A weld is made using $$MIG$$ welding process with the following welding parameters: Current: $$200A;$$ Voltage: $$25V;$$ Welding speed: $$18$$ $$cm/min;$$ wire diameter: $$1.2$$ $$mm;$$ Wire feed rate: $$4$$ $$m/min;$$ Thermal efficiency of the process: $$65\% $$

The area of cross section of weld bead in $$m{m^2}$$ is:

Two plates with symmetrical $$V$$ joint penetration of $$V$$ angle $$60deg$$ are to be arc welded in a single pass. The power $$P(kW)$$-arc length $$L$$ $$(mm)$$ characteristic is given by $$P=4+0.8L-0.1$$$${L^2}$$. Assuming that the top surface of the weld is flat & flush with the plate top surface, & the energy losses are $$20\% $$, the density of filler material is $$8gm/cc$$ and the energy required to melt $$1$$ $$gm$$ is $$1400$$ joules. The plate dimensions are $$1000mm$$ length & $$5mm$$ thickness. The maximum welding speed is .......................

The voltage-arc length characteristics of a power source is $$V=20+40L,$$ where $$V=$$ operating voltage in volts and $$L=$$ arc length in $$cm.$$ The open circuit voltage and short circuit current for arc lengths ranging from $$3$$ to $$5mm$$ and current from $$400$$ to $$500$$ amps during welding operation are

Two sheets of low carbon steel $$1.5mm$$ thick each are spot welded by passing a current $$10000$$ amps for $$5$$ cycles in $$50$$ $$Hz$$ main supply.

i) What is the heat generated due to the supply of power if effective resistance has $$200$$ micro ohms,

ii) The maximum indentation is $$10\% $$ of sheet thickness and density of the spot weld nugget $$8$$ $$gm/cc.$$ If $$1380$$ Joules are required to melt $$1gm$$ of steel, determine heat required for welding operation if $$D=6SQRT$$ $$(t)$$ to determine nugget diameter $$D$$ and assume the nugget size to be equal to metal between the two electrodes