Tool life is generally better when
Grain size of the metal is large
Grain size of the metal is small
Hard constituents are present in the microstructure of the tool material
None of the above
Correct Answer :
A. Grain size of the metal is large
Related Questions
High speed steel drills can be operated at about _________ the speed of high carbon steel drills.
One-half
One-fourth
Double
Four times
Gear lapping is an operation
After heat treatment
Prior to heat treatment
For gear reconditioning
None of these
The velocity of tool along the tool face is known as
Shear velocity
Chip velocity
Cutting velocity
Mean velocity
High speed steel tools retain their hardness upto a temperature of
250°C
350°C
500°C
900°C
If the tearing efficiency of a riveted joint is 50%, then ratio of rivet hole diameter to the pitch of rivets is
0.20
0.30
0.50
0.60
Two plates of the same metal having equal thickness are to be butt welded with electric arc. When the plate thickness changes, welding is achieved by
Adjusting the current
Adjusting the duration of current
Changing the electrode size
Changing the electrode coating
Small nose radius
Increases tool life
Decreases tool life
Produces chipping and decreases tool life
Results in excessive stress concentration and greater heat generation
In centreless grinding, work place centre will be
Above the line joining the two wheel centres
Below the line joining the two wheel centres
On the line joining the two wheel centres
At the intersection of the line joining the wheel centres with the work place plane
In a metal arc welding process, a gas metal arc welding with magnetized flux is used and can be done in all the positions i.e. flat position, vertical position or inclined position.
Globular transfer
Spray transfer
GMAW practice
Dip transfer
During the execution of a CNC part program block NO20 GO2 X45.0 Y25.0 R5.0 ; the type of tool motion will be
Circular Interpolation − clockwise
Circular Interpolation − counter clockwise
Linear Interpolation
Rapid feed
Threading is an operation of
Smoothing and squaring the surface around a hole
Sizing and finishing a small diameter hole
Producing a hole by removing metal along the circumference of a hollow cutting tool
Cutting helical grooves on the external cylindrical surface
Crater wear leads to
Increase in cutting temperature
Weakening of tool
Friction and cutting forces
All of these
The cutting speed is maximum while machining __________ with a high speed steel tool.
Cast iron
Mild steel
Brass
Aluminium
Thread grinding requires work speed from
1 to 3 m/min
5 to 10 m/min
10 to 14 m/min
14 to 20 m/min
The actual feed in centerless grinders is given by (where d = Dia. of regulating wheel, n = Revolutions per minute, and α = Angle of inclination of wheel)
πd
πdn
πdn sinα
πdn cosα
As tool and work are not in contact in EDM process
No relative motion occurs between them
No wear of tool occurs
No power is consumed during metal cutting
No force between tool and work occurs
Hardness of steel greatly improves with
Annealing
Cyaniding
Normalizing
Tempering
The tail stock set over method of taper turning is preferred for
Internal tapers
Small tapers
Long slender tapers
Steep tapers
Which of the following statement is correct about hot machining?
It requires less power than machining metals at room temperature.
The rate of tool wear is lower.
It is used for machining high strength and high temperature resistant materials.
All of the above
The size of abrasive grain required in a grinding wheel depends upon the
Amount of material to be removed
Hardness of material being ground
Finish desired
All of these
In Oxyacetylene gas welding, temperature at the inner cone of the flame is around
3500⁰C
3200⁰C
2900⁰C
2550⁰C
In a planer
Tool is stationary and work reciprocates
Work is stationary and tool reciprocates
Tool moves over stationary work
Tool moves over reciprocating work
In order to obtain a surface finish in the range of 0.75 μm to 1.25 μm , the operation used is called.
Grinding
Lapping
Honing
Buffing
For softer materials, the point angle of the drill is kept
Equal to 118°
Less than 118°
More than 118°
Any one of these
In machining metals, surface roughness is due to
Feed marks or ridges left by the cutting tool
Fragment of built-up edge on the machined surface
Cutting tool vibrations
All of these
In metal cutting, use of low feeds and high cutting speeds is desired when the objective is
High metal removal rate
Dry machining
Use of soft cutting tool
Surface finish
The parameter which completely defines the chip formation in a metal cutting process is
Shear angle
Chip-tool contact length
Both (A) and (B)
None of these
The capacity of a material to be welded under the imposed fabrication conditions into a specific, suitably designed structure and to perform satisfactorily in the intended service is known as?
Weldment
Weld tab
Weldability
Tack weld
The enlarging of an existing circular hole with a rotating single point tool is called
Boring
Drilling
Reaming
Internal turning
In centreless grinders, the regulating wheel is inclined at
0° to 8°
9° to 15°
16° to 20°
21° to 25°