Resistance spot welding of two steel sheets is carried out in lap joint configuration by using a welding current of $$3$$ $$KA$$ and a weld time of $$0.2s.$$ A molten weld nugget of volume $$20m{m^3}$$ is obtained. The effective contact resistance is $$200\mu \Omega .$$ The material properties of steel are given as (i) latent heat of melting $$1400$$ $$kJ/kg,$$ (ii) density $$8000$$ $$kg/{m^3},$$ (iii) melting temp $${1520^ \circ }C$$, (iv) specific heat $$0.5$$ $$kJ/kgC.$$ The ambient temp is $$20C.$$

Heat (in Joules) used for producing weld nugget will be (assuming $$100\% $$ heat transfer efficiency

Autogeneous gas tungsten arc welding of a steel plate is carried out with welding current of $$500A,$$ voltage of $$20V,$$ and weld speed of $$20mm/min.$$ Consider the heat transfer efficiency from the arc to the weld pool as $$90\% $$. The heat input per unit length (in $$kJ/mm$$) is

The total angular movement (in degrees) of a lead screw with a pitch of $$5.0mm$$ to drive the work table by a distance of $$200mm$$ in a $$NC$$ machine is

A titanium sheet of $$5.0mm$$ thickness is cut by wire cut $$EDM$$ process using a wire of $$1.0mm$$ diameter. A uniform spark gap of $$0.5mm$$ on both sides of the wire is maintained during cutting operation. If the feed rate of the wire into the sheet is $$20mm/min,$$ the material removal rate (in $$m{m^3}/\min $$) will be