CWB 2 All Module Exams QUESTIONS & ANSWERS(RATED A+)

CWB 2 All Module Exams QUESTIONS
& ANSWERS(RATED A+)
A Plasma is:

A) A gas made up of positive ions and free electrons
B) A liquid used to reduce adherence of spatter
C) The main component in an inverter power source
D) Always present in an electrical circuit - ANSWERA) A gas made up of positive
ions and free electrons

To increase melting rate (burn-off rate) in the shielded metal arc welding (SMAW)
process, which polarity should be used?
A) DCEP
B) ACEP
C) DCEN
D) ACEP - ANSWERC) DCEN

A self-regulating welding arc is produced by a:

A) Constant current power source with a constant speed wire feed system
B) Constant voltage power source with a voltage sensing wire feed system
C) Constant current power source
D) Constant voltage power source with a constant speed wire feed system -
ANSWERD) Constant voltage power source with a constant speed wire feed system

Short circuit current is determined by the:

A) Voltage in the circuit
B) Static characteristic of the power source
C) Position of welding
D) Skill of the welder - ANSWERB) Static characteristic of the power source

A Transformer is a device that:

A) Transforms AC to DC
B) Works only to change a DC voltage
C) Changes the value of an AC voltage but does not change the frequency
D) Is made from a semiconductor - ANSWERC) Changes the value of an AC voltage
but does not change the frequency

Which type of welding power source is used for the SMAW process?

A) Constant Current
B) Constant Voltage
C) Pulsed Current
D) Pulsed Voltage - ANSWERA) Constant Current

,The purpose of a drooping welding power source is to produce:

A) Constant voltage regardless of the current demand
B) Constant arc length regardless of current
C) Nearly constant current regardless of voltage fluctuations
B) Low open circuit voltage - ANSWERC) Nearly constant current regardless of
voltage fluctuations

A Rectifier is a device that converts:

A) DC current to AC current
B) AC Current to a high value DC current
C) DC current to a high value DC current
D) AC current to DC current - ANSWERD) AC current to DC current

Microprocessor controls are used in the more modern welding power sources to:

A) Provide more sophisticated levels of control for the welding system
B) Allow welding variables to be stored for use later
C) Provide feedback control
D) All of the above - ANSWERD) All of the above

Inverter welding power sources provide increased control over the welding arc
because they:

A) Utilize feedback control
B) Can respond very quickly to correct any changed in the welding circuits
C) Can utilize advanced pulsed waveforms to allow out of position welding using
spray transfer
D) All of the above - ANSWERD) All of the above

It would be correct to say:

A) Expansion and contraction are proportional to the dimensions of the heated area
B) When a bar is heated under restraint, its stress relieves itself as it cools
C) Slow cooling of a heated area will provide the greatest amount of shrinkage
D) When metal is heated it expands, but it does not shrink back to its original size
when it cools - ANSWERA) Expansion and contraction are proportional to the
dimensions of the heated area

To reduce the amount of angular distortion you should:

A) Increase the travel speed
B) Reduce the angle of preparation
C) Pre-heat the metal
D) All of the above
E) None of the above - ANSWERD) All of the above

When a structural member has been bent sharply, it can be straightened by heating:

, A) A vee shaped section of the web underneath the bent area of the flange
B) The inside corner of an angle, channel, i-beam, or T bar
C) A vee shaped area at the point of the greatest bend, with the top of the vee at the
point of greatest bend
D) All along the edge of the section
E) All along the edge opposite of the one which is bent - ANSWERC) A vee shaped
area at the point of the greatest bend, with the top of the vee at the point of greatest
bend

Of the many mechanical means of controlling distortion, the following will have the
least residual stress:

A) Rigid clamping
B) Subassembly of the sections
C) Heavy strongbacks, welded on both sides of the joint
D) Similar weldments clamped back to back
E) Pre-set the plates to allow recovery of angular distortion - ANSWERE) Pre-set the
plates to allow recovery of angular distortion

Decreasing the number of weld beads in a specific weld will:

A) Result in annealing the weld area
B) Give a finer grain structure
C) Reduce the transverse shrinkage
D) Increase the transverse shrinkage
E) Possibly crack the root pass - ANSWERC) Reduce the transverse shrinkage

The neutral axis is the:
A) Line on which there will be neither tension nor compression when the piece is
flexed or bent
B) Centreline of a weld bead halfway between the root pass and the face pass
C) Outside centreline of the web of a channel
D) Inside corner line of an unequal leg steel angle
E) Dimensional halfway point of a welded assembly - ANSWERA) Line on which
there will be neither tension nor compression when the piece is flexed or bent

When expansion and contraction are prevented, heating and cooling may cause:

A) No residual stresses
B) Failure due to lamellar tearing
C) No permanent deformation or failure
D) Failure when the metal is highly ductile
E) Failure when metal is not sufficiently ductile - ANSWERE) Failure when metal is
not sufficiently ductile

When heated, unrestrained metal will expand:

A) Transversely (across the weld)
B) Volumetrically (in all directions)