Deck 31: Oxyfuel Welding and Cutting Equipment, Setup, and Operation

Question 1

When mixing oxygen and fuel gas, one method uses a higher oxygen pressure and mixes gases in a(n) ____.

A) mixing chamber
B) injector chamber
C) fuel injector
D) injector mixer

Answer 1

B

Question 2

The pressure on a gauge is read as ____ gauge.

A) pounds per square inch
B) foot-pounds
C) kilograms per square inch
D) kilojoules

Answer 2

A

Question 3

There are ____ basic methods for mixing oxygen and fuel gas to form a hot, uniform flame.

A) two
B) three
C) four
D) five

Answer 3

A

Question 4

The ____ pressure gauge shows the pressure at the regulator.

A) working
B) cylinder
C) two-stage
D) constant

Question 5

The injector allows oxygen at the higher pressure to draw the fuel gas into the chamber even when the fuel gas pressure is as low as ____.

A) 6 psig
B) 6 oz/inch2
C) 10 psig
D) 10 oz/inch2

Question 6

The ____ gauge is used to indicate the amount of gas that remains in a cylinder.

A) working
B) cylinder
C) Bourdon
D) high-pressure

Question 7

The purpose of the ____ valve is to prevent gases from accidentally flowing through the torch and into the wrong hose.

A) flashback arrestor
B) reverse flow
C) safety release valve
D) safety disc

Question 8

Which of the following is true of a flashback?

A) It produces a low whistle.
B) When it occurs, the fuel valve should be closed first, followed by the oxygen valve.
C) A flame is burning back inside the tip, torch, hose, or regulator.
D) The valves should be closed slowly.

Question 9

In a two-stage regulator, the first spring ____.

A) is adjusted like other regulators
B) can be larger, allowing a greater flow
C) is preset at the factory to reduce pressure to 225 psig
D) has to control a maximum pressure of only around 225 psig

Question 10

____ seal tips must be tightened with a wrench.

A) O-ring
B) Gasket
C) Metal-to-metal
D) Rubber

Question 11

Gauges that do not read ____ when the pressure is released must be repaired or replaced.

A) 0 psig
B) 14 psig
C) 45 psig
D) 100 psig

Question 12

Which of the following is true of regulators?

A) All regulators work on different principles.
B) The regulator reduces the system pressure to the proper lower working pressure.
C) The lower pressure must be allowed to fluctuate over a range of flow rates.
D) All regulators can be safely interchanged for different pressure ranges.

Question 13

When mixing oxygen and fuel gas, one method uses equal or balanced pressure and mixes gases in a(n) ____.

A) mixing chamber
B) injector chamber
C) fuel injector
D) injector mixer

Question 14

Which of the following is a cause of a backfire?

A) The tip is not sufficiently hot.
B) The tip is too tight.
C) The flame settings are too high.
D) There is dirt in the tip.

Question 15

The ____ is designed to quickly stop the flow of gas during a flashback.

A) flashback arrestor
B) reverse flow valve
C) safety release valve
D) safety disc

Question 16

The size of a hose is the ____ of the hose.

A) inside circumference
B) outside circumference
C) inside diameter
D) outside diameter

Question 17

Hoses are available in four sizes: ____.

A) 3/16 in., 5/16 in., 3/8 in., 5/8 in.
B) 3/16 in., 1/4 in., 5/16 in., 3/8 in.
C) 1/4 in., 5/16 in., 3/8 in., 7/16 in.
D) 1/4 in.5/16 in., 3/8 in., 5/8 in.

Question 18

To obtain the absolute pressure, ____.

A) read the gauge pressure
B) add the atmospheric pressure to the gauge pressure
C) subtract the atmospheric pressure from the gauge pressure
D) multiply the atmospheric pressure by the gauge pressure

Question 19

When taping hoses together, the hoses should be wrapped for about ____ in.out of every ____ in.

A) one, five
B) two, ten
C) two, twelve
D) five, ten

Question 20

The torch pressure is always ____ the working pressure shown on the gauge.

A) less than
B) the same as
C) greater than
D) much greater than

Question 21

​Of the following fuel gases, which has the fastest burning velocity?

A) ​Acetylene
B) ​Natural gas
C) ​Propane
D) ​Hydrogen

Question 22

​The higher the combustion rate of an oxygen fuel mixture, the more prone the mixture is to ____.

A) ​burn-through
B) ​flashback
C) ​ignition
D) ​secondary combustion

Question 23

​The number of oxygen atoms required to completely combust the fuel gas ____.

A) ​is two
B) ​is four
C) ​varies, depending on its molecular makeup
D) ​varies, depending on its temperature

Question 24

​Of the following fuel gases, which has the slowest burn rate?

A) ​Acetylene
B) ​Natural gas
C) ​Propane
D) ​Hydrogen

Question 25

​Hydrocarbons are made up of ____.

A) ​hydrogen and carbon
B) ​oxygen and hydrogen
C) ​oxygen and carbon
D) ​oxygen, hydrogen, and carbon

Question 26

​A molecule of acetylene is made up of ____.

A) ​one acetone atom and one carbon atom
B) ​two oxygen atoms and two carbon atoms
C) ​one hydrogen atom and one carbon atom
D) ​two hydrogen atoms and two carbon atoms

Question 27

​The final products of all clean-burning hydrocarbon flames are ____.

A) ​oxygen and carbon
B) ​carbon dioxide and hydrogen
C) ​water vapor and oxygen
D) ​water vapor and carbon dioxide

Question 28

​Acetylene is unstable at pressures above ____ psig.

