Advanced DC Welding Machine / Medium Frequency Welding Studs Into Steel Plate DESCRIPTION This machine are mainly use to welding studs/bolts into iron or steel plate . It adopts medium frequency dc welding power source. MF DC Inverter Spot Welder is a set of advanced welding equipment. The welding transformer is in small size but the outout energy is large. Three-phase AC will be converted into DC after being rectified. Then the DC will be converted into medium frequency