120103e GMAW on Mild Steel

Question 1

Question: Is it necessary to remove scale and rust from the base metal? Explain your answer.

a) Yes
b) No

Answer 1

Answer: a) Yes; Remove excess oil, rust, scale, paint, or coatings to prevent contamination of the weld zone and reduce harmful fumes that may be produced.

Explanation: Removing impurities like scale and rust from the base metal is essential to avoid contamination of the weld and to minimize the production of harmful fumes during welding.

Question 2

Question: Describe a stringer bead.

Answer 2

Answer: A stringer bead is a type of weld bead created by moving the welding gun in a straight line with little or no side-to-side motion.

Explanation: Stringer beads are used to create a weld in a straight line. This technique is fundamental in welding, as it helps in producing a clean, uniform weld.

Question 3

Question: How should you lay beads when surface welding for buildup work?

a) Space them so they are 3.2 mm (1/8”) apart.
b) Blend them together so that they form a solid layer of weld metal.
c) Space them so they are 6.4 mm (1/4”) apart.
d) The toe of one bead should meet the toe of the next bead.

Answer 3

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

Explanation: When performing surface welding for buildup work, it’s important to blend the beads together to create a solid and continuous layer of weld metal. This ensures the structural integrity and uniformity of the welded surface.

Question 4

Question: In what positions can you do surface welding with GMAW using short-circuit metal transfer?

a) flat position only
b) flat and horizontal positions only
c) all positions except vertical
d) all positions

Answer 4

Answer: d) all positions

Explanation: GMAW with short-circuit metal transfer is versatile and can be performed in all welding positions, including flat, horizontal, vertical, and overhead.

Question 5

Question: What is the normal electrode angle when doing single-pass 1F welds?

a) 90° to the joint angle
b) 45° to the joint angle
c) 15° - 20° to the joint angle
d) 180° relative to the welder’s position

Answer 5

Answer: b) 45° to the joint angle

Explanation: For single-pass 1F welds, the normal electrode angle is 45° to the joint angle. This angle helps in achieving proper penetration and weld bead formation.

Question 6

Question: How is work positioned for a 1F Tee joint?

a) 90° and 0° to the horizontal plane
b) 180° and 360° to the horizontal plane
c) 120° and 60° to the horizontal plane
d) each member at 45° to the horizontal plane

Answer 6

Answer: d) each member at 45° to the horizontal plane

Explanation: In a 1F Tee joint, each member at 45° to the horizontal plane. This configuration is typical for a Tee joint in the flat position.

Question 7

Question: Given a choice, what position should you use to achieve the most productive fillet welding?

a) 4F
b) 1G
c) 1F
d) 6F

Answer 7

Answer: c) 1F

Explanation: The 1F position, where the workpiece is in the flat position, is typically the most productive for fillet welding. This position allows for easier manipulation of the welding gun and better control over the weld pool.

Question 8

Question: What is the recommended gun angle for the first pass of a 2F weld on 10 mm (3/8”) material with three stringer bead passes specified?

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 8

Answer: c) 45° to the vertical and horizontal planes

Explanation: For the first pass of a 2F weld on 10 mm material, a gun angle of 45° to both the vertical and horizontal planes is recommended. This angle helps ensure proper penetration and bead shape.

Question 9

Question: What type of bead is usually used for the cover pass on a 3F weld on 10 mm (3/8”) material?

a) weave bead
b) stringer bead
c) modified lazy L bead
d) long dwell crown bead

Answer 9

Answer: a) weave bead

Explanation: Weave beads are typically used for cover passes on 3F welds as they provide better control and consistent penetration, especially on thicker materials like 10 mm.

Question 10

Question: What is the likely weld progression for the first pass on a 3F weld on 10 mm (3/8”) material?

a) uphill
b) downhill
c) sleight of hand
d) back step

Answer 10

Answer: b) downhill

Explanation: Downhill progression is commonly used for the first pass in a 3F weld on thicker material to ensure adequate penetration and a strong foundation for subsequent passes.

Question 11

Question: What joint configuration is generally used for a 1G weld with a Vee groove preparation on 10 mm (3/8”) material?

a) 4 mm (s/32”) root face, 2.5 mm (3/32”) gap
b) 4 mm (5/32”) gap, 1.6 mm (’/i6”) root face
c) 4 mm (5/32”) root face, 4 mm C/32”) gap
d) 1.6 mm (Vie”) gap, 3.2 mm (’/g”) root face

Answer 11

Answer: b) 4 mm (5/32”) gap, 1.6 mm (’/i6”) root face

Question 12

Question: How many passes are generally used for a 1G weld with a Vee groove preparation on 10 mm (3/8”) material using 0.9 mm (0.35”) wire?

a) 3 or 4 passes
b) 5 or 6 passes
c) 6 or 7 passes
d) 1 or 2 passes

Answer 12

Answer: a) 3 or 4 passes

Explanation: Generally, 3 or 4 passes are sufficient for a 1G weld on 10 mm material with 0.9 mm wire, ensuring full penetration and proper bead profile.

Question 13

Question: What procedure is recommended to complete a 2G weld with a Vee groove preparation on 10 mm (3/8”) material?

a) Completely fill the joint with one large pass.
b) Use one root bead followed by one weave bead cover pass.
c) Use stringer beads on all fill and cover passes, working from the bottom upwards.
d) Use stringer beads on all fill and cover passes, working from the top downwards.

Answer 13

Answer: c) Use stringer beads on all fill and cover passes, working from the bottom upwards.

Explanation: Using stringer beads on all fill and cover passes from bottom to top ensures consistent penetration and avoids potential defects like lack of fusion.

Question 14

Question: The number and letter combinations of 1F and 2G represent:

a) the type of filler wire and shielding gas to be used for the project.
b) the position and type of weld to be completed.
c) the joint design and configuration.
d) the welding process and joint design to be used.

Answer 14

Answer: b) the position and type of weld to be completed.

Explanation: The number-letter combinations, such as 1F and 2G, indicate the position (1, 2, etc.) and the type of weld (F for fillet, G for groove) to be performed.

Question 15

Question: A WPS allows minor changes in the welding voltage and amperage.

a) true
b) false

Answer 15

Answer: a) true
Explanation: A Welding Procedure Specification (WPS) typically allows for minor changes in welding voltage and amperage.

Question 16

Question: The root pass is becoming excessively heavy as you weld a pipe in the 1GR position. What corrective action should you take while welding?

a) Work closer to the 12 o’clock position of the pipe.
b) Work closer to the vertical position, progressing downhill.
c) Slow the travel speed across the centre of the weld.
d) Incline the electrode more into the direction of travel.

Answer 16

Answer: b) Work closer to the vertical position, progressing downhill.

Question 17

Question: Single Vee preparations on pipe generally have an included angle within the range of:

a) 22.5° to 30°.
b) 30° to 45°.
c) 45° to 60°.
d) 60° to 75°.

Answer 17

Answer: d) 60° to 75°.

Explanation: Single Vee preparations on pipe typically have an included angle between 60° to 75°, which provides adequate access for welding while ensuring good penetration and weld quality.

Question 18

Question: Do all tack welds become an integral part of the weld? Explain your answer.

Answer 18

Answer: No; Bridged tacks must be removed as welding progresses. Tacks in the root that may become part of the root must be fully penetrated and feathered to ensure full fusion.

Question 19

Question: Where should the four tack welds be located on a 150 mm (6”) pipe to be welded in the 5G position?

Answer 19

Answer: The tacks are generally located at the 12, 3, 6, and 9 o’clock positions.

Explanation: The placement of tack welds in these positions helps in maintaining alignment and stability of the pipe during welding in the 5G position.

Question 20

Question: What is the maximum length of tack welds used for joining 150 mm (6”) sch. 80 pipe?

Answer 20

Answer: 19 mm (3/4”)

Explanation: The maximum length of tack welds for joining such pipes is 19 mm (3/4”), which provides sufficient hold without being excessively large.

Question 21

Question: If a pipe is fit so that the gap is not uniform, at what location should the widest portion of the gap be placed in preparation for welding?

Answer 21

Answer: The widest gap should be placed at or near the last quarter of the joint to be welded.

Explanation: Placing the widest gap at the end of the welding sequence allows for easier adjustment and better control during the welding process.

Question 22

Question: On an 80 mm (3”) sch. 40 pipe, what is the minimum number and length of tacks required?

a) 2 tacks at 25.4 mm (1”) long
b) 2 tacks at 12.7 mm (1/2”) long
c) 3 tacks at 12.7 mm (1/2”) long
d) 4 tacks at 25.4 mm (1”) long

Answer 22

Answer: c) 3 tacks at 12.7 mm (1/2”) long

Explanation: For an 80 mm sch. 40 pipe, a minimum of three tacks each 12.7 mm (1/2”) long is required to ensure proper alignment and stability.

Question 23

Question: What is the root gap between the test plates for a CWB 2G test weld?

a) 6.4 mm (1/4”)
b) 8 mm (5/16”)
c) 10 mm (3/8”)
d) 13 mm (1/2”)

Answer 23

Answer: b) 8 mm (5/16”)

Explanation: For a Canadian Welding Bureau (CWB) 2G test weld, the specified root gap between the test plates is 8 mm (5/16”).

Question 24

Question: How far are the stop/starts from the edge of the CWB 4GF test plate?

a) 13 mm (1/2”)
b) 19 mm (3/4”)
c) 25.4 mm (1”)
d) 38 mm (1 1/2”)

Answer 24

Answer: d) 38 mm (1 1/2”)

Explanation: The stop/starts on a CWB 4GF test plate should be 38 mm (1 1/2”) from the edge, which is a standard practice to ensure proper welding techniques and quality.