Specialty Gas Metal Arc Welding

Question 1

What is the most common mode of metal transfer when welding base metal that is made of coated steel or stainless steel?

Answer 1

Short-circuit transfer

Question 2

What does GMAW stand for?

Answer 2

Gas Metal Arc Welding

Question 3

What GMAW process is used most for sheet metal work?

Answer 3

Short-circuit transfer

Question 4

What effect does changing the wire speed have on the voltage or amperage of the welding process?

Answer 4

The current varies with the amount of wire feed and increases in proportion to the wire speed.

Question 5

Which organizations have written specifications for GMAW filler metals?

Answer 5

AWS and CSA

Question 6

When using GMAW on mild steel with carbon dioxide shielding, which type of filler wire should be selected?

Answer 6

Deoxidized wire

Question 7

When wires are packaged in sealed containers, what are we protecting them from?

Answer 7

Moisture contamination

Question 8

Improperly stored wires most often produce welds with which defects?

Answer 8

Porosity

Question 9

When welding aluminum you ___ the gun towards the weld?

Answer 9

Push

Question 10

When welding stainless you ___ the gun towards the weld?

Answer 10

Pull

Question 11

Filler metals containing additional deoxidizers are intended for use on which metals?

Answer 11

Moderately rusty low-carbon steels

Question 12

When adding small percentages of oxygen to inert gases like argon, the oxidizing nature of oxygen breaks down surface tension on the molten metal and allows the puddle to?

Answer 12

Wet out the edges of the weld bead and minimize undercut in the molten weld.

Question 13

Which gas is the lightest?

Answer 13

Hydrogen

Question 14

Argon and helium are what kind of gases?

Answer 14

Inert gases

Question 15

Where would you use pure argon shielding gas with GMAW?

Answer 15

In the welding of non-ferrous metals such as aluminum, magnesium and their alloys.

Question 16

What is carbon dioxide gas primarily used for?

Answer 16

The welding of mild steel and low alloy steels

Question 17

What is a characteristic of helium used as a shielding gas when used with short-circuiting metal transfer?

Answer 17

A uniform penetration pattern and a broader weld bead result

Question 18

All GMAW processes need shielding gas. True or False?

Answer 18

False

Question 19

What is the recommended lens shade for a person welding aluminum or stainless steel?

Answer 19

They should use the darkest shade that is comfortable, but not lighter than the recommended one.

Question 20

What is the best material to wear while welding?

Answer 20

Heavy denim

Question 21

What is the best way to prevent sparks from entering your pockets and other entry’s?

Answer 21

Keep collars buttoned and pocket flaps and cuffs covered

Question 22

What must be done to cylinders being stored or transported?

Answer 22

They must have their protective caps in place, valves closed, and be stored in the upright position..

Question 23

What recommended pressure must remain in the depleted cylinder to avoid atmospheric contamination?

Answer 23

25 psi residual pressure

Question 24

What GMAW process is used mostly for welding lighter gauges of sheet metal work?

Answer 24

Short-circuit transfer

Question 25

What determines the type of metal transfer method?

Answer 25

The voltage used

Question 26

What is the recommended flow settings for shielding gas in cfh?

Answer 26

25 cfh

Question 27

What weld defect is not obvious, but very common to the GMAW process?

Answer 27

Cold lap

Question 28

What mixture is best to eliminate the spatter on mild steel?

Answer 28

Carbon dioxide and argon

Question 29

Which gas mixes tend to produce low crowned welds on stainless steels?

Answer 29

Argon - helium - carbon dioxide

Question 30

When 1 percent to 5 percent oxygen is added to argon shielding gas, it is to?

Answer 30

Improve wetting action

Question 31

Improperly stored stainless steel wire most often will produce welds with?

Answer 31

Porosity

Question 32

When you are welding austenitic stainless steels, why must you maintain the moisture content at low levels?

Answer 32

Because moisture can cause porosity

Question 33

What must you do because austenitic stainless steel has a very high coefficient of thermal expansion?

Answer 33

You must control distortion by balancing the heat input and minimize joint restraint.

Question 34

What does MIG stand for?

Answer 34

Metallic Inert Gas

Question 35

What is becoming the main welding process in the sheet metal industry?

Answer 35

GMAW

Question 36

What does GMAW stand for?

Answer 36

Gas Metal Arc Welding

Question 37

What does SMAW stand for?

