Visual Examination and Discontinuities Flashcards
Learn what causes and how to identify discontinuities like laminations, cracks, inclusions and lack of fusion.
The internal misalignment of pipe ends (high-low) may result in what discontinuity?
Inadequate penetration
What discontinuity is shown here?
Inadequate penetration
The discontinuity caused by weld metal that does not extend through the thickness of the joint is called:
Inadequate penetration
What discontinuity is shown here?
Inadequate penetration
The discontinuity caused when travel speed is too slow causing weld metal to overflow onto the base metal is called:
Overlap
An excessively convex fillet weld creates what discontinuity?
Overlap
What discontinuity is shown here?
Overlap
The three types of porosity (besides isolated porosity) are:
Cluster, piping and elongated
What discontinuity is shown here?
Aligned porosity
A localized array of porosity oriented in a line is