GATE PI 1989
GATE PI
1
Negative allowance is provided on the pattern to take care of
2
Molten aluminium was poured in a sand mold and the thickness of solid skin formed after $$20$$ seconds and $$50$$ seconds were fond to be $$3mm$$ and $$4.5mm$$ respectively. What would be the thickness of the solid skin at the end of $$100$$ seconds after pouring?
3
What is the velocity of the steel at the bottom of the sprue if the sprue height is $$30$$ $$cm$$? Assume the frictional and other losses to be $$20\% $$
4
Shrinkage allowance on pattern is provided to compensate for shrinkage when
5
Green strength in powder metallurgy refers to the strength of
6
The process by which shell like castings (like toys) are made is
7
Poor collapsibility of the mold leads to .......... type of casting defect in aluminium castings.
8
For the same material, powder metallurgy process is superior to casting for
9
In welding brass with oxy-acetylene flame, the type of flame used is
10
Match the following
11
In welding a mild steel sheet using an oxy-acetylene flame, the total amount of acetylene consumed was $$8.0$$ liters the oxygen consumption from the cylinder is
12
If the $$z$$-axis & $$x$$-axis of $$CNC$$ lathe are provided with straight line controls, it is possible to carry out
13
Match the following
14
If the number of double strokes per minute in a shaper is calculated by ($$0.643\, \times \,$$ Cutting speed in $$mm/min$$) / length of the stroke in $$m,$$ then the return speed is faster than the cutting speed by
15
In turning operation the surface finish can be improved by decreasing
16
Abrasives are not used in
17
The results of machining steel with $$2$$ grades of tool material are given below. For a $$180$$ $$min.$$ Tool life which tool is recommended and why?
If the tool regrinding and changing time is $$15min,$$ the cutting speed for tool $$A$$ $$ahs$$ to be chosen ($$40m/min$$ or $$50m/min$$)
18
Calculate the tonnage capacity of the broaching machine required to broach on the hole under the following conditions.
Diameter of the finished hole $$=75mm,$$
rise per tooth $$=0.03mm$$
Tooth pitch $$=10mm,$$
Length of the broach $$=750mm$$
Cutting speed $$=6m/min,$$
specific cutting pressure $$ = 1300 \times {t^{0.4}}\,\,N/m{m^2},$$ (Where $$t$$ is the uncut chip thickness)
If the tool and work handling time is $$0.5min,$$ estimate the production rate per hour
Diameter of the finished hole $$=75mm,$$
rise per tooth $$=0.03mm$$
Tooth pitch $$=10mm,$$
Length of the broach $$=750mm$$
Cutting speed $$=6m/min,$$
specific cutting pressure $$ = 1300 \times {t^{0.4}}\,\,N/m{m^2},$$ (Where $$t$$ is the uncut chip thickness)
If the tool and work handling time is $$0.5min,$$ estimate the production rate per hour
19
In $$HSS,$$ the tungsten can be substituted by
20
In a wire drawing operation diameter of $$6mm$$ is reduced in stages to a diameter of $$1.34mm.$$ Assuming ideally rigid plastic material and ideally lubricant condition,
$$i)$$$$\,\,\,\,\,\,\,$$ The minimum number of passes required by assuming max reduction per pass
$$\,\,\,\,\,\,\,\,\,\,\,\,$$ is obtained with $$\mu = 0.2$$ and half die angle as $${6^0}$$. If the flow strength of the
$$\,\,\,\,\,\,\,\,\,\,\,\,$$ material is $$60$$ $$MPa.$$
$$i)$$$$\,\,\,\,\,\,\,$$ The minimum number of passes required by assuming max reduction per pass
$$\,\,\,\,\,\,\,\,\,\,\,\,$$ is obtained with $$\mu = 0.2$$ and half die angle as $${6^0}$$. If the flow strength of the
$$\,\,\,\,\,\,\,\,\,\,\,\,$$ material is $$60$$ $$MPa.$$
$$ii)$$$$\,\,\,\,\,$$ The diameter of wire after $${2^{nd}}$$ stage
21
At the last hammer stroke the excess material from the finishing cavity of a forging die is pushed into .............
22
The blank diameter used in thread rolling will be
23
Collapsible tubes are made by
24
Outside diameter of bush is turned using a mandrel. The mandrel diameter is maintained as $${30^{\matrix{
{ + 0.000} \cr
{ - 0.050} \cr
} }}\,\,mm$$ and the bore diameter is $${30^{\matrix{
{ + 0.050} \cr
{ - 0.000} \cr
} }}\,\,mm$$. The maximum value in $$mm$$ of the eccentricity on the bush due to the locating mandrel
25
Flatness of slip gages is checked with