Welding

Question 1

What does GMAW

Answer 1

Gas metal arc welding

Question 2

What is DCEP

Answer 2

Direct current, electrode positive

Question 3

What is the “mode of metal transfer”?

Answer 3

The way that the weld metal transfers across the arc from the end of the electrode to the weld zone

Question 4

What are the 3 different basic modes of metal transfer?

Answer 4

• short-circuiting transfer
• globular transfer
• spray transfer

Question 5

What are the 5 factors that determine the mode of metal transfer?

Answer 5

• weld current
• filler wire diameter
• arc length (heat control)
• type of shielding
• position of welding

Question 6

Which type of welding produces the least amount of spatter?

Answer 6

Spray arc welding (spray transfer)

Question 7

What kind of welding occurs when there is a 85% argon or higher?

Answer 7

Spray transfer

Question 8

What is the transition current?

Answer 8

?

Question 9

Which has a higher arc voltage:

Spray transfer or short circuit transfer?

Answer 9

Spray transfer?

Question 10

What is globular transfer?

Answer 10

When the metal passes through an open arc in the for of large globules

Question 11

What is the current setting for globular transfer?

Answer 11

Between short-circuiting and spray transfer

Question 12

What size wire is used in short-circuiting metal transfer?

Answer 12

0.023-0.045”

Question 13

How does short-circuiting metal transfer work?

Answer 13

The filler wire makes Direct contact with the base metal, creating a short-circuit in the arc. It then melts off and melts into the base metal

Question 14

What are the advantages of short-circuiting welding?

Answer 14

• Minimum distortion due to low heat
• Ideal for joining light gauge metals
• And for fit-ups with wide gaps

Question 15

What is most common power source used for most GMAW applications?

Answer 15

DCEP- direct current, electrode positive

Question 16

What is AWS?

Answer 16

American welding society

Question 17

What is the primary function of the shielding gas?

Answer 17

To shield the molten weld metal from atmospheric contamination

Question 18

What gas is used for:
Aluminum:?
Carbon and low-alloy steels?

Answer 18

Range from argon or helium.

Steel- mixture of Argon and CO2

Question 19

What is the purpose of the regulator?

Answer 19

It’s responsible for reducing the gas source pressure to a constant working pressure

Question 20

What does the flow meter do?

Answer 20

They are calibrated to indicate a volumetric flow rate in L/min or CFM (cubic feet per minute)

Question 21

What is the pressure of a full cylinder at room temp?

Answer 21

Approx. 2000 psi

Question 22

What should you do before installing the regulator onto the tank?

Answer 22

Should crack the cylinder valve for a second to blow any dirt or dust away

Question 23

What is the recommended rate of flow for the gas?

Answer 23

15-35 CFH

Question 24

What are considered Inert gas?

Answer 24

Argon, helium, and CO2

Question 25

What should you mark on an empty bottle?

Answer 25

“MT” with a soapstone

Question 26

What is the electrode angle refer to? | And what should it be?

Answer 26

Refers to the position of the wire in relation to the included joint angle Should be on half of the included joint angle

Question 27

What is it called when you fail to fill the parent metal after melting it away?

Answer 27

Undercut

Question 28

AWS-ER-70S-6 | What does each letter stand for?

Answer 28

AWS- American welding society? E- designated Electric welding R-designated it as a filler rod 70-tensile strength in thousands of pounds per inch S- designates solid wire (T is for flux core or tubular wire) 6- designated wire characteristics (6: all positions)

Question 29

What is the electrode that we use in the shop

Answer 29

AWS-ER-70S-6

Question 30

What is electrode inclination?

Answer 30

It’s the position of the electrode to the work piece in relation to the direction of travel

Question 31

Which type of weld produces a flatter bead shape with less penetration?

Answer 31

A forehand inclination

Question 32

What type of inclination creates a narrower bead with a higher crown?

Answer 32

A backhand inclination

Question 33

What is the weld with the maximum penetration?

Answer 33

A 15-20 degree backhand inclination?

Question 34

What is electrode extension and what is recommended?

Answer 34

Distance from the end of the contact tube to the end of the wire? 3-8”

Question 35

What is the recommended electrode angle for a flat butt weld?

Answer 35

90 degrees

Question 36

What is the recommended placement for the nozzle end?

Answer 36

Flush with the contact tube

Question 37

What may be the issue if you aren’t getting a good weld and lots of splatter?

Answer 37

Contact tip is off centre so it changes the pattern of the shielding gas flow

Question 38

What is a cause of porosity and poor quality welds?

Answer 38

Splatter build up on the nozzle creating gas flow turbulence

Question 39

What is used to direct the shielding gas onto the weld zone?

Answer 39

The nozzle

Question 40

What can a bad ground cause?

Answer 40

Can cause an unstable arc

Question 41

What should be done before welding on any vehicle or trailer?

Answer 41

Disconnect all batteries

Question 42

What is it called when the electrode comes in contact with the base metal and fails to start and arc immediately? What can be the causes for it?

Answer 42

``` Called “stubbing” Can be caused by: excessive wire feed speed, Low arc voltage or Heavily scaled base metals ```

Question 43

When should the conduit liner be cleaned of any wire?

Answer 43

Every time you change the spool

Question 44

What can a badly worn or dirty contact tip cause?

Answer 44

Arc hunting

Question 45

What is the cause of a porosity, black, saggy weld

Answer 45

Lack of shielding gas

Question 46

What refers to the pockets of gas entrapped within the weld metal?

Answer 46

Porosity

Question 47

What happens when you carry a large bead with slow travel speed where the wire rides onto of the puddle?

Answer 47

Cold starts! It will not penetrate properly

Question 48

What is the “root”

Answer 48

It is the bottom of your weld with the most penetration

Question 49

What is produced when welding galvanized metals?

Answer 49

Zinc oxide

Question 50

What shade of welding tint in minimum and what is suggested?

Answer 50

#10 is the minimum but CSA+AWS suggest a #11

Question 51

What kind of clothing should be worn when welding?

Answer 51

``` 100% cotton Dark colour to reduce reflection Tight knit Gauntlet style gloves Steel toed, leather safety boots Welding mask ```

Question 52

What kind of ventilation should you have when welding?

Answer 52

A low-velocity suction hood or something that will not disturb the welding gas