In an orthogonal cutting operation on a work piece of width $$2.5mm,$$ the uncut chip thickness was $$0.25$$ $$mm$$ and the tool rake angle was $$0$$(zero) degrees. It was observed that the chip thickness was $$1.25mm.$$ The cutting force was measured to be $$900N$$ and the thrust force was found to be $$450N.$$ Find the mean shear strength of the work piece material and if the coefficient of friction between the chip and the tool was $$0.5,$$ what is the machining constant.

The effect of rake angle on the mean friction angle in machining can be explained by

A low carbon steel is to be welded by the manual metal arc welding process using a linear $$V$$-$$I$$ characteristic $$DC$$ power source.

The following data is available.
$$O.C$$ voltage of the power source $$=62V,$$
$$S.C$$ current for the setting used $$=130A,$$
ARC length $$=4mm,$$
Traverse speed of welding $$=15cm/min$$
Efficiency of heat input $$ = 85\% $$
The relation between the arc length $$L$$ in $$mm$$
and arc voltage $$V$$ is $$V=20+1.5L$$
Calculate the heat input into the work piece.

For resistance spot welding of $$1.5$$ $$mm$$ thick steel sheets, the current required is of the order