hi, I am having problems mig welding a small heat exchanger (mild steel), the welds look ok, but when I pressure tested the unit I found several pin holes. The steel has been cleaned with a flap wheel prior to welding, the joints were all very good, ie No big gaps to fill, but I cant seem to stop these pin holes appearing. my worry is that there are more weak spots that will develop a leak after installation, when its going to be difficult to get at to repair or even to see a leak properly. any Ideas what the problem might be.
I have cleaned and rewelded the holes, pressure tested to 5 bar, now it seems ok, but I have more to do at a later date and I would like to try illiminate the faults before I do the next one.
Any suggestions would be appreciated.
Just for info, I have been welding for 40 years, plant, trucks, cars, tractors with Arc, Mig and gas, The welder I am using for this work is a Migtronic, with 0.8mm wire, I have used this welding up to 1" plate, so I know there are no power issues, also I am using argon/co mix ( dont know the ratio)
Plate thickness is 3mm to 8mm, pipe joints welded are 1/2" bsp (they welded ok, no leaks)
cheers
bob
I have cleaned and rewelded the holes, pressure tested to 5 bar, now it seems ok, but I have more to do at a later date and I would like to try illiminate the faults before I do the next one.
Any suggestions would be appreciated.
Just for info, I have been welding for 40 years, plant, trucks, cars, tractors with Arc, Mig and gas, The welder I am using for this work is a Migtronic, with 0.8mm wire, I have used this welding up to 1" plate, so I know there are no power issues, also I am using argon/co mix ( dont know the ratio)
Plate thickness is 3mm to 8mm, pipe joints welded are 1/2" bsp (they welded ok, no leaks)
cheers
bob