Which of the following is the most wear resistant grade of carbide used for the cutting tools?
Aluminium carbide
Tungsten carbide
Nickel carbide
Iron carbide
Correct Answer :
B. Tungsten carbide
Related Questions
Biological shield in a nuclear reactor is generally provided to protect against the
α-rays
β-rays
Gamma rays & neutrons
Electrons
Which of the following materials does not form adherent oxide film on surface?
Copper
Nickel
Aluminium
Gold & silver
In a drilling process, the metal is removed by both shearing & extrusion. General purpose drills are made of
Stainless steel
Mild steel
High speed steel
High carbon steel
In case of brasses, with decreasing zinc percentage and increasing copper percentage, its __________ increases.
Percentage elongation
Brinell hardness
Tensile strength
All 'a', 'b' & 'c'
Dislocations are __________ defects.
Point
Line
Volume
None of these
Depreciation of machines fails under the indirect expenses head. As per income tax regulations, it is calculated by the __________ method.
Diminishing balance
Sinking fund
Multiple straight line
Sum of the years digit
Pearlite comprises of
87% cementite & 13% Fe
87% ferrite & 13% cementite
93.33% ferrite & 6.67% C
87% ferrite & 13% C
Reduction in the grain size reduces the __________ of the material.
Fatigue resistance
Tensile strength
Creep resistance
All (A), (B) & (C)
Which of the following is prone to cup and cone fracture?
Cast iron
Soft brass
Round specimen of ductile metal
Flat tensile specimen of ductile metal
The bolt is subjected to __________ when the nut is tightened by putting the washer beneath it.
Tension
Shear
Compression
Bending & tension
A material in which the atoms are arranged regularly in some directions but not in others, is termed as 'mesomorphous material'; an example of which is
Lead
Glass
Mica
Silver
The critical pressure at which the latent heat of vaporisation of steam becomes zero is __________ Kg/cm2.
273.15
225.65
100.03
373.15
Fibre reinforced plastic (FRP) are
Made of glass fibre and thermoplastic resins
Anisotropic
Made of thermosetting resin and glass fibre
Both 'b' & 'c'
The most important consideration, while designing the refrigeration system of an aircraft is that the refrigeration system
Is as light as possible
Has very high C.O.P.
Employs minimum quantity of refrigerant
Consumer minimum horse power
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
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
Pick out the wrong statement.
For a pressure vessel to be classified as 'thin vessel', the ratio of wall thickness to mean radius is less than 0.1
For calculating forces and efficiency of riveted joint, either rivet diameter or rivet hole diameter is used in case of pressure vessel and in structural work
Longitudinal joint is normally made butt joint to maintain the circularity of the vessel
Maximum diameter of the opening provided in a pressure vessel, which does not require any compensation is 200 mm
Ganister contains maximum percentage of
FeO
SiO2
MgO
MnO2
Thermal diffusivity of a substance is proportional to (where, k = Thermal conductivity)
1/k
k
k2
1/k2
A dense structure of grinding wheel is not used for the
Ductile material
Hard materials
Brittle materials
Finishing cuts
Tin based white metals are used, where bearings are subjected to
High pressure & load
Low pressure & load
High temperature
Large surface wear
Basic open hearth furnace (BOF) is not used for producing __________ steel.
Killed
Rimming
High alloy
None of these
With decrease in the grain size of a material, its creep resistance
Increases
Decreases
Remain constant
Either (A) or (B); depends on the material
__________ of grey cast iron produces white cast iron.
Tempering
Rapid heating
Rapid cooling
Slow cooling
Pressure exerted by a liquid depends upon its
Surface tension
Density
Viscosity
Buoyancy
Babbitt lining is used on brass/bronze bearings to increase the
Antifriction properties
Compressive strength
Bearing resistance
Wear resistance
There are one octahedral void and __________ tetrahedral void in the closest packing of atoms.
One
Two
Three
None of these
For dynamic strain measurement, the Wheatstone bridge used is of __________ type.
Voltage sensitive null
Voltage sensitive deflected
Current sensitive deflected
None of these
Ultimate strength in tension as compared to that in shear for steel is
Half
One third
One and half times
One fourth
Pick out the wrong statement.
Cold cracking of a weld is due to the presence of hydrogen gas in the weld
True stress is given by, σ = σE (1 + εE), where σE and εE are engineering stress and engineering strain respectively
Phosphorous can be easily recovered in the iron blast furnace
High residual stress at the surface is beneficial for fatigue properties of a material