A) ​30
B) ​50
C) ​70
D) ​100

Question 29

​What is the finished flame product of reducing oxyhydrogen?

A) ​Carbon dioxide
B) ​Water
C) ​Carbon monoxide
D) ​Hydrogen peroxide

Question 30

Oxygen manifolds must be at least ____ feet away from fuel gas manifolds.

A) five
B) ten
C) fifteen
D) twenty

Question 31

​The withdrawal rate of gas from a cylinder should not exceed ____ of the total cylinder capacity per hour.

A) ​one-tenth
B) ​one-seventh
C) ​one-fifth
D) ​one-third

Question 32

​A molecule of propane is made up of ____.

A) ​one propyl and one carbon atom
B) ​one oxygen and one hydrogen atom
C) ​two hydrogen and two carbon atoms
D) ​eight hydrogen and three carbon atoms

Question 33

​Suppose the inner cone of a flame produces 430 Btu per cubic foot of gas, and the outer envelope produces 610 Btu per cubic foot of gas.What is the total heat produced by the flame?

A) ​520 Btu per cubic foot
B) ​1040 Btu per cubic foot
C) ​1220 Btu per cubic foot
D) ​262,300 Btu per cubic foot

Question 34

​Combining calcium carbide and water produces ____.

A) ​acetylene and calcium hydroxide
B) ​acetone and carbon monoxide
C) ​propane and calcium hydroxide
D) ​carbonated water and calcium hydroxide

Question 35

​Acetylene is produced by mixing ____.

A) ​acetyl alcohol and carbon
B) ​calcium carbide and water
C) ​carbon and water
D) ​acetyl alcohol and water

Question 36

​A homogeneous mixture of 50% acetylene and 50% oxygen has a burn rate of ____ feet per second.

A) ​2.7
B) ​12.7
C) ​22.7
D) ​32.7

Question 37

​Acetylene is unstable at temperatures above ____ Fahrenheit.

A) ​1435 $\degree$
B) ​1535 $\degree$
C) ​1635 $\degree$
D) ​1735 $\degree$

Question 38

​Acetone absorbs about ____ times its own weight in acetylene.

A) ​14
B) ​24
C) ​34
D) ​44

Question 39

​If more than one torch is to be used with a cylinder, the draw rates of the tips should be ____ to obtain the number of cylinders that must be manifolded together.

A) ​added
B) ​subtracted
C) ​multiplied
D) ​divided

Question 40

​The heat produced by the secondary flame of an MPS gas is about ____ the heat of acetylene.

A) ​half
B) ​the same as
C) ​twice
D) ​three times

Question 41

​In some cylinders a(n) ____________________ tube is used to improve the mixing of the gas by causing the liquid to be agitated as it is used.

Question 42

A(n) ____________________ will do the job of a reverse flow valve, and it will also stop the flame of a flashback.

Question 43

Most welding hoses used today are molded together as one piece and are referred to as ____________________ hose.

Question 44

A safety release valve is made up of a small ball held tightly against a(n) ____________________ by a spring.

Question 45

​____________________ gas is mostly methane and ethane.

Question 46

The ____________________ is a pressure difference caused by the resistance of a gas as it flows through a line.

Question 47

A safety ____________________ is a thin piece of metal held between two seals that prevents excessively high pressures from damaging the regulator.

Question 48

​____________________ produces only a primary combustion flame, unlike hydrocarbon gases, which have both primary and secondary combustion.

Question 49

​____________________ is used inside acetylene cylinders to absorb the gas and make it more stable.

Question 50

A(n) ____________________ torch must be used if a low-pressure acetylene generator or low-pressure residential natural gas is used as a fuel-gas supply.

Question 51

​What is the minimum tensile strength range of a class RG45 welding rod?

A) ​25,000 to 35,000 psi
B) ​35,000 to 45,000 psi
C) ​45,000 to 55,000 psi
D) ​55,000 to 65,000 psi

Question 52

​An infrared analysis or ____________________ of the flame gives the highest temperature in the flame.

Question 53

​The ____________________ or rate of propagation of a flame is the speed at which the flame burns.

Question 54

​Most fuel gases used for welding are ____________________.

Question 55

____________________ regulators have two sets of springs, diaphragms, and valves.

Question 56

The ____________________ inside the regulator gauge is bent in the shape of the letter C.

Question 57

​____________________ is produced by smelting coke (a coal by-product) and lime in air-tight electric arc furnaces.

Question 58

____________________ is rising pressure on the working side of the regulator.

Question 59

​What is the minimum tensile strength of a class RG65 welding rod?

A) ​35,000 to 45,000 psi
B) ​45,000 to 55,000 psi
C) ​55,000 to 65,000 psi
D) ​65,000 to 75,000 psi

Question 60

A regulator works by holding the forces on both sides of a(n) ____________________ in balance.

Question 61

​____________________ filler metals are welding rods that are mainly iron.

Question 62

How do you test a diaphragm for leaks?

Question 63

​What are the two major safety problems when hydrogen is used as a fuel gas?

Question 64

​The oxygen and ____________________ flame is the only 100% nonpolluting fuel-gas flame.

Question 65

What are the factors that affect the accuracy of fuel-gas flame temperature and heat readings?
​

Question 66

​Explain what happens, on the molecular level, in the primary and secondary combustion of acetylene.

Question 67

How does a regulator work?

Question 68

​Explain what happens on the molecular level when a mixture of acetylene and oxygen is ignited.

Question 69

What are the piping requirements for manifolds?

Question 70

What are the safety release devices on a regulator, and how do they work?

Question 71

What is backfire and what are its causes?

Question 72

​What are the properties of class RG65 welding rods?