EASY PSC | Junior Instructor (Welder) - Industrial Training Answer Key

Question 1

The stub end of an electrode should normally be not more than

A

5% of electrode

B

10% of electrode

C

15% of electrode

D

20% of electrode

Question 2

There are three pre-requisites for any fire or explosion to take place. Which one of the following is not included in the three pre-requisites ?

A

Fuel

B

Nitrogen

C

Oxygen

D

Ignition

Question 3

In welding procedure, the PQR is stands for

A

Parent Quantity Record

B

Present Quality Reading

C

Procedure Qualified Record

D

Procedure Qualification Record

Question 4

Material difficult to be spot welded is

A

Copper

B

Mild steel

C

Carbon steel

D

Stainless steel

Question 5

What is the name of fusion zone in spot welding ?

A

Toe

B

Crater

C

Nugget

D

Shoulder

Question 6

In which process cutting is possible in all positions on location ?

A

Metal arc cutting

B

Carbon arc cutting

C

Plasma arc cutting

D

Oxygen acetylene cutting

Question 7

The velocity of plasma arc cutting stream is

A

500 m/sec.

B

600 m/sec.

C

700 m/sec.

D

800 m/sec.

Question 8

In plasma arc welding, the working temperature is

A

10000°C – 15000°C

B

20000°C – 30000°C

C

35000°C – 40000°C

D

40000°C – 45000°C

Question 9

Electron beam welding, the tungsten filament unit, electrons is heated in vacuum chamber at

A

1000°C

B

2000°C

C

3000°C

D

4000°C

Question 10

Laser beam welding is used in

A

Aircraft

B

Ships

C

Railways

D

Body building

Question 11

Which welding process is more suitable for joining dissimilar metals ?

A

GMAW

B

GTAW

C

Friction welding

D

Submerged arc welding

Question 12

Which gas is used for TIG welding of aluminium ?

A

CO2

B

Argon

C

Oxygen

D

Nitrogen

Question 13

Which welding is generally recommended for pipe to pipe or tube to tube joint ?

A

GTAW/Gas

B

GTAW/Arc

C

GTAW/CO2

D

GTAW/TIG

Question 14

Which gas have greater arc stability than with helium ?

A

CO2

B

Argon

C

Helium

D

Hydrogen

Question 15

In GTAW, the tungsten electrode fusion approximately at

A

1500°C

B

2230°C

C

3380°C

D

4500°C

Question 16

In GTAW process, tungsten with 2% thorium electrode is marked with

A

Red colour

B

Blue colour

C

Black colour

D

Green colour

Question 17

What is the purpose of high frequency unit in GTAW welding ?

A

To produce the arc

B

To cooling the torch

C

To cooling the nozzle

D

To initiate the arc without touching the electrode on the base metal

Question 18

In GTAW process, aluminium is welded by

A

Rectifier set

B

AC power source

C

DC power source

D

Engine driven set

Question 19

Nickel and titanium is only welded for

A

GTAW

B

FCAW

C

GMAW

D

MMAW

Question 20

What is the use of backing strips and backing bars while welding the product ?

A

To support the job

B

To strengthen the job

C

To minimize the defects

D

To minimize the distortion and contraction

Question 21

What is the thermit reaction time ?

A

4 – 6 seconds

B

7 – 10 seconds

C

14 – 20 seconds

D

25 – 30 seconds

Question 22

Thermit for welding electric connections consist of

A

Nitrogen and Steel

B

Helium and Copper

C

Hydrogen and Tungsten

D

Copper oxide and Aluminium

Question 23

In which part of the electro slag, unit is used to deliver the electrode wire through the guide tube to the molten flux ?

A

Wire feeder

B

Control panel

C

Electrode guide tube

D

Water cooled copper shoes

Question 24

The temperature of molten slag pool in electro slag welding is

A

1400°C

B

1650°C

C

1800°C

D

2100°C

Question 25

In which welding process, the thicker steel sections can be welded in a single pass in vertical position ?

A

SAW

B

SMAW

C

GMAW

D

Electro slag and electro gas welding

Question 26

In SAW process, use of run on and run off pieces for starting and ending is to avoid

A

Crack

B

Porosity

C

Undercut

D

Formation of crater

Question 27

What is the purpose of post-heating in certain welded jobs ?

