In open die forging, a disc of diameter $$200mm$$ height $$60mm$$ is compressed without any barreling effect. The final diameter of the disc is $$400mm.$$ The true strain is

Match the correct combination for following metal working processes.

Which of the following is a solid state welding process.

A $$DC$$ welding machine with a linear power source characteristic provides open circuit voltage of $$80V$$ and short circuit current of $$800A,$$ during welding with the machine , the measured are current is $$500A$$ corresponding to an arc length of $$5.0$$ $$mm$$ and the measured are current $$460A$$ corresponding to an arc length of $$7.0$$ $$mm.$$ The linear voltage $$(E)$$ & arc length $$(L)$$ characteristic of the welding arc can be given as (where $$E$$ is in Volts and $$L$$ is in $$mm$$)