GATE PI 2002
GATE PI
1
The height of the down sprue is $$175$$ $$mm$$ and its $$CS$$ area at the base is $$200\,\,m{m^2}.$$ The $$CS$$ area of the horizontal runner is also $$200$$ $$m{m^2}$$. Assuming no losses, indicate the correct choice for the time (seconds) required to fill a mold cavity of volume $${10^6}\,\,m{m^3}.$$ (use $$g=10$$ $$m/{s^2}$$)
2
The permeability of molding sand was determined using a saturated $$AFS$$ sample by passing $$2000cc$$ of air at a gage pressure of $$10$$ $$g/c{m^2}$$. If the time taken for the air to escape was $$1$$ min, the permeability number is:
3
Proper gating design in metal casting
$$P:$$ Influences the freezing range of the melt
$$Q:$$ Compensates the loss of fluidity of the melt
$$R:$$ Facilitates top feeding of the melt
$$S:$$ Avoids misrun
4
A $$10$$ $$mm$$ thick steel bar is to be horizontally cast with two correctly spaced top risers of adequate feeding capacity. Assuming end effect without chill, what should be the theoretical length of the bar?
5

6
In spot pulsed laser welding of aluminium plates (density $$ = 2700kg/{m^3},$$ specific heat $$=896J/kg,$$ melting temp $$=933K,$$ latent heat of melting $$ = 398\,\,kJ/kg)$$ at a temp of $${30^ \circ }C,$$ pulse with energy of $$0.5J$$ is focused onto an area of $$0.05m{m^2}.$$ If the entire energy is coupled into the material, what will be the depth of weld assuming the $$CS$$ area of the weld is circular and is uniform throughout its depth and only heat conduction in the direction of penetration
7
Two different tools $$A$$ and $$B$$ having nose radius of $$0.6mm$$ and $$0.33mm$$ respectively are used to machine $$C-45$$ steel employing feed rate of $$0.2$$ $$mm/rev$$ and $$0.1mm/rev$$ respectively. The tool that gives better finish and the value of ideal surface roughness are
8
A cutting tool is designated in 'Orthogonal Rake System' as:
$$${0^ \circ } - {0^ \circ } - {6^ \circ } - {6^ \circ } - {25^ \circ } - {75^ \circ } - 0.8\,\,mm.$$$
The following data were given
$${S_0} = $$ feed $$=0.12$$ $$mm/rev$$
$$T=$$ depth of cut $$=2.0$$ $$mm$$
$${a_2} = $$ chip thickness $$=0.22$$ $$mm$$
$${V_f} = $$ chip velocity $$=52.6$$ $$m/min$$
$${\tau _s} = $$ dynamic yield shear strength $$=400$$ $$MPa$$
$${P_z} = $$ main cutting force $$ = {S_0}\,t\,{\tau _s}\left( {\zeta \,\sec y - \tan \gamma + 1} \right)$$
The following data were given
$${S_0} = $$ feed $$=0.12$$ $$mm/rev$$
$$T=$$ depth of cut $$=2.0$$ $$mm$$
$${a_2} = $$ chip thickness $$=0.22$$ $$mm$$
$${V_f} = $$ chip velocity $$=52.6$$ $$m/min$$
$${\tau _s} = $$ dynamic yield shear strength $$=400$$ $$MPa$$
$${P_z} = $$ main cutting force $$ = {S_0}\,t\,{\tau _s}\left( {\zeta \,\sec y - \tan \gamma + 1} \right)$$
Where $$\zeta = $$ chip reduction coefficient and $$\gamma = $$ orthogonal rake.
The main cutting force $$\left( {{P_z}} \right)$$ and cutting power assuming orthogonal machining are
9
A $$31.8MM$$ $$HSS$$ drill is used to drill a hole in cast iron block $$100$$ $$mm$$ thick at cutting speed of $$n20m/min$$ and feed $$0.3min/rev.$$ If the over travel of drill is $$4mm$$ and approach $$9mm,$$ the time required to drill hole is
10
Match GROUP - I with GROUP - II
11
A side and face cutter $$125mm$$ diameter has $$10$$ teeth. It operates at a cutting speed of $$14m/min$$ with a table traverse $$100mm/min.$$ The feed per tooth of the cutter is
12
A cup of $$10$$ $$cm$$ height and $$5$$ $$cm$$ diameter is to be made from a sheet metal of $$2mm$$ thickness. The number of deductions necessary will be
13
In sheet metal working, the spring back increase when
$$P:$$ Ratio of bend radius to sheet thickness is small
$$Q:$$ Young's modulus of the sheet is low
$$R:$$ Yield strength of the sheet is high
$$S:$$ Tension is applied during bending
$$P:$$ Ratio of bend radius to sheet thickness is small
$$Q:$$ Young's modulus of the sheet is low
$$R:$$ Yield strength of the sheet is high
$$S:$$ Tension is applied during bending