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

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

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 (Joules) dissipated to the base metal will be (neglecting all other heat losses)

Diamond cutting tools are not recommended for machining of ferrous metals due to