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
Correct Answer :
C. Changing the electrode size
Related Questions
The structure of a grinding wheel depends upon
Hardness of the material being ground
Nature of the grinding operation
Finish required
All of these
The grinding wheel speed (surface speed in m/min) usually varies from
500 to 1000
1000 to 1500
1500 to 2000
2000 to 2500
The type of tool used on milling machine and broaching machine is
Single point cutting tool
Two point cutting tool
Three point cutting tool
Multipoint cutting tool
The cutting fluid mostly used for machining steel is
Water
Soluble oil
Dry
Heavy oils
In up-cut milling the work piece is fed
Against the rotating cutter
At angle of 60° to the cutter
In the direction of the cutter
At the right angle to the cutter
What is the name of the device used in arc welding circuits for the purpose of modifying the rate of current change when the weld road is varied rapidly?
Reactor
Kerf
Inductor
Cone
Match the following metal forming processes with their associated stresses in the work piece.
| Metal forming process | Types of stress |
|---|---|
| 1. Coining | P. Tensile |
| 2. Wire Drawing | Q. Shear |
| 3. Blanking | R. Tensile and compressive |
| 4. Deep Drawing | S. Compressive |
1-S, 2-P, 3-Q, 4-R
1-S, 2-P, 3-R, 4-Q
1-P, 2-Q, 3-S, 4-R
1-P, 2-R, 3-Q, 4-S
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
In electrochemical machining, the gap between the tool and work is kept as
0.1 mm
0.4 mm
0.35
0.75 mm
The tool material, for faster machining, should have
Wear resistance
Red hardness
Toughness
All of these
The helix angle of a drill is __________ for drilling brass.
Equal to 30°
Less than 30°
More than 30°
None of these
It is required to cut screw threads of 2 mm pitch on a lathe. The lead screw has a pitch of 6 mm. If the spindle speed is 60 r.p.m., then the speed of lead screw will be
10 r.p.m.
20 r.p.m.
120 r.p.m.
180 r.p.m.
The size of a lathe is specified by the
Length between centres
Swing diameter over the bed
Swing diameter over the carriage
All of these
Which of the following statement is correct for orthogonal cutting system?
The cutting edge of the tool is perpendicular to the direction of tool travel.
The cutting edge clears the width of the workpiece on either ends.
The chip flows over the tool face and the direction of the chip flow velocity is normal to the cutting edge.
All of the above
The maximum possible draft in cold rolling of sheet increases with the
Increase in coefficient of friction
Decrease in coefficient of friction
Decrease in roll radius
Decrease in roll velocity
An open structure of a grinding wheel is used for
Soft materials
Tough materials
Ductile materials
All of these
The example of snag grinding is
Trimming the surface left by sprues and risers on castings
Grinding the parting line left on castings
Removing flash on forgings
All of these
In which of the following machine, the work rotates and the tool is stationary?
Vertical boring machine
Horizontal boring machine
Precision boring machine
Jig boring machine
The effective number of lattice points in the unit cell of simple cubic, body centred cubic, and face centred cubic space lattices, respectively, are
1, 2, 2
1, 2, 4
2, 3, 4
2, 4, 4
Crater wear is predominant in
Carbon tool steels
Tungsten carbide tools
High speed steel tools
Ceramic tools
In a shaper
Tool is stationary and work reciprocates
Work is stationary and tool reciprocates
Tool moves over stationary work
Tool moves over reciprocating work
Fixtures are used
For holding and guiding the tool in drilling, reaming or tapping operations
For holding the work in milling, grinding, planing or turning operations
To check the accuracy of workpiece
None of the above
For turning internal tapers, the suitable method is
By a form tool
By setting over the tail stock
By a taper turning attachment
By swivelling the compound rest
The type of reamer used for reaming soft aluminium or copper, is
Straight fluted reamer
Left hand spiral fluted reamer
Right hand spiral fluted reamer
Any one of these
In a single point turning operation with a cemented carbide and steel combination having a Taylor exponent of 0.25, if the cutting speed is halved, then tool life will become
Half
Two times
Eight times
Sixteen times
The stroke of a shaping machine is 250 mm. It makes 30 double strokes per minute. The overall average speed of operation is
3.75 m/min
5 m/min
7.5 m/min
15 m/min
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
The facing is an operation of
Bevelling the extreme end of a workpiece
Embossing a diamond shaped pattern on the surface of a workpiece
Reducing the diameter of a workpiece over a very narrow surface
Machining the ends of a workpiece to produce a flat surface square with the axis
Which of the following statement is wrong?
The larger side rake angle produces chipping.
The smaller rake angle produces excessive wear and deformation in tool.
The side cutting edge angle (less than 15°) increases tool life.
The increase in nose radius decreases tool life.
Continuous chips with built up edge are formed during machining of
Brittle metals
Ductile metals
Hard metals
Soft metals