This document discusses arc welding and the differences between DC and AC welding machines. DC welding machines have a fixed polarity which allows them to weld both thick and thin materials. AC welding machines do not have a fixed polarity and cannot be used for all types of welding. The document also explains the concepts of straight polarity, reverse polarity, and how the magnetic field created during welding enables both forward and reverse welding depending on the direction of electrode movement.

1. ARC Welding Machine By- Anandpatel Submitted to- Ajankyaphatak {HOD}

2. Today I am discussing about Arc welding. We know Arc welding is two type Then when I was studied welding .then infront of me some question.such as Why?DC welding are used for all types of welding{thick or thin material} Why AC welding machine are not .

3. AC welding{why does not weld alltype of joint} Ac welding polarity are not fixed… Due to polarity changes we cant use for all type of welding

4. DC welding machine{we use weld for thick materail} Fixed polarity With the help of fixed polarity.we can handle accoring to use thick or thin welding.

5. What is concept behind polarity If work piece is connect with positive terminal and electrode are connected with negative terminal then this type of polarity..called “straight polarity”

6. REVERSE POLARITY If work piece are connected with negative terminal and electrode are connected with positive terminal then this type of welding we called “Reverse welding”

7. How can work polarity When we flow current in electrode and work piece .then electrode and work piece b/w magnetic field obtain.

8. Magnetic field Then those magnetic field are set up b/w work piece and electrode .then due to magnetic field are some deflect in magnetic field direction. These concept are use in forward and reverse welding. When electrode are move in magnetic field direction .then we called forward welding. Due to this welding we weld very thick material. When we move electrode in reverse dirction of magnetic field.then these type of welding we called revrse welding .due to this welding we can weld thin type of material.

10. Thank u