During decarburising of a plain carbon steel, the thickness of ferrite layer growth is proportional to
Time
Square root of time
Square of time
Cube of time
Correct Answer :
B. Square root of time
Related Questions
Pearlite comprises of
87% cementite & 13% Fe
87% ferrite & 13% cementite
93.33% ferrite & 6.67% C
87% ferrite & 13% C
The main reducing agent in iron blast furnace is
Carbon dioxide
Carbon monoxide
Oxygen
Air
Constituents of stellite are
Zinc, copper & nickel
Cobalt, chromium & tungsten
Zinc, aluminium & nickel
Nickel, cobalt & vanadium
The substance used as a smoke screen in warfare is
C2H2
SiCl4
P2O5
PCl5
Catalyst used in the catalytic converter employed in automobiles to convert CO into CO2 and for complete oxidation of un-burnt hydrocarbons is
Nickel
Cobalt
Vanadium
Platinum
Adhesives
Cant be used in the form of pressure sensitive tapes
Cant join two dissimilar metals
Cure instantaneously after application on a surface
None of these
The most suitable material for die casting is
Iron
Copper
Steel
Nickel
Steel containing low percentage of nickel, chromium & tungsten are termed as the __________ steel.
Wrought
Tool
Alloy
Plain carbon
Evaporative cooling process employs a combination of cooling and humidification in which the
Sensible heat is added
Sensible heat is removed and the latent heat is added
Latent heat is removed
Sensible heat is added and latent heat is removed
Natural water contains approximately __________ percent of heavy water.
0.015
0.71
1.2
3.5
Maximum consumption of limestone is in the __________ industry.
Iron and steel
Cement
Glass
Fertiliser
L.D. (Linz-Donawitz) converter is used in the production of
Copper
Steel
Zinc
Aluminium
Oxyacetylene reducing flame is used while carrying out welding on
Alloy steel
Grey cast iron
Mild steel
High carbon steel
Hydrogen can be
Used in I.C. engines as fuel
Liquefied & stored under cryogenic conditions
Produced by electrolysis of water
All (A), (B) & (C)
On decreasing the grain size of a polycrystalline material, the property most likely to deteriorate is
Creep
Toughness
Tensile strength
Fatigue
__________ glass is used in the mercury in glass thermometer meant for measuring a temperature of 500°C.
Borosilicate
High silica
Supermax
Lead
Which of the following commonly used condenser tube materials has the lowest thermal conductivity?
Admiralty brass
Stainless steel
Aluminium brass
Titanium
The swift cup test evaluates the following property of a sheet metal.
Stretchability
Drawability
Bendability
None of these
The dew point temperature lines on psychrometric charts are straight inclined sloping downwards to the right. When relative humidity of moist air is 100%, then
Wet bulb temperature=dry bulb temperature
Wet bulb temperature=dew point temperature
Saturation temperature=dew point temperature
All 'a', 'b' & 'c'
Dry saturated steam can be converted into superheated steam by
Increasing its cross-sectional area of flow
Passing it through a pressure reducing valve
Forcing it downwards through a vertical tube
None of these
A jig is used while __________ a hole.
Boring
Counter boring
Drilling
Enlarging
In fluid flow, and heat and mass transfer, one encounters (i) kinematic velocity (μ), (ii) molecular diffusivity (θ) and thermal diffusivity (α). The units of these quantities are.
μ , α and θ all have units of m/s
μ , α and θ all have units of m2/s
α and θ have units of m2/s, while μ has unit of m/s
α and θ have units of m/s, while μ has unit of m2/s
Gas turbine normally employs a constant __________ cycle.
Pressure
Temperature
Volume
None of these
The thermodynamic law, 
= constant, is not followed by the
Free expansion of an ideal gas
Adiabatic expansion of steam in turbine
Adiabatic compression of air
Ideal compression of air
Steel is welded using the __________ flame.
Carburising
Neutral
Oxidising
All (A), (B) & (C)
Current employed in resistance welding ranges from __________ kVA/
.
1.2 to 2.5
4.5 to 6.2
7.5 to 8.5
10.5 to 15.5
In inventory control theory, the economic order quantity (EOQ) is the
Lot size corresponding to break even analysis
Average level of inventory
Optimum lot size
None of these
The minimum and the maximum number of members required to form a Private Limited Joint Stock Company are respectively
7 and 30
10 and 50
2 and 50
13 and 55
Name the safety device used to protect the boiler, when the water level falls below a minimum level.
Blow down valve
Blow off cock
Fusible plug
Safety valve
Out of the following, the best material capable of withstanding shock & vibration without the danger of cracking is
Malleable iron
Grey cast iron
Chilled cast iron
White cast iron