Answer 37

Shielded Metal Arc Welding

Question 38

Which welding process uses more radiation? GMAW or SMAW

Answer 38

GMAW

Question 39

What is mandatory for all GMAW operations?

Answer 39

Adequate ventilation

Question 40

You must use extreme caution when working with what type of metals that contain these?

Answer 40

Zinc, cadmium, lead, and beryllium

Question 41

Fans or drafts of over ___ surface feet per minute may blow the protective gas envelope away from the weld zone, causing oxidation of the weld metal.

Answer 41

50 surface feet per minute

Question 42

All cylinders must have what attached to it?

Answer 42

A WHMIS symbol attached

Question 43

Which welding process uses a constant voltage (CV) power source that is used to supply a constant voltage no matter what the conditions are and has a wire feed mechanism that feeds wire at a constant rate to the weld zone?

Answer 43

GMAW

Question 44

More voltage requires?

Answer 44

Thicker wire and material

Question 45

More wire being supplied to the weld zone requires?

Answer 45

More heat to melt it

Question 46

What are the 3 basic types of metal transfer methods?

Answer 46

Short-circuit transfer, globular transfer, and spray arc transfer

Question 47

Which type of metal transfer methods should be avoided?

Answer 47

Globular transfer

Question 48

The welding of steel sheet metal, whether it is coated steel or stainless steel is accomplished through?

Answer 48

The short-circuit transfer method

Question 49

Which transfer occurs when the weld metal passes through an open arc in the form of large globules that are often larger in diameter than the filler wire?

Answer 49

Globular transfer

Question 50

What transfer occurs when using a direct current electrode positive (DCEP) with a shielding gas containing at least 85 percent argon and by increasing the welding current above a critical value called the transition current?

Answer 50

Spray transfer

Question 51

What type of transfer is a stream of tiny metal droplets crossing the welding arc from the filler wire to the base metal?

Answer 51

Spray transfer

Question 52

What does DCEP stand for?

Answer 52

Direct current electrode positive

Question 53

What does DCEN stand for?

Answer 53

Direct current electrode negative

Question 54

Current goes from ____ to ____?

Answer 54

Negative to positive

Question 55

The spray transfer method must have no less than ___ percent argon when welding carbon steel?

Answer 55

85 percent

Question 56

Voltage set the?

Answer 56

Arc length

Question 57

Wire speed sets the?

Answer 57

Heat

Question 58

If the voltage is too low or the wire speed is too high, you will get what is referred to as?

Answer 58

Stubbing

Question 59

What does FCAW stand for?

Answer 59

Flux cored arc welding

Question 60

What is referred to as a semiautomatic welding process?

Answer 60

FCAW

Question 61

Which type of welding produces a flux that must be removed, has good weld appearance, and creates smooth uniform welds?

Answer 61

FCAW

Question 62

Wires must be identified by?

Answer 62

Classification, batch number, wire and spool size

Question 63

What is the purpose of a shielding gas?

Answer 63

To prevent the molten weld metal from absorbing elements such as oxygen and nitrogen from atmospheric air.

Question 64

The atmosphere is made up of approximately?

Answer 64

1 percent argon, 21 percent oxygen, and 78 percent nitrogen

Question 65

What is the thermal conductivity of a gas?

Answer 65

It is its ability to conduct heat

Question 66

Argon gas has a low or high thermal conductivity?

Answer 66

Low thermal conductivity

Question 67

Helium has a low or high thermal conductivity?

Answer 67

High thermal conductivity

Question 68

What is a chemically inert gas that does not combine with the products of the weld zone. It is also a colourless, odourless, non flammable gas that acts as an asphyxiant which can cause suffocation?

Answer 68

Argon

Question 69

Argon is approximately ____ times heavier than air.

Answer 69

1.4 times

Question 70

Which is better fir welding thin sections? Argon or Helium?

Answer 70

Argon

Question 71

What gas is colourless, odourless, non-flammable and is derived from the processing of natural gas?

Answer 71

Helium

Question 72

The density of helium is about ___ that of air.

Answer 72

0.14 times

Question 73

What gas is used primarily for the non-ferrous metals such as aluminum, magnesium, and copper?

Answer 73

Helium

Question 74

Argon gas flow rates are usually set to?

Answer 74

20 to 25 cubic ft per hour (cfh)

Question 75

What are referred to as reactive gases?

