Welding

Question 1

What are the 3 harmful rays from cutting?

Answer 1

Visible light rays
Ultraviolet light rays
Infrared light rays

Question 2

What is the best protective clothing for welding?

Answer 2

Leather is best
Wool
Denim
Cotton

Question 3

What is the most suitable lens for heating and cutting?

Answer 3

4-5 green lens

Question 4

What three elements are used in the fire triangle?

Answer 4

Heat, fuel, oxygen

Question 5

What are the 4 classes of fire

Answer 5

A-wood and paper
B-flammable liquids
C-electrical
D-combustible metals

Question 6

How long does spark watch need to stay after hot work is complete?

Answer 6

30min

Question 7

When cutting galvanized what is needed?

Answer 7

Approved air line respirator

Question 8

What is the percentage of oxygen used for cutting?

Answer 8

99.5 percent

Question 9

What happens when you introduce grease to oxygen?

Answer 9

Explosion or fire

Question 10

A new oxygen cylinder is fully charged to what PSI?

Answer 10

2200 psi

Question 11

Mark all empty bottles with what symbol?

Answer 11

M/T

Question 12

What thread is oxygen components?

Answer 12

Right hand thread

Question 13

How much is the oxygen cylinder opened when in use?

Answer 13

All the way

Question 14

What and where is the rupture disc on the oxygen cylinder?

Answer 14

Disc mounted on the rear of the cylinder valve and is a safety to blow off at 3200 psi. This will slowly release oxygen instead of exploding.

Question 15

What are the physical properties of oxygen?

Answer 15

Colourless, odorless and tasteless

Question 16

What are the properties of acetylene

Answer 16

Colourless, strong pungent odour

Question 17

What is the critical point of acetylene at 70 F/21C

Answer 17

28 psi

Question 18

What is max safe working pressure for acetylene?

Answer 18

15psi

Question 19

What is in acetylene bottles to absorb acetylene ?

Answer 19

40 percent acetone

Question 20

What is draw limit of an acetylene bottle?

Answer 20

The maximum amount of acetylene that can be drawn before acetone is drawn out.

Question 21

What is a fusible plug?

Answer 21

Safety valve when dangerous temperatures are present. The melting temp is 212f/100C

Question 22

Where are the fusible plug located?

Answer 22

Bottom of cylinder, collar or neck ring and shoulder of the cylinder

Question 23

What hand thread are the acetylene opponents?

Answer 23

Left hand

Question 24

What are the hose colours?

Answer 24

Acetylene is red

Oxygen is green

Question 25

How much do you open acetylene bottle?

Answer 25

1 1/2 to 2 turns for knob 1 - 1 1/2 for key type

Question 26

What are regulators for?

Answer 26

Reduce cylinder pressure to a usable working pressure.

Question 27

What do flash back arrestors do?

Answer 27

Prevent flames from travelling back to the bottle

Question 28

What are the uses of a rosebud?

Answer 28

Bending, straightening, preheating, shrink fitting, hardsurfacing large areas.

Question 29

What oxygen pressure and acetylene pressure for rosebud?

Answer 29

Equal pressure. Number of holes in tip = PSI

Question 30

What is a backfire? What is the cause?

Answer 30

The flame backs up into the tip. Often caused by unequal pressure and to little gas flow.

Question 31

What is a flash back? What causes it?

Answer 31

One of the gases backs up into the other line forming an explosive mixture. The cause is grossly unequal pressure, faulty seats, or faulty manipulation of valves.

Question 32

What is burn back? What causes it?

Answer 32

Combustion takes place in the tip and mixer. Black smoke, red sparks and screeching sound emit from the tip. Hot tip Tip orifices enlarged Faulty mixer or torch body seats

Question 33

What metals are suitable for torch cutting?

Answer 33

Typically ferrous metals, with exceptions

Question 34

What materials are not suitable for cutting?

Answer 34

Non ferrous metals such as copper, brass, bronze, aluminum and their alloys.

Question 35

When cutting a beveled edge where do you line up you preheat holes?

Answer 35

Equally divided on either side of the cut line.

Question 36

When cutting a straight line where do the pre heat holes line up?

Answer 36

The lead hole is inline with the cut line.

Question 37

What are the two different hole cutting methods?

Answer 37

Travelling torch method - quicker method Still torch method - best for small diameter holes.

Question 38

What are the 3 types of flame?

Answer 38

Carbonizing - adds carbon to weld Neutral - adds nothing to weld deposit Oxidizing - attacks the carbon

Question 39

What is brazing suitable for?

Answer 39

Joining smaller assemblies and complex shapes, where different kinds of metals need to be joined.

Question 40

What are typical filler rods made of?

Answer 40

Alloys

Question 41

How can you tell when brazing temperature is reached?

Answer 41

Flux is clear, active and looks watery and the metal surface is visible underneath.

Question 42

Liquid propane expands to what?

Answer 42

270 times the volume.