As you mention, European 2-wire 240V single-phase consists of a grounded neutral and a 240V hot, but US 2-wire 240V consists of two 120V hots. Because the voltage is correct, the machine will almost certainly function on a US 240V supply. You don't need the neutral from the outlet / panel, just the two 120V hots wired to the machine hot and
Many of the tiny, cheap, generic stick welders look almost the same and all seem to have similar claimed specs. Some are 120V, some are 240V and some are du
bLvl18G.