My Clarke (made in Italy) worked fine here. Then again it was made for the US market. Only difference from the europe version is it is 120V.
Many Europe welders are 230 volt and the only thing you would need to change is the plug. You would probably have to do that anyway on a US/220V unit as they usually don't come with a plug.
As long as you can match the voltage setting, it should work. 3 phase is an issue as there are so many different voltages (208,220,380,430 in US, 415 in UK.) 50/60 HZ will effect duty cycle, they will be more efficient on 60Hz.
European voltage regulations are standardised at 230V plus or minus 10% which works out at 207V to 253V. The supply frequencies don't tend to make a lot of difference.
I run a Miller Syncrowave on the 208V setting on a supply of about 245V and it seems fine. I think transformer based welders don't mind so much so long as you are close. Invertor welders might be a bit more fussy.