Answer 75

Carbon dioxide, oxygen, hydrogen, and nitrogen

Question 76

What is a compound gas that is reactive, colourless, odourless, non flammable, and acts as an asphyxiant. It's elements are carbon and oxygen?

Answer 76

Carbon dioxide

Question 77

Carbon dioxide is ___ percent heavier than air.

Answer 77

53 percent

Question 78

What compound gas is often used for the short-circuiting and globular modes of metal transfer?

Answer 78

Carbon dioxide

Question 79

What is currently the cheapest shielding gas available?

Answer 79

Carbon dioxide

Question 80

What is a colourless, odourless, oxidizing gas that combines with with nearly all known elements?

Answer 80

Oxygen

Question 81

Added oxygen must be less then ___ percent.

Answer 81

10 percent

Question 82

What is a colourless, odourless, flammable gas that acts as an asphyxiant and is the lightest known element. It is also highly combustible in air or oxygen. It also burns with an almost invisible flame?

Answer 82

Hydrogen

Question 83

What is generally used for special applications such as joining stainless steel?

Answer 83

Hydrogen

Question 84

What gas is colourless, odourless, non-flammable, acts like an asphyxiant and is considered inert, but will react with some elements at high temperatures?

Answer 84

Nitrogen

Question 85

A widely used ratio of argon to carbon dioxide is?

Answer 85

75 percent argon with 25 percent carbon dioxide known as C25

Question 86

Any mixed gas containing ___ is not recommended for non-ferrous metals, as these metals are generally reactive.

Answer 86

Oxygen

Question 87

Welders prefer to use backup plates for materials up to?

Answer 87

1/4 " thick

Question 88

What wire diameters are commonly used for the spray process?

Answer 88

0.030" and 0.045"

Question 89

What transfer method must be used in order to minimize distortion when welding lighter gauge stainless steels?

Answer 89

The short circuit transfer weld mode is used

Question 90

What is of great importance for all types of stainless steel?

Answer 90

The need for cleaning prior to and after welding.

Question 91

What causes porosity?

Answer 91

Moisture

Question 92

Stainless steel has high or low thermal conductivity?

Answer 92

Low thermal conductivity

Question 93

What type of metal has a high coefficient of thermal expansion?

Answer 93

Stainless steel

Question 94

What is the most important aspect of welding austenitic stainless steels?

Answer 94

The selection of a filler wire having the correct alloy compostition.

Question 95

What is the second most commonly used metal?

Answer 95

Aluminum

Question 96

What is the number one commonly used metal?

Answer 96

Steel

Question 97

Aluminum is obtained from an ore called?

Answer 97

Bauxite

Question 98

What is the thermal conductivity of aluminum?

Answer 98

About half that of copper and almost four times higher than that of steel

Question 99

Aluminum requires a heat input ___ times more rapid than mild steel to raise its temperature to the melting point.

Answer 99

4 times more

Question 100

What is the melting point of aluminum?

Answer 100

660 degrees C (1220 degress F)

Question 101

What type of metal is non-magnetic and is often used to shield electronic equipment. It also does not spark and is used in the fabrication of storage containers?

Answer 101

Aluminum

Question 102

What electro-chemical process is used almost exclusively on aluminum?

Answer 102

Anodizing

Question 103

Aluminum's coefficient of expansion is almost ___ that of steel?

Answer 103

Twice that of steel

Question 104

To weld aluminum successfully, you must remove the?

Answer 104

Oxide layer

Question 105

For MIG welding alumiunum, you need to use a ___ to ___ push travel angle pointed in the direction of travel.

Answer 105

10 degress to 15 degrees

Question 106

GMAW is advantageous for welding aluminum material thicknesses greater than?

Answer 106

3.2 mm (1/8")

Question 107

Argon helium mixes are not required until the metal is more than?

Answer 107

1" (25mm) thick

Question 108

What welding process is preferred when weld appearance is not a concern?

Answer 108

GMAW

Question 109

What are the two types of power sources that can be used for GMAW on aluminum?

Answer 109

Constant voltage (CV) and constant current (CC)

Question 110

What power source is most often used for GMAW on aluminum?

Answer 110

Constant voltage (CV)

Question 111

Always use 100 percent of what shielding gas for best results on aluminum?

Answer 111

Argon

Question 112

What are the two most popular wires for welding aluminum?

Answer 112

ER4043 and ER5356

Question 113

What type of wire feeders are commonly used with aluminum?

Answer 113

Pull types, push types, or a combination of both