainless steel.
Re: Tig 2" 304 sch 40 to 1/4 plate
Posted: Fri Nov 22, 2019 12:12 am
by Poland308
Depending on the material your plate is 309 is dissimilar carbon steel to stainless steel. 308 would be a good choice if it’s 304 to 304. Or also acceptable on 304 to 316.
Oxidation is caused by the metal being too hot or exposed to air while it’s too hot. Poor gas coverage is a possibility but in my mind least likely. I’d guess it’s from getting too hot, either your running too low of amps and the part is getting heat soaked or your just plain running too many amps.
If your not grinding a bevel on the pipe but just welding it directly to the plate open end of the pipe to the face of the plate, and the plate is over 12 inches x 12 inches then I’d recommend trying around 90 to 100 amps and use 3/32 filler wire. Don’t try to weld a fillet over a 1/4 inch wide. If you require a wider or thicker weld do it in several passes. Or bump up to around 105 and use 1/8 filler. If your surface area of your plate is less than 12x12 then go down in amps maybe as low as 70 but stay with 3/32 filler and narrow passes.