A

To reduce the toughness

B

To increase the toughness

C

To reduce hardness and brittleness

D

To increase hardness and brittleness

Question 28

Pre-heating and post-heating is essential in welding of

A

Cast iron

B

German silver

C

Stainless steel

D

High speed steel

Question 29

Which kind of welding can be reduced the width of heat affected zone ?

A

SAW

B

Gas welding

C

Thermit welding

D

Atomic hydrogen welding

Question 30

If the weld metal melting completely through base metal, which resulting

A

Crack

B

Undercut

C

Burn through

D

Lack of fusion

Question 31

Which type of edge preparation is prepared to do for 25 mm plate in manual CO2 dip transfer ?

A

Single ‘u’

B

Double ‘j’

C

Double ‘v’

D

Double ‘u’

Question 32

In FCAW, what is the percentage of metal deposition of efficiency ?

A

60% – 65%

B

70% – 75%

C

80% – 86%

D

90% – 98%

Question 33

In GTAW process, the torch nozzle is made of

A

Lead

B

Copper

C

Ceramic

D

Aluminium

Question 34

State the purpose of using a gas heater.

A

To increase the gas velocity

B

To remove impurities from CO2 gas

C

To improve inert property of CO2 gas

D

Prevent freezing of moisture present in the regulator

Question 35

Which one of the following statement is correct in the selection of the wire electrode ?

A

Joint position of weld metal

B

Physical properties of weld metal

C

Chemical properties of weld metal

D

Mechanical properties of weld metal

Question 36

GMAW process 0.8 mm dia. electrode is mild steel welding spray arc transfer the current and voltage range is

A

80 – 100 Amps, 16 – 22 V

B

100 – 225 Amp, 17 – 22 V

C

150 – 265 Amps, 24 – 28 V

D

275 – 500 Amps, 24 – 32 V

Question 37

Which of the following is the only GMAW process parameter ?

A

Long arc

B

Stick out

C

Short arc

D

Damp electrode

Question 38

In GMAW process, the dip transfer voltage is

A

10 – 15 V

B

16 – 22 V

C

23 – 22 V

D

28 – 30 V

Question 39

In wire speed controls, the recommended range of wire speed is

A

1 – 25 m/min

B

1 – 30 m/min

C

1 – 35 m/min

D

1 – 40 m/min

Question 40

Which kind of process is more economical and less edge preparation ?

A

GMAW

B

SMAW

C

GTAW

D

SAW

Question 41

In GMAW process, volts ampere curve and constant current type ampere drop percentage is

A

10%

B

8.0%

C

6.7%

D

12.5%

Question 42

At what percentage of oxygen can cause dizziness, unconsciousness or even death ?

A

21%

B

23%

C

Less than 18%

D

More than 21%

Question 43

Mig welding of galvanized metal is extremely dangerous because it evaporate

A

Tin oxide

B

Zinc oxide

C

Lead oxide

D

Carbon monoxide

Question 44

In a nick break test, a saw cut depth is

A

2 – 2.5 mm

B

1.5 – 2 mm

C

1 – 1.4 mm

D

2.5 – 3 mm

Question 45

Which one of the test is used to defect surface and sub-surface ?

A

Visual inspection

B

Radiographic test

C

Liquid penetrant test

D

Magnetic particle test

Question 46

Which one is to check the contour of welds ?

A

Scale

B

Template

C

Slip gauge

D

Vernier calipers

Question 47

Name the tool which will avoid the damage and impression on the metal sheets.

A

Ball peen hammer

B

Cross peen hammer

C

Straight peen hammer

D

Mallet

Question 48

Which shade number of the filter glass is fitted in the helmet for MMAW ?

A

Shade number – 6

B

Shade number – 8

C

Shade number – 10

D

Shade number – 12

Question 49

Which one of the following welding machine will supply alternating curved for welding ?

