For turning $$NiCr$$ alloy steel at cutting speeds of $$64m/min$$ and $$100m/min,$$ the respective tool lives are $$15min$$ and $$12$$ $$min.$$ The tool life for a cutting speed of $$144m/min$$ is

During orthogonal cutting of mild steel with a $$10$$ degrees rake angle tool the chip thickness ratio was obtained as $$0.4.$$ The shear angle (in degrees) evaluated from this data is

resistance spot welding is performed on two plates of $$1.5$$ $$mm$$ thickness with $$6$$ $$mm$$ diameter electrode, using $$15000$$ $$A$$ current for a time duration of $$0.25sec$$. assuming the interface resistance to be $$0.0001\Omega ,$$ the heat generated to form the weld is

Two plates of the same metal having equal thickness are to be butt welded with electric arc. When the plate thickness changes, welding is achieved by