Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 5-6)

 Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 5-6)

5. With the decrease of electrode extension:

 Electrical resistance decreases

 Bead width increases

 More forceful arc

 All three options (a, b, and c) are correct

D

Electrode extension, also known as length of stick out, is the distance between the end of the contact tube 

and the end of the electrode. 

 An increase in electrode extension results in an increase in electrical resistance. 

 This causes resistance heating of electrode extended length, 

resulting in additional heat generation and increase of electrode melting rate. 

 But the energy so consumed reduces the power delivered to the arc thus decreases

 bead width and penetration depth.

1 point

6. Effect of welding speed (w) on melting efficiency?

 With increase of w, melting efficiency increase

 With decrease of w, melting efficiency increase

 W has no effect on melting efficiency

 All of these

A

NEXT ANSWER