1. Hardenability of steel is a measure of
(A) the ability to harden when it is cold worked
(B) the maximum hardness that can be obtained when it is austenitized and then quenched
(C) the depth to which required hardening is obtained when it is austenitized and then quenched
(D) the ability to retain its hardness when it is heated to elevated temperatures
2. The fluidity of molten metal of cast alloys (without any addition of fluxes) increases with increase in
(B) surface tension
(C) freezing range
(D) degree of superheat
3. The cold forming process in which a hardened tool is pressed against a workpiece (when there is relative motion between the tool and the workpiece) to produce a roughened surface with a regular pattern is
(A) Roll forming
(B) Strip rolling
4. The most common limit gage used for inspecting the hole diameter is
(A) Snap gage
(B) Ring gage
(C) Plug gage
(D) Master gage
5. In an electrical discharge machining process, the breakdown voltage across inter electrode gap (IEG) is 200 V and the capacitance of the RC circuit is 50 μF. The energy (in J) released per spark across the IEG is____
6. The binary phase diagram of metals P and Q is shown in the figure. An alloy X containing 60% P and 40% Q (by weight) is cooled from liquid to solid state. The fractions of solid and liquid (in weight percent) at 1250 °C, respectively, will be
(A) 77.8% and 22.2%
(B) 22.2% and 77.8%
(C) 68.0% and 32.0%
(D) 32.0% and 68.0%
7. The figure shows a pouring arrangement for casting of a metal block. Frictional losses are negligible. The acceleration due to gravity is 9.81 m/s2. The time (in s, round off to two decimal places) to fill up the mold cavity (of size 40 cm × 30 cm × 15 cm) is____
8. A gas tungsten arc welding operation is performed using a current of 250 A and an arc voltage of 20 V at a welding speed of 5 mm/s. Assuming that the arc efficiency is 70%, the net heat input per unit length of the weld will be ______ kJ/mm (round off to one decimal place).
9. The thickness of a sheet is reduced by rolling (without any change in width) using 600 mm diameter rolls. Neglect elastic deflection of the rolls and assume that the coefficient of friction at the roll-workpiece interface is 0.05. The sheet enters the rotating rolls unaided. If the initial sheet thickness is 2 mm, the minimum possible final thickness that can be produced by this process in a single pass is ______ mm (round off to two decimal places).
10. A through hole is drilled in an aluminum alloy plate of 15 mm thickness with a drill bit of diameter 10 mm, at a feed of 0.25 mm/rev and a spindle speed of 1200 rpm. If the specific energy required for cutting this material is 0.7 N·m/mm3, the power required for drilling is ______ W (round off to two decimal places).
11. In an orthogonal machining with a single point cutting tool of rake angle 10°, the uncut chip thickness and the chip thickness are 0.125 mm and 0.22 mm, respectively. Using Merchant’s first solution for the condition of minimum cutting force, the coefficient of friction at the chip-tool interface is ______ (round off to two decimal places).