we will have straight polarity and reverse polarity,we can produce the weld with good quality
Some electrodes (welding rods) can be used AC or DC. Some are strictly DC. You may find that most electrodes run smoother on DC. Most industries purchase machines with DC capability.
Dc welding can be used for non consumable electrodes with consumable electrode heat is transferred from electrode to work by molten metal. Ac welding is desirable for aluminum and magnesium, because it helps break up oxides AC is more stable than Dc.
Yes, it is normal for a welding machine to convert AC voltage to a DC voltage.
Often because with DC, it is possible to change the direction of the weld current for the task at hand.
rectifyer
In a welding machine, the rectifier is responsible for converting AC into DC. AC current fluctuates, but DC provides a steady flow, making welding smoother and easier to control. Many welders prefer DC for its stable arc and reduced spatter, which leads to cleaner welds. Some machines even offer both AC and DC options, allowing welders to choose based on the material and type of welding they need to perform.
DC WELDING:We gain a smoother welding because of constant and linear direction of current.The arc will be more stable and easier to handle.DC welder can use both AC and DC welding rods.AC WELDING:The arc is not stable here and needs to be stuck again because of the fluctuating nature of AC.It is not as smooch as DC welding.These welders cost less when compared to DC welders.
DC-
I am not sure your question is clear enough but here I go... Stick Arc Welding (AC or DC), MIG (Metal Inert Gas) and TIG (Tunsten Inter Gas). All three of these are the basic metal welding machines.
The difference in the ac/ dc , or polarity of welding rods is in the makeup of the flux coating , or the alloy of the metal, and in the case of SMAW ( Shielded metal arc welding ) rods , which have a flux coating, are usually marked on the base of the rod.
Can be either, or even selectable.
Both currents have their ups and downs but both are used in the maufacturing industry, in reality it depends on your base metal and electrode.