A

Rectifier set

B

Transformer set

C

Engine driver generator set

D

Motor generator set

Question 50

Open circuit voltage of welding machine is

A

18 – 40 V

B

40 – 95 V

C

60 – 110 V

D

130 – 170 V

Question 51

The unit of electric resistance is called as

A

Volt

B

Ohms

C

Joule

D

Ampere

Question 52

Weld metal deposited above the surface of the parent metal is called

A

Weld zone

B

Sealing run

C

Packing run

D

Reinforcement

Question 53

Which kind of angle used to prepare the single bevel in M.S. material for welding purpose ?

A

25°

B

35°

C

45°

D

60°

Question 54

Ratio of oxygen to acetylene for complete combustion is

A

1 : 1

B

2 : 1

C

1.5 : 1

D

2.5 : 1

Question 55

The pressure of acetylene gas for gas cutting a 10 mm M.S. plate is

A

0.6 kgf/cm^2

B

0.15 kgf/cm^2

C

1.0 kgf/cm^2

D

1.5 kgf/cm^2

Question 56

Identify the welding machine which is used to avoid arc blow.

A

Rectifier

B

Generator

C

Transformer

D

Engine driven set

Question 57

The angle formed between the line of the weld root and the horizontal reference plate is

A

Weld slope

B

Face of weld

C

Weld rotation

D

Welding position

Question 58

The imaginary line passing through the weld centre lengthwise is known as

A

Weld slope

B

Axis of weld

C

Face of weld

D

Weld rotation

Question 59

Welding position is determined by

A

Slope and rotation

B

Axis and face of weld

C

Face of weld and slope

D

Axis of weld and rotation

Question 60

Name the defect, the micro structure properties affected by welding heat.

A

Crater

B

Porosity

C

Toe crack

D

Heat affected zone

Question 61

Changing the direction of current flow in DC welding machine is

A

Voltage

B

Polarity

C

Ampere

D

Frequency

Question 62

The percentage of calcium and carbon in calcium carbide is

A

60 : 40

B

70 : 30

C

62.5 : 37.5

D

69.7 : 30.3

Question 63

What is the post-heating temperature for welding medium carbon steel plate ?

A

90°C to 100°C

B

300°C to 600°C

C

100°C to 300°C

D

600°C to 900°C

Question 64

The percentage of carbon in acetylene gas is

A

80.3%

B

85.2%

C

89.5%

D

92.3%

Question 65

Which type of valve is used in flashback arrestor ?

A

Needle valve

B

Globe valve

C

Non return valve

D

Pressure control valve

Question 66

In which temperature liquid oxygen becomes solid ?

A

– 200°C

B

– 210°C

C

– 218.4°C

D

– 225.4°C

Question 67

One kilogram of liquid oxygen produces

A

750 litre of oxygen gas

B

800 litre of oxygen gas

C

850 litre of oxygen gas

D

900 litre of oxygen gas

Question 68

What is capacity of acetylene cylinder ?

A

3.5 m^3 – 8.5 m^3

B

4.5 m^3 – 8.5 m^3

C

5.3 m^3 – 8.5 m^3

D

7.5 m^3 – 8.5 m^3

Question 69

Acetylene gas leakage is identified by

A

Soapy water

B

Fresh water

C

Hard water

D

Normal water

Question 70

For what purpose of placing of wedge or an alignment clamp between plates ahead of the weld ?

A

Improper welding

B

In complete penetration

C

Overlapping

D

Divergence allowance

Question 71

In rightward welding method of pipe ends bended in which angle can be done pipe butt joint ?

A

30° – 40°

B

50° – 70°

C

75° – 85°

D

85° – 90°

Question 72

Which cracks develop at the end of the weld joint ?

A

Toe crack

B

Under crack

C

Crater crack

D

Longitudinal crack

Question 73

If more than one cylinder is connected in a system is called

A

Series system

B

Multiple system

C

Manifold system

D

Group system

Question 74

Which types of pipe is used in DA manifold system ?

A

GI pipe

B

Steel pipe

C

Copper pipe

D

Aluminium pipe

Question 75

The suitable flux for welding of stainless steel is

A

Titanium chloride

B

Sodium borate

C

Magnesium chloride

D

Zinc chloride and potassium dichromate

Question 76

Which steps to be taken to avoid lack of fusion in gas welding ?

