The optimum pouring time for a casting depends on several factors. One important factor among them is

A rectangular block of steel $$C.S$$ $$100\,\, \times \,\,150mm$$ and $$250mm$$ height is to be cast with out any riser. The block is moulded entirely in the drag of a green sand flask & is tap gated. The cope of the flask is $$200mm$$ height & the height of the metal during pouring is $$100mm$$ above the cope level. A tapered sprue is employed & the gating ratio is $$1:4:2$$. Assume no energy losses in the system. The time taken (in seconds) to fill the casting cavity, if the tapered sprues with $$500$$ $$m{m^2}$$ exit area is used.

Low permeability molds and low pouring temperature of the molten metal causes ......................... defect in castings.

Pressure die casting deals with casting metals of relatively ............. A ............. melting point and provides ........ B.......... production rate.

A. higher / lower,$$\,\,\,\,\,\,\,\,\,\,$$ B. higher / lower

Ceramic slurry is used in making the molds for

The voltage-arc length characteristic of a $$DC$$ arc is given by $$V=20+40L.$$ where $$L=$$ arc length in $$cm.$$ The power source characteristics can be approximated by a straight line. Open circuit is $$80V$$ and short circuit current $$1000$$Amps. The optimum arc length in $$mm$$

A resistance welder is rated at $$50$$ $$kVA,$$ at $$50\% $$ duty cycle. Secondary voltage is always constant at $$25$$ volts. If a job requires $$1500$$Amps current, determine the maximum welding time in a total cycle time of $$30$$$$secs$$.

In welding process, penetration is increased by

....................... is the non-fusion method of joining dissimilar metals with metals whose melting temp is greater than $${400^ \circ }C$$.

In spot welding of aluminium sheets, the welding current should be .........A........ and weld time should be kept ............B......... than for $$MS$$ sheet of same thickness.

(A). higher / lower, (B). higher / lower

High alloy steel components are preheated before welding for reducing

Continuous rails for Indian railways are welded by ........ Welding process.

Thrust force in drilling can be reduced by .................A............... the point angle and by ..........B.......... the helix angle of the drill

(a) increasing / reducing
(b) increasing / reducing

Feed motion can be provided with stepper motors in $$CNC$$

A drilling machine has to be designed with $$8$$ spindle speeds ranging approximately between $$120$$ to $$1200$$ $$rpm.$$ The $${5^{th}}$$ spindle speed is

Amount of energy consumption per unit volume of metal removal is maximum in

The teeth of both external and internal spur gears can be cut on

During orthogonal turning a steel rod at feed $$0.25$$ $$mm$$ per revolution and depth of cut $$4.00$$ $$mm$$ by a tool of geometry $${0^0},\, - {10^0},\,\,{8^0},\,\,{7^0},\,\,{15^0},\,\,{60^0},\,\,0\,\,(mm)\,\,;$$ the following observation were made: Tangential force $$=1,600N,$$ Axial force in feed direction $$=800$$ $$N,$$ Chip thickness $$=0.60$$ $$mm.$$ Find the coefficient of friction between chip tool interface and shear strength of work material from shear force.

Amount of energy consumption for unit volume of metal removal is maximum in

Increase in rake angle causes ..........A................ in chip thickness and .............B......... in shear angle

(a) increase / reduction
(b) increase / decrease

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

In .................. A ................. operation the diameter of the desired hole will be smaller than the diameter of the .................... B ......................

A. blanking / piercing
B. punch / die

In progressive die (for sheet metal), spring loaded stripper plate is used to clamps the stock until:

At $${1000^ \circ }C$$ the crystallographic structure of iron is ....................

Seamless long steel tubes are manufactured by rolling, drawing and .............

The combination of slip gauges to obtain a dimension of $$10.35$$ $$mm$$ will be

Abbe's principle of alignment states that the scale axis must coincide with the line of

For angle measurement in metrology, the following pair can be used in conjunction with each other

Outside micrometer is calibrated with the help of