When using the welding machine, stack the cleaned straight steel bars together and place them between the two electrodes, step on the pedals to make the intersection of the two steel bars tightly contact, and the circuit breaker is also in contact with each other, and the power supply is switched on to make the steel bars take over The spot generates a large amount of resistance heat in a short time, and the steel bar is quickly heated to the melting point and is in a molten state. When the pedal is released, the circuit breaker cuts off the current as the lever descends. Under the action of pressure, the melting point of the steel bar cools and condenses into a welding point.