For hardening alloy steels and high speed steels, they are heated to
1100 to 1300°C
1300 to 1500°C
500 to 600°C
700 to 900°C
Correct Answer :
A. 1100 to 1300°C
Related Questions
A crankshaft is a __________ shaft.
Transmission
Machine
Machine frame
None of these
The shear stress in a beam varies from zero at the outer fibres to a maximum at the________.
Neutral surface
Upper surface
Lower surface
None of these
Which of the following formula is used in designing a connecting rod?
Euler's formula
Rankine's formula
Johnson's straight line formula
Johnson's parabolic formula
The maximum efficiency of a square threaded screw is
(1 - sinφ)/ (1 + sinφ)
(1 + sinφ)/ (1 - sinφ)
(1 - sinφ)/ (1 + cosφ)
(1 + cosφ)/ (1 - sinφ)
The shear plane in case of bolts should
Be across threaded portion of shank
Be parallel to axis of bolt
Be normal to threaded portion of shank
Never be across the threaded portion
Which of the following property is essential for spring materials?
Stiffness
Ductility
Resilience
Plasticity
A key made from a cylindrical disc having segmental cross-section, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
Wire ropes as compared to cotton ropes
Are lighter in weight
Offer silent operation
Can withstand shock loads
All of these
The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is
0.01 micron
0.1 micron
1 micron
10 microns
The contact ratio is the ratio of
Length of arc of recess to the circular pitch
Length of path of contact to the circular pitch
Length of arc of contact to the circular pitch
Length of arc of approach to the circular pitch
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
The plasticity is the property of a material which enables it to
Regain its original shape after deformation when the external forces are removed
Draw into wires by the application of a tensile force
Resist fracture due to high impact loads
Retain deformation produced under load permanently
The fatigue stress concentration factor is defined as
The ratio of endurance limit with stress concentration to the endurance limit without stress concentration
The ratio of endurance limit without stress concentration to the endurance limit with stress concentration
The product of the endurance limits with and without stress concentration
All of the above
The ball bearings are provided with a cage
To reduce friction
To facilitate slipping of balls
To prevent the lubricant from flowing out
To maintain the balls at a fixed distance apart
Rankine's theory of failure is applicable for following type of materials
Brittle
Ductile
Elastic
Plastic
Cold working
Increases the fatigue strength
Decreases the fatigue strength
Has no influence on fatigue strength
Alone has no influence on fatigue strength
A steel containing 0.8% carbon is known as
Eutectoid steel
Hypereutectoid steel
Hypo-eutectoid steel
None of these
An open belt drive is used when
Shafts are arranged at right angles and rotate in one definite direction
Shafts are arranged parallel and rotate in the opposite directions
Shafts are arranged parallel and rotate in the same directions
Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
According to Indian standards, total numbers of fundamental deviations are
10
15
20
25
Which of the following screw thread is adopted for power transmission in either direction?
Acme threads
Square threads
Buttress threads
Multiple threads
Two shafts will have equal strength, if
Diameter of both the shafts is same
Angle of twist of both the shafts is same
Material of both the shafts is same
Twisting moment of both the shafts is same
When the fulcrum is in between the load and effort, the lever is said to be of
First type
Second type
Third type
Any one of these
When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
2WD3n/Gd⁴
4WD3n/Gd⁴
8WD3n/Gd⁴
16WD3n/Gd⁴
In designing a flange coupling, the pitch circle diameter of bolts is taken as (where d = Diameter of the shaft)
2d
3d
4d
5d
In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)
T₁/T₂ = μθ × n
T₁/T₂ = (μθ)n
T₁/T₂ = [(1 - μ tanθ)/ (1 + μ tanθ)]n
T₁/T₂ = [(1 + μ tanθ)/ (1 - μ tanθ)]n
When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
4F/ πd²
6F/ πd²
8F/ πd²
16F/ 3πd²
The ball bearings are, usually, made from
Low carbon steel
High carbon steel
Medium carbon steel
High speed steel
The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
12
14
18
24
In a flange coupling, the flanges are coupled together by means of
Bolts and nuts
Studs
Headless taper bolts
None of these
The radial distance of a tooth from the pitch circle to the top of the tooth is called
Addendum
Dedendum
Clearance
Working depth