Electric Resistance Welding Methods

Electric resistance welding is a welding technique where metals are joined by applying pressure and heat generated by an electric current. There are several methods of electric resistance welding, which include:

1. Percussion welding
2. Seam welding
3. Flash welding
4. Electro slag welding

Explanation

The question asks which of the following is not an electric resistance method of welding. The correct answer is option A, i.e., electro slag welding. Here's why:

1. Percussion Welding: In percussion welding, two metals are joined by applying pressure and heat generated by rapidly striking them together. The heat generated by the impact is used to soften the metals, which are then joined together. This method is commonly used to weld wires, rods, and tubes.

2. Seam Welding: Seam welding is a process where two sheets of metal are joined by applying pressure and heat generated by an electric current. The current passes through the sheets, producing resistance heating, which melts the metal and fuses it together. This method is commonly used in the automotive industry to weld body panels together.

3. Flash Welding: Flash welding is a process where two metals are joined by applying pressure and heat generated by an electric current. The current is passed through the metals, producing resistance heating, which melts the surfaces of the metals. The surfaces are then forced together, producing a strong bond. This method is commonly used to weld rails, pipes, and other large structures.

4. Electro Slag Welding: Electro slag welding is a process where two metals are joined by melting them with an electric arc between the metals and a consumable electrode. The arc is shielded by a bed of molten slag, which prevents oxidation and stabilizes the arc. This method is commonly used to weld thick sections of steel in shipbuilding, bridge construction, and other heavy industries.

Conclusion

In conclusion, electric resistance welding is a popular welding technique that uses an electric current to generate heat and pressure to join two metals together. While there are several methods of electric resistance welding, electro slag welding is not one of them.