When carbon in the cast iron is principally in the form of graphite, the cast iron will be of
Brown colour
Yellow colour
White colour
Grey colour
Correct Answer :
D. Grey colour
Related Questions
A chain drive transmits __________ power as compared to belt drive.
More
Less
Same
None of these
In a hydrodynamic lubricated bearing
There is a thick film of lubricant between the journal and the bearing
There is a thin film of lubricant between the journal and the bearing
The lubricant is forced between the journal and the bearing, by external pressure
There is no lubricant between the journal and the bearing
If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation
124 d
138 d
151 d
168 d
The permissible stress in the fillet weld is 100 N/mm². The fillet weld has equal leg lengths of 15 mm each. The allowable shearing load on the weldment per cm length of the weld is
7.5 kN
10.6 kN
15 kN
22.5 kN
The bending moment M and a torque T is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then M is equal to
T/2
T
2T
4T
Stress concentration factor is defined as the ratio of
Maximum stress to the endurance limit
Nominal stress to the endurance limit
Maximum stress to the nominal stress
Nominal stress to the maximum stress
The permissible stress for carbon steel under static loading is generally taken as
2000-3000 kg/m²
3000-4000 kg/cm²
4000-4500 kg/cm²
7500-10,000 kg/cm²
The efficiency of a square threaded screw is maximum if the helix angle is equal to (Where φ = Angle of friction)
90° - φ
45° - φ
45° - φ/2
45° + φ/2
Fabric belts are used in industrial applications because
They are cheap
They can work at high temperature
They are unaffected by moisture and humidity
None of the above
For a bevel gear having the pitch angle θ, the ratio of formative number of teeth (TE) to actual number of teeth (T) is
1/sinθ
1/cosθ
1/tanθ
sinθ cosθ
When two helical springs of equal lengths are arranged to form a cluster spring, then
Shear stress in each spring will be equal
Load taken by each spring will be half the total load
Only A is correct
Both A and B is correct
Lewis equation in gears is used to find the
Tensile stress in bending
Shear stress
Compressive stress in bending
Fatigue stress
The notch angle of the Izod impact test specimen is
10°
20°
30°
45°
A type of brake commonly used in motor cars is a
Shoe brake
Band and block brake
Band brake
Internal expanding brake
The crest diameter of a screw thread is same as
Major diameter
Minor diameter
Pitch diameter
Core diameter
When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
Axially upwards
Axially downwards
Axially upwards or downwards
None of these
The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80° for
Reducing stress concentration
Ease of manufacture
Safety
Fullering and caulking
When two nonintersecting and non-coplanar shafts are connected by gears, the arrangement is known as
Spur gearing
Helical gearing
Bevel gearing
Spiral gearing
A machine part subjected to __________ is called a strut.
An axial compressive force
A tangential force
An axial tensile force
Any one of these
In nitrated parts, the origins of the fatigue cracks will occur at
Surface
Just below the surface
Within the core
None of the above
The allowable static stress for steel gears is approximately __________ of the ultimate tensile stress.
One-fourth
One-third
One-half
Double
Crushing resistance required to crush the rivet per pitch length is
p.d.σc
p.t.σc
n.d.t.σc
(p - d) t.σc
The effective stress in wire ropes during normal working is equal to the stress due to
Axial load plus stress due to bending
Acceleration/retardation of masses plus stress due to bending
Axial load plus stress due to acceleration/retardation
Bending plus stress due to acceleration/retardation
A circular shaft can transmit a torque of 5 kN-m. If the torque is reduced to 4 kN-m, then the maximum value of bending moment that can be applied to the shaft is
1 kN-m
2 kN-m
3 kN-m
4 kN-m
In worm gears, the pressure angle is ________ the angle between two inclined faces in axial plane.
Half
Twice
Thrice
None of these
The largest diameter of an external or internal screw thread is known as
Minor diameter
Major diameter
Pitch diameter
None of these
The dedendum is the radial distance from the
Pitch circle to the top of a tooth
Pitch circle to the bottom of a tooth
Top of a tooth to the bottom of a tooth
Addendum circle to the clearance circle
Silver based solder is used for
Flaring
Brazing
Soft soldering
Fusion welding
At low temperatures (say 75°C) the notched bar impact value of steel
Increases markedly
Decreases markedly
Remain same
Depends on heat treatment carried out
A universal coupling is used to connect two shafts
Which are not in exact alignment
Which are perfectly aligned
Whose axes intersect at a small angle
Have lateral misalignment