Mig Welding 3/8 steel

[Dozerash]

I have a project at work to weld 3/8” thick plates together. They are 18”x48”, I have to weld them together on the 48” side. The plate will be used to cover a hole in the driveway/storm drain. I will be using a Miller 211 Mig welder with .030” solid wire with gas (because that’s all we have). Any suggestions? I figure I will be running the welder pretty much maxed and will weld both sides. Should I stitch weld or run solid bead? I’ve never Mig weld something this big or long of bead before. At home or other jobs I have had we would just use a stick welder. Thanks

 

[CA_Bgrwldr]

If it were me, I would bevel both sides of the plates, tack weld one side, flip it and weld up the seam using 4-6" stitch welds, flip it back over and weld up the first side.

 

[jhn9840]

I agree with CA_Bgrwldr. If I had a choice stick would be an easier option.

jhn9840
John

 

[Gary Fowler]

If it were me, I would bevel both sides of the plates, tack weld one side, flip it and weld up the seam using 4-6" stitch welds, flip it back over and weld up the first side.

If the plate needs to be absolutely flat when finished, CA Bgrwldr has a good way to reduce the warping due to weld contraction. You would need to alternate welding one pass on each side to equalize the stress.

Personally, I would not want to manhandle that big plate with each pass and if you are like me, you could try the following. MY choice would be to weld it from one side similar to the following. When I would test a structural welder on 1/2" plate, I would have him tack it up by putting a 1/8" 6010 rod under each plate at the weld bevel so the plates had a backward V slant of about 10 degrees. After welding up the single V bevel the plates would be flat due to the compression of the weld metal when cooling. I think that would work for your plates also and you could just weld them up from one side.

 

[Gary Fowler]

I have a project at work to weld 3/8” thick plates together. They are 18”x48”, I have to weld them together on the 48” side. The plate will be used to cover a hole in the driveway/storm drain. I will be using a Miller 211 Mig welder with .030” solid wire with gas (because that’s all we have). Any suggestions? I figure I will be running the welder pretty much maxed and will weld both sides. Should I stitch weld or run solid bead? I’ve never Mig weld something this big or long of bead before. At home or other jobs I have had we would just use a stick welder. Thanks

Well after all the "advice", how did you weld them and what was the results?