Polarity is nothing but the direction of electrical current flow from the electric circuit.
AC and DC welding?
AC- Alternative current which flows in one direction for half of the time and then takes reverse direction, but we look into DC- Direct current which flows in only one direction.
Learn Polarity?
The welding machine has two poles Negative and Positive with the help of these two poles skilled welders suggest the right polarity which results in strong and quality weld.
An unskilled welder or a beginner may take the wrong decision to choose the wrong polarity which leads to a lack of penetration, excess spatter, and loss of welding arc control – yes all these are common troubleshooting when we choose the wrong polarity.
Types of Polarity?
Three types of welding polarity were there;
- Direct Current Straight Polarity.
- Direct Current Reverse Polarity.
- Alternate Current Polarity
Direct Current Straight Polarity VS Direct current Reverse Polarity?
Direct Current Straight Polarity
Straight polarity is said when the flow of electrons travels from the electrode tip to welded plate when the plate is connected to the positive terminal and the electrode is connected to the negative terminal.
Here the arc strikes the plate and two third of the heat is generated in the electrode and only one-third in the plate. So the downside of the plate did not fuse properly due to the low heat arc produced in the plate. It results in a lack of penetration and excess weld.
Direct current Reverse Polarity
Direct Current Reverse Polarity differs from straight polarity. The plates were connected to the positive terminal in reverse polarity and electrodes in the negative terminal. Here flow of electrons from the plate to an electrode results in the high generation of heat and deep penetration is achieved.
Slag Inclusion flaws are less due to the fast welding process in Direct Current Reverse polarity. In Reverse polarity, electrode life is shorter and a high level of reinforcement is observed if the welder fails to set the correct speed. It works better in thin materials when compared to thicker materials.
