120202d GTAW on Mild Steel

Question 1

How should you lay the beads when surface welding for buildup work?
a) Space them so that they are 3.2 mm (1/8”) apart.
b) Blend them together so they form a solid layer of weld metal.
c) Space them so that they are 6.4 mm (1/4”) apart.
d) The toe of one bead should meet the toe of the next bead.

Answer 1

b) Blend them together so they form a solid layer of weld metal.

Question 2

Is it necessary (yes or no) to remove the following from the mild steel base metal before welding with GTAW?
a) mill scale
b) loose rust
c) oil
d) varnish
e) soapstone markings

Answer 2

a) No, but it can be done to reduce undercut on the cap pass.
b) Yes
c) Yes
d) Yes
e) No, they do not interfere with GTAW applications.

Question 3

Identify the following for GTAW on mild steel.
a) most common electrode type:
b) electrode preparation shape:
c) current type:

Answer 3

a) EWTh-2
b) conical
c) direct current straight polarity

Question 4

What shielding gas is most often used for GTAW on mild steel?

Answer 4

argon

Question 5

What size of gas nozzle is recommended for any GTAW application?

Answer 5

the smallest nozzle whose lip does not melt in the heat of the arc, yet allows good visibility and adequate gas shielding

Question 6

An appropriate electrode stickout for GTAW:
a) prevents good visibility in all positions.
b) allows you to maintain a long arc.
c) causes atmospheric contamination of the electrode.
d) maintains a gas shield around the electrode and molten weld metal.

Answer 6

d) maintains a gas shield around the electrode and molten weld metal.

Question 7

Using the GTAW process, complete Table 15 with one advantage and one disadvantage for each method of striking the arc.

Answer 7

Table 16 shows an advantage and disadvantage of each method.

Question 8

Name two (2) techniques used for adding filler rod with GTAW.

Answer 8

a) dip feed technique
b) continuous feed technique

Question 9

Draw a sketch to demonstrate the inclination of the torch with the filler rod placement using GTAW in the flat position.

Answer 9

Figure 67 shows the correct torch inclination.

Question 10

Changing the inclination of the electrode holder in relation to the direction of travel:
a) changes the depth of penetration of the weld.
b) has no effect on the weld.
c) causes the filler rod to freeze in the puddle.
d) causes the filler rod to melt prematurely.

Answer 10

a) changes the depth of penetration of the weld.

Question 11

In what position(s) can you do surface welding with GTAW?
a) vertical position only
b) flat and horizontal positions only
c) all positions except vertical
d) all positions

Answer 11

d) all positions

Question 12

Describe the purpose of tailing out prior to breaking the arc.

Answer 12

The purpose of tailing out on the stop is to prevent cracking in the weld crater.

Question 13

How is the work positioned for a IF Tee joint?
a) 90° and 0° relative to the horizontal plane
b) 180° and 360° relative to the horizontal plane
c) 120° and 60° to the horizontal plane
d) each member at 45° to the horizontal plane

Answer 13

d) each member at 45° to the horizontal plane

Question 14

Given the choice, what position should you use for the most productive fillet welding?
a) 4F
b) 3F
c) 1F
d) 6F

Answer 14

c) 1F

Question 15

What is the recommended electrode angle for a 2F weld on 10 gauge material?
a) 90° to the vertical plane
b) 90° to the horizontal plane
c) 45° to the vertical and horizontal planes
d) 270° to the welder’s initial position prior to arc ignition

Answer 15

c) 45° to the vertical and horizontal planes

Question 16

What is the likely weld progression for a single pass 3F weld on 10 gauge material with GTAW?
a) uphill
b) downhill
c) saw tooth weave
d) back step

Answer 16

a) uphill

Question 17

Asa general rule, at what thickness of material should joint preparation be considered for full penetration groove welds when using GTAW?
a) 2.5 mm (3/32”)
b) 4.8 mm(3/16”)
c) 6.4 mm (1/4”)
d) 9.6 mm (3/8”)

Answer 17

b) 4.8 mm (3/16”)

Question 18

How long should the tack welds be for the plate weld projects in this module?
a) 2.5 mm - 3.2 mm (3/32” - 1/8”)
b) 3.2 mm - 4 mm (1/8” - 5/32”)
c) 6.4 mm - 9.6 mm (1/4” - 3/8”)
d) 12.8 mm- 19 mm (1/2”- 3/4”)

Answer 18

c) 6.4 mm - 9.6 mm (1/4” - 3/8”)

Question 19

What is the recommended electrode inclination for the 1G weld?
a) 0° - 15° forehand
b) 0° - 15° backhand
c) 20° - 30° forehand
d) 20° - 30° backhand

Answer 19

a) 0° - 15° forehand

Question 20

Describe the dip technique of adding filler rod.

