[Set 2]MCQ’s on Electrical Welding|Electrical Welding MCQ Questions and Answers|KSEB Sub Engineer

Electrical Welding MCQ Questions and Answers

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[Set 1]MCQ’s on Electrical Welding|Electrical Welding MCQ Questions and Answers|KSEB Sub Engineer

Seam welding is normally not recommended for

(a) aluminum alloys.
(b) stainless and coated steels.
(c) copper and high copper alloys.
(d) alloys of nickel and magnesium.

Answer: (b) stainless and coated steels

In percussion welding

(a) the process used depends on the arc effect for heating and not on the resistance.
(b) the action of process is so rapid that there is little heating effect in the material adjacent to the weld.
(c) the equipment used is quite expensive.
(d) all of the above.

Answer: (d) all of the above

The basic electrical requirement in arc welding is that there should be

(a) high open-circuit voltage.
(b) no arc blow.
(c) dc power supply.
(d) coated electrodes.

Answer: (a) high open-circuit voltage

In arc welding, the temperature of the arc produced is of the order of

(a) 1,000°C
(b) 3,500 – 4,000°C
(c) 5,000 – 7,500°C
(d) 7,500 – 10,000°C

Answer: (b) 3,500 – 4,000°C

The electric arc has

(a) linear resistance characteristic.
(b) positive resistance characteristic.
(c) negative resistance characteristic.
(d) highly inductive characteristic.

Answer: (c) negative resistance characteristic

In electric arc welding, the voltage required to strike dc arc is about

(a) 50 – 60 V
(b) 80 – 90 V
(c) 100 – 120 V
(d) 220 V

Answer: (a) 50 – 60 V

In electric arc welding, the voltage required to strike an ac arc is about

(a) 50 – 60 V
(b) 80 – 90 V
(c) 100 – 120 V
(d) 230 V

Answer: (b) 80 – 90 V

In electric arc welding, the voltage required to maintain the arc will be

(a) 250 – 500 V
(b) 150 – 250 V
(c) 20 – 30 V
(d) below 10 V

Answer: (c) 20 – 30 V

For electric arc welding the current range is usually

(a) 50 – 1,000 A
(b) 30 – 50 A
(c) 20 – 30 A
(d) below 20 A

Answer: (a) 50 – 1,000 A

Increased heat due to a shorter arc is harmful owing to

(a) burn through.
(b) excessive porosity.
(c) undercutting of base material.
(d) all of the above.

Answer: (d) all of the above

Arc blow results in

(a) non-uniform weld beads.
(b) shallow weld puddle giving rise to weak weld.
(c) splashing out of metal from weld puddle.
(d) all of the above defects.

Answer: (d) all of the above defects

Arc blow effects occurring with dc welding machines can be reduced by

(a) shortening the arc column length.
(b) reducing the welding current or electrode size or rate of travel of the electrode.
(c) wrapping the welding electrode cable a few turns around the work.
(d) all of the above.

Answer: (d) all of the above

In electric welding, major personal hazards are

(a) weld spatter.
(b) flying sparks.
(c) harmful infrared and ultraviolet rays from the arc.
(d) all of the above.

Answer: (d) all of the above

During electric arc welding as the thickness of the metal to be welded increases

(a) voltage is increased keeping current the same.
(b) current is increased keeping voltage unchanged.
(c) current and voltage, both are increased.
(d) current and voltage, both are reduced.

Answer: (b) current is increased keeping voltage unchanged

In a dc arc welding

(a) both electrode as well as workpiece are made +ve
(b) both electode as well as workpiece arc made -ve.
(c) electrode is made -ve and workpiece +ve.
(d) electrode is made +ve and workpiece -ve.

Answer: (c) electrode is made -ve and workpiece +ve

The length of arc required depends on

(a) kind of electrodes used, its coating and its diameter.
(b) magnitude of current used.
(c) position of welding.
(d) all of the above.

Answer: (d) all of the above

The overhead welding position is thought to be the most

(a) hazardous.
(b) economical.
(c) useful.
(d) difficult.

Answer: (a) hazardous

In arc welding best results are obtained when arc length is equal to

(a) 25 mm.
(b) 19 mm.
(c) diameter of electrode.
(d) double the diameter of the electrode.

Answer: (c) diameter of electrode

Flat-position welding is considered to be the most

(a) easiest and most economical.
(b) hazardous.
(c) adaptable for welding of both ferrous and non-ferrous metals particularly for cast iron.
(d) both (a) and (c).

Answer: (d) both (a) and (c)

In direct current straight polarity (DCSP) or electrode negative welding

(a) heavily coated electrodes are used.
(b) base metal penetration is narrow and deep.
(c) electrode is the hottest.
(d) workpiece is relatively cooler.

Answer: (b) base metal penetration is narrow and deep

In direct current reverse polarity or electrode positive welding

(a) workpiece is the hottest.
(b) bare and medium coated electrodes can be used.
(c) electrode is the hottest.
(d) base metal penetration is narrow and deep.

Answer: (c) electrode is the hottest

The electrode is coated in order to

(a) improve bead quality.
(b) cleanse the base metal.
(c) provide shielding to weld pool.
(d) prevent atmospheric contamination.

Answer: (a) improve bead quality

In DCRP or electrode-positive welding, the heat produced at the electrode is………of total heat produced.

(a) one-third.
(b) two-third.
(c) three-fourth.
(d) one-fourth.

Answer: (b) two-third

A 10 SWG electrode usually operates in the current range of

(a) 95 – 135 A
(b) 80 – 95 A
(c) 45 – 70 A
(d) 20 – 30 A

Answer: (a) 95 – 135 A

Electrode of 8 SWG is to be employed for welding two 12.5 mm steel plates. The current required will of the order of

(a) 20 A
(b) 50 A
(c) 150 A
(d) 250 A

Answer: (c) 150 A

The purpose of coating on arc welding electrodes is to

(a) provide a protective covering.
(b) provide slag for protection of the molten metal.
(c) stabilize the arc.
(d) all of the above.

Answer: (d) all of the above

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