In arc welding, the electric arc is produced between the work and the electrode by
Voltage
Flow of current
Contact resistance
All of these
Correct Answer :
C. Contact resistance
Related Questions
Most of the oxyacetylene welding is done with
Neutral flame
Oxidising flame
Carburising flame
All of these
The metal is subjected to mechanical working for
Refining grain size
Reducing original block into desired shape
Controlling the direction of flow lines
All of these
The temperature produced by oxy-hydrogen flame is about
1800°C
2100°C
2400°C
3200°C
Green sand is a mixture of
30% sand and 70% clay
50% sand and 50% clay
70% sand and 30% clay
90% sand and 10% clay
The punch and die set up is ________ for punching and piercing operation.
Same
Similar
Different
None of these
A mortise gauge is a
Striking tool
Planing tool
Boring tool
Marking tool
The minimum size of a bloom is
5 cm × 5 cm
10 cm × 10 cm
15 cm × 15 cm
20 cm × 20 cm
In average work, the tolerance produced by investment casting method is
±0.05 mm
+0.2 mm
+05 mm
+1 mm
A jolt machine is used to
Ram the sand harder at the pattern face with decreasing hardness towards the back of the mould
Ram the sand harder at the back of the mould and softer on the pattern face
Produce uniform sand hardness throughout the mould
Produce uniform packing of sand in the mould
The operation of cutting a sheet of metal in a straight line along the length, is known as
Plunging
Notching
Slitting
Forming
In a _________, the molten metal is poured and allowed to solidify while the mould is revolving.
Die casting method
Slush casting method
Permanent mould casting method
Centrifugal casting method
A casting defect which occurs near the ingates as rough lumps on the surface of a casting is known as
Shift
Sand wash
Swell
Scab
Carburising flame is used to weld
Steel, cast iron, copper, aluminium etc
Brass and bronze
Hard surfacing materials such as stellite
All of these
During cold working process
Grain structure is distorted
Strength and hardness of metal increases
Close dimensional tolerance can be maintained
All of the above
A rip saw
Is a two man saw
Is used for cutting along the grains of wood
Has a narrow blade with two wooden handles
All of the above
Acetylene gas is stored in cylinders in
Solid form
Gaseous form
Liquid form
Any one of these
The recrystallisation temperature of steel is
400°C
600°C
800°C
None of these
In a hot chamber die casting machine
Melting pot is separate from the machine
Melting pot is an integral part of the machine
Melting pot may have any location
High temperature and pressure is used
The flux commonly used in brazing is
Zinc chloride
Ammonium chloride
Rosin plus alcohol
Borax
In order to ram the sand harder at the back of the mould and softer on the pattern face, a ________ is used.
Sand slinger
Squeezing machine
Jolt machine
Stripper plate machine
In forehand welding, the angle between the welding rod and the work is kept as
30°-40°
40°-50°
50°-60°
60°-70°
The increase in hardness due to cold working, is called
Age hardening
Work hardening
Induction hardening
Flame hardening
The machining allowance provided on patterns depends upon
Type of casting metal
Size and shape of casting
Method of casting used
All of these
The operation of cutting a cylindrical hole in a sheet of metal by the punch and die is called
Shearing
Piercing
Punching
Blanking
In a simple die
Two or more operations are performed simultaneously at the single stroke of the ram
Two or more cutting operations are performed at one station of the press in every stroke of the ram
Both cutting and non-cutting operations are performed at one station of the press in every stroke of the ram
None of the above
The upsetting is a process of
Increasing the cross-section of a bar
Reducing the cross-section of a bar
Joining the two surfaces of metal under pressure after heating
Bending of a bar
The maximum flame temperature occurs
At the outer cone
At the inner cone
Between the outer and inner cone
At the torch tip
The operation of cutting of a flat sheet to the desired shape is called
Shearing
Piercing
Punching
Blanking
Which of the following statement is wrong?
The angular clearance on dies varies from 0.5° to 1°
In drawing operation, the metal flows due to plasticity
In press operation, the size of the pierced hole is independent of the size of punch
None of the above
The edge of a steel plate cut by oxygen cutting will get hardened when the carbon content is
Less than 0.1 percent
Less than 0.3 percent
More than 0.3 percent
Anywhere between 0.1 to 1 percent