What is a positive connection?
When DC arc welding, the weldment is connected to the positive terminal of the output terminal of the welding machine, welding torch (welding pliers)
The connection method of the negative terminal of the output terminal is called "positive connection method" and is also called positive polarity.
2. What is the reverse connection method?
When DC arc welding, the weldment is connected to the negative terminal of the output terminal of the welding machine, welding torch (welding pliers) The connection method of the positive terminal of the output terminal is called "reverse connection method" and it is also called reverse polarity. Basic electrode (junction 507, etc.), carbon arc gouging, CO2 welding are reversed.
3. Why does the DC TIG welding secondary output circuit connect to the DC positive connection? Which gold is suitable for Is the welding of materials?
When DC is connected, tungsten is extremely negative, cathode area emits electrons, temperature is low, and tungsten is very low.Not easy to burn, you can use a larger welding current. Suitable for welding carbon steel, stainless steel, copper, titanium and refractory metal molybdenum, tantalum, niobium, etc.
4. Why do we need to use AC TIG welding to weld aluminum, magnesium and its alloys?
When DC is reversed, tungsten is extremely positive and generates more cations with higher kinetic energy.The oxide film striking the surface of aluminum, magnesium and its alloys has a cleaning effect; tungsten is extremely positive In the polar region, the temperature is very high, and the tungsten is extremely damaged and cannot be used with a large welding current.Normal welding. Using an alternating square wave power supply, heating the workpiece in the positive half wave, negative half wave cleaningThe oxide film realizes high quality welding of aluminum, magnesium and its alloys.
5. What is the initial current (initial current)?
A: In the “arrest” state of the arc, press the current of the welding torch to start the arc; loosen the torch to open.
Turn off the welding current.
<1>When TIG welding, the starting current is less than the welding current for preheating and guiding the arc
The welding wire is directed to the welding area, and the torch switch is released to switch to normal welding.
<2>MIG welding aluminum, the starting current is greater than the welding current 20-30A, reducing the starting point of welding Not fused.
<3> MIG welding of stainless steel and steel, the starting current is equal to the welding current.