A

Weld with flow speed

B

Weld with uniform speed

C

Weld with decreased filler rod

D

Weld with increased filler rod angle

Question 77

What is the coating factor for medium coated electrode ?

A

1.25 to 3

B

1.4 to 1.5

C

1.6 to 2.2

D

2.3 to 2.5

Question 78

Which electrode is used to root pass welding of high pressure pipes ?

A

Rutile

B

Iron powder

C

Basic coated

D

Cellulosic

Question 79

In which substance coated electrode can be used AC/DC reverse polarity ?

A

Silicon

B

Copper

C

Titanium

D

Manganese

Question 80

Cast iron welded after performing the pre-heating range of temperature is

A

200°C – 210°C

B

180°C – 200°C

C

150°C – 180°C

D

250°C – 300°C

Question 81

In which polarity, low hydrogen electrode is used ?

A

AC straight

B

AC reverse

C

DC reverse

D

DC straight

Question 82

In 3 mm thickness of high carbon steel, which diameter of filler rod can be used ?

A

1.6 mm diameter

B

2.00 mm diameter

C

2.5 mm diameter

D

3 mm diameter

Question 83

Which alloying element increases hardness and toughness ?

A

Vanadium

B

Tungsten

C

Chromium

D

Manganese

Question 84

The major problem in welding stainless steel is

A

High electrical resistance

B

Poor electrical resistance

C

Poor thermal conduction

D

Formation of chromium carbide

Question 85

Which type of filler rod is to be selected to avoid weld decay in stainless steel welding ?

A

Columbium based

B

Phosphur bronze

C

Super silicon based

D

Copper coated mild steel

Question 86

Which flame is suitable for brass welding ?

A

Slightly neutral flame

B

Carburizing flame

C

Neutral flame

D

Oxidizing flame

Question 87

The divergence allowance for gas welding of 300 mm long copper butt joint is

A

1 to 2 mm

B

3 to 4 mm

C

4 to 5 mm

D

5 to 6 mm

Question 88

Which kind of welding process can be joint by dissimilar metals ?

A

Bronze welding of copper

B

Bronze welding of cast iron

C

Bronze welding of brass

D

Bronze welding of mild steel

Question 89

Melting point of aluminium oxide is

A

500°C

B

659°C

C

850°C

D

1930°C

Question 90

Which of the following nozzle size is selected for 3 mm thickness aluminium and its alloy ?

A

3

B

5

C

7

D

9

Question 91

Comparing to welding electrode, gouging electrode needs

A

5 – 10% current

B

10 – 20% higher current

C

10 – 30% lower current

D

20 – 50% higher current

Question 92

Which type of cast iron is very hard and brittle and is not weldable, and also not easily machinable ?

A

Nodular cast iron

B

Malleable cast iron

C

Gray cast iron

D

White cast iron

Question 93

The cast iron material has often post-heating which kind of cooling to be done ?

A

Oil

B

Air

C

Sand

D

Water

Question 94

Which is not true about calcium carbide ?

A

It is brittle

B

It absorbs moisture from atmosphere

C

It produces acetylene when brought in contact with water

D

It is soluble in kerosene oil

Question 95

In a gas cut plate, the cut shows grooves and has deep drag lines. This is due to

A

Tip too close to the cut surface

B

Too much travel speed

C

Less oxygen pressure

D

Smaller size cutting nozzle

Question 96

What percentage of chromium and nickel are usually present in stainless steel ?

A

15% Chromium, 5% Nickel

B

16% Chromium, 6% Nickel

C

17% Chromium, 7% Nickel

D

18% Chromium, 8% Nickel

Question 97

Which type of welding source is preferred for welding of non-ferrous metals ?

A

Welding transformer

B

Welding rectifier

C

Motor-generator set

D

Capacitor set

Question 98

In resistance welding, if the current is doubled, the heating effect becomes

A

Double

B

Four times

C

Eight times

D

Sixteen times

Question 99

The presence of oxygen can reduce

A

Strength

B

Ductility

C

Malleability

D

Toughness

Question 100

Which of the following elements is added to steel to increase its resistance to corrosion in environments like seawater ?

A

Aluminium

B

Copper

C

Titanium

D

Vanadium

070/2021 - Junior Instructor (Welder) - Industrial Training