Other parameters remaining same, the recrystallisation temperature of an alloy is lowered, when
Strain rate is increased
Grain size is increased
Prior cold deformation is increased
Not affected by any of the above parameters
Correct Answer :
A. Strain rate is increased
Related Questions
Tesla metre per ampere (T. m/A) is the unit for the measurement of
Magnetic susceptibility
Magnetic moment
Permeability of free space
Flux density
A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C.
50
100
150
200
Frother is added in the froth floatation cell used in ore beneficiation to stabilise the air bubbles (i.e., froth), which will hold the ore particles, but it does not affect the floatability of minerals. Which of the following is not used as a frother?
Cresylic acid
Xanthaies
Pine oil
All 'a' 'b' & 'c'
With increase in temperature, the electrical conductivity of semiconductors
Increases
Decreases
Remain constant
Either (A) or (B), depends on the type of semi-conductor
Fatigue limit improvement by over stressing the metal by successively increasing the load is called coaxing. In fatigue failure, the material fails
Below the yield point
Above the yield point
Below the elastic limit
At the elastic limit
Pick out the wrong statement.
Ductile fracture of a stressed material, which exhibits a large plastic deformation is commonly caused by the formation and coalescence of voids in the necked region
Brittle fracture is caused by the propagation of pre-existing cracks in the material and involves minimum plastic deformation
Fatigue fracture of a material is always brittle in nature and takes place due to the existence of line imperfections
Brittle materials are generally tested in tension
An ideal material for making cooking vessels should have
High heat capacity
Low heat capacity
High thermal conductivity
Both (B) and (C)
When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the
Partial pressure of water vapour is less than the total pressure
Humidity is < 100% & dew point temperature of air has not reached
Dew point temperature of air has not reached & air is not saturated fully
Air is fully saturated
The most serious manufacturing defect from fracture toughness point of view is
Surface roughness
Pores
Spherical inclusion
Crack
Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore?
High fusibility & fluidity
High thermal conductivity
Low density
High chemical activity
Midrex process of sponge iron production uses reformed natural gas as the reducing agent, which uses iron ore in the form of
Lumps
Pellets
Briquettes
Sinter
Stainless steel is welded using
Oxy-acetylene flame
Oxy-hydrogen flame
Arc welding
Inert gas arc welding
Which of the following fastening devices has its both ends threaded?
Bolt
Stud
Set screw
Split nut
Secondary hardening in steels arises out of the
Precipitation of fine alloy carbides at high temperatures
Refinement of ferrite grain size by working
Decomposition of retained austenite upon heat treatment
Precipitation of complex inter-metallic upon heat treatment
The hardenability of steel decreases with
Decrease in dislocation density
Increase in solutionising temperature
Increase in strength
Decrease in grain size
The passage between the nozzle and the __________ is called 'sprue' in case of injection moulding.
Runner
Cylinder
Mold
None of these
The minimum carbon content in steel should be __________ percent for it to respond to a hardening treatment.
0.2
0.4
0.6
0.8
Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs?
Enthalpy
Relative humidity
Wet bulb temperature
Dew point temperature
Thermit welding uses the following energy source.
Electrical energy
Chemical energy
Energy of high velocity electrons
Heat generated by friction
Batch process is preferred over continuous process, when the
Product yields and quality cannot be achieved in continuous process, because of long residence time
Sales demand of product is not steady
Same equipment cannot be used for several processes of the same nature
All (A), (B) & (C)
Increase in the entropy of a system represents the
Degradation of energy
Decrease in system pressure
Increase in the availability of energy
Increase in the temperature
Alloys having more than 80% copper are generally more
Abrasion resistant
Corrosion resistant
Prone to season cracking
Machinable
Identify the correct statement with reference to the extractive metallurgy of aluminium.
The electrolyte consists of molten Na3AlF6 with approximately 1 to 8% Al2O3
Approximately 80% of the aluminium deposited on the cathode comes from cryolite
Sodium is deposited along with aluminium, but is immediately vaporised
Anode effect sets in when the cryolite concentration goes below 40%.
Gantt charts are used for streamlining the
Inventory control
Production schedule
Sales forecasting
Quality control
The emf of a Deniell cell Zn | Zn2+ || Cu2+ | Cu can be increased by
Decreasing the surface area of the electrodes
Increasing the concentration of zinc sulphate solution
Increasing the surface area of the electrodes
Increasing the concentration of copper sulphate solution
Energy of the sun arises mainly from __________ reactions.
Fusion
Fission
Combustion
None of these
Heat release during phase change is observed in case of a/an
Boiler
Condenser
Evaporator
All (A), (B) & (C)
Natural water contains approximately __________ percent of heavy water.
0.015
0.71
1.2
3.5
__________ property of steel increases by addition of large amount of silicon in it.
Mechanical
Machining
Magnetic
Refractory
The approximate height of a blast furnace having a useful volume of 2000 m3 is about __________ metres
25
35
55
75