Hello my name is Matt. Lets see if I can help.
Osha requires that all receptacles at 20 amps and below be protected by a GFI So probably you have a small welder that is a 110 model that has a standard male cord end connector that you can plug into any receptacle correct?
The way to solve this issue is to either hard wire the cord into the power source (This way something else with a standard male plug end cannot be plugged into it) or change the male cord end on the welder to a twist lock type 120 volt 20 amp and then change the receptacle to the matching female twist lock type. The code is in place to protect against standard 110/120 volt items from being plugged in without GFI protection. If you change the type of plug to a non standard type then it will only work with specilized equipment. If you want to be able to plug your welder into a standard outlet somewere else then you can make a short adaptor cord just for your welder to go from twist lock to standard.
Does this help?
I'm on site & unable to evaluate your answer. But I will by the end of the week.