Answer 20

In the dip technique, the filler rod is added at the leading edge of the puddle until the desired fill is attained and then removed from the puddle to progress forward.

Question 21

What is fall-through?
a) a technique for adding filler rod in the root bead
b) a low crater at the end of the weld
c) a localized area of excessive penetration
d) crater cracking as the result of failing to tail out

Answer 21

c) a localized area of excessive penetration

Question 22

What is the maximum electrode extension used for GTAW? Why?

Answer 22

Do not extend the electrode beyond 6.4 mm (‘/4”) because this may result in
inadequate gas coverage.

Question 23

What is likely to happen if a keyhole forms in the 1G position?
a) full fusion and penetration
b) lack of fusion
c) the electrode melts off into the puddle
d) fall-through

Answer 23

d) fall-through

Question 24

What is meant by suck-back and how may it occur?

Answer 24

Suck-back refers to an area of root bead that has been drawn into the groove leaving the root side concave in contour. This is generally caused by overheating the root pass during the second pass application. Suck-back during the welding of the root pass is caused by:
* travel speed too slow
* high current settings for overhead positions
* excessive arc length or
* failure to add Filler rod deep enough into the backside of the groove.

Question 25

State three (3) actions that may be used to increase root bead penetration.

Answer 25

Any three (3) of the following are correct.
a) Change the electrode inclination.
b) Slow the travel speed.
c) Shorten the arc length.
d) Increase amperage settings.
e) Add filler metal closer to the back of the groove preparation.
f) Change the configuration of the land and gap.

Question 26

In multi-pass welds, which pass is more susceptible to cracking?
a) the first filler pass
b) the cap pass
c) the second filler pass
d) the root pass

Answer 26

d) the root pass

Question 27

A procedure used to help prevent weld bead crater cracking is:
a) tailing out prior to breaking the arc.
b) using a shorter arc.
c) increasing the electrode angle.
d) breaking the arc and removing the filler rod as quickly as possible.

Answer 27

a) tailing out prior to breaking the arc.

Question 28

Draw a sketch to illustrate the filler rod placement to obtain full penetration while
welding in the 1G and 3G positions using the continuous feed technique.

Answer 28

Figure 68 shows the correct filler rod placement.

Question 29

What is the purpose of pre-setting the 2G weld on plate?
a) It makes them easier to tack.
b) It compensates for the shrinkage caused by stringer bead multi-pass welding.
c) It makes the groove wider for better penetration.
d) The weld edges can be seen more clearly.

Answer 29

b) It compensates for the shrinkage caused by stringer bead multi-pass welding.

Question 30

What is the recommended bevel angle range for a single Vee groove weld preparation on pipe?
a) 10°-15°
b) 15°-22.5°
c) 30°-37.5°
d) 60°-75°

Answer 30

c) 30°-37.5°

Question 31

How many tacks are recommended for joining 150 mm (6”) nominal pipe size?
a) 2
b) 3
c) 4
d) 6

Answer 31

c) 4

Question 32

If the gap is unequal after the first two tacks have been placed on a pipe joint, you should:
a) cut the joint apart and start the joint preparation all over again.
b) place the third tack on the tight side to even out the gap.
c) place the third tack at the widest location to even out the gap.
d) use a sledge hammer to even out the gap.

Answer 32

c) place the third tack at the widest location to even out the gap.

Question 33

Which of the following would be most effective in reducing accidents caused by portable grinders kicking back?
a) Keep both hands on the grinder and clamp the work.
b) Keep the grinder in contact with the work from start to stop.
c) Place the grinder on a flat surface until it stops rotating.
d) Keep one hand on the grinder while holding onto the work with the other.

Answer 33

a) Keep both hands on the grinder and clamp the work.