40 Questions
What is convexity in welding defined as?
The maximum distance from the face of a convex fillet weld perpendicular to a line joining the weld toes
What may excessive convexity lead to in multipass welds?
Notch effects
What are some probable causes of convexity in welding?
Incorrect work and travel angles
How can excessive convexity on fillet welds be corrected?
Grinding to achieve a flat weld profile
What is the maximum permitted reinforcement according to CSA Standard W59?
3mm (1/8 in)
How can insufficient throat in a fillet weld be corrected?
By adding more weld metal to the valley between successive weld beads
What is the probable cause of undercut discontinuities?
Joint accessibility and position
How should excessive undercut be prevented?
By proper welding procedures, techniques, joint preparation, and fit-up
What is the consequence of underfill in a weld?
Reduces load-carrying capacity
How can insufficient leg size in a fillet weld be corrected?
By depositing additional passes
What does surface undercut in a weld indicate?
It should be corrected
What is the consequence of convexity caused by insufficient heat input?
Requires complete removal of the weld and depositing a new weld
What is the potential consequence of excessive weld reinforcement?
Stiffens the section and establishes notches
When can undercut occur in the welding process?
At any stage of the welding process
How can underfill be caused in a weld?
By fast travel speed
How can the limitations of undercut be determined?
By governing codes and standards
What is concavity defined as in fillet welds?
The maximum distance from the face of a concave fillet weld to a line joining the weld toes
How can excessively concave fillet welds be corrected?
By adding more weld passes
What can cause concavity in fillet welds?
Operator techniques and welding parameters
How can the leg and throat size of concave fillet welds be measured?
With fillet weld gauges
What can result from out-of-line weld beads in a joint requiring complete joint penetration?
Incomplete joint penetration
What is incomplete fusion in welding?
The failure to fuse between weld metal and fusion faces or adjoining weld beads
What may cause incomplete fusion in welding?
Improper electrode selection, welding parameters, and joint design
How can weld deficiencies due to poor profile be detected?
Visually or by using suitable gauges
What is the consequence of out-of-line weld beads in a joint requiring complete joint penetration?
Incomplete joint penetration
What is the potential consequence of excessively concave fillet welds?
Reduced strength of the weld joint
What is the maximum permitted reinforcement according to CSA Standard W59?
1/8 inch
How can weld deficiencies due to insufficient or excessive size be detected?
Visually or by using suitable gauges
What is concavity defined as in a fillet weld?
The maximum distance from the face of a concave fillet weld to a line joining the weld toes
What can cause concavity in fillet welds?
Operator techniques and welding parameters
How can excessively concave fillet welds be corrected?
By adding more weld passes
What can result in incomplete joint penetration when complete joint penetration is required?
Out-of-line weld beads
What is incomplete fusion in welding?
The failure to fuse between weld metal and fusion faces or adjoining weld beads
How can weld deficiencies due to insufficient or excessive size and poor profile be detected?
Visually or by using suitable gauges
What can be used to measure the leg and throat size of concave fillet welds?
Fillet weld gauges
What may cause incomplete fusion in welding?
Improper electrode selection, welding parameters, and joint design
How can large diameter pipes with external undercut defects be repaired?
Using the same method as external undercut
What is shown in Figure 19 of the text?
Acceptable and unacceptable groove weld profiles
What is shown in Figure 23 of the text?
Desirable, acceptable, and unacceptable fillet weld profiles
What is the correct method for repairing small diameter pipe undercut defects?
Cutting out the section and preparing a new joint
Study Notes
Welding Defects and Corrections
- Large diameter pipes can be repaired using the same method as external undercut.
- Small diameter pipe undercut defects require cutting out the section and preparing a new joint.
- Acceptable and unacceptable groove weld profiles are shown in Figure 19.
- Concavity is defined as the maximum distance from the face of a concave fillet weld to a line joining the weld toes.
- Operator techniques and welding parameters can cause concavity in fillet welds.
- Excessively concave fillet welds can be corrected by adding more weld passes.
- Desirable, acceptable, and unacceptable fillet weld profiles are shown in Figure 23.
- Weld deficiencies due to insufficient or excessive size and poor profile may be detected visually or by using suitable gauges.
- The leg and throat size of concave fillet welds can be measured with fillet weld gauges.
- Out-of-line weld beads can result in incomplete joint penetration when complete joint penetration is required.
- Incomplete fusion is the failure to fuse between weld metal and fusion faces or adjoining weld beads.
- Incomplete fusion may be caused by factors such as improper electrode selection, welding parameters, and joint design.
Test your knowledge of welding discontinuities and defects with this quiz. Learn about the causes of discontinuities such as undercut, concavity, and incomplete fusion, as well as the corrective measures to address these issues. Understand the impact of welding parameters and joint preparation on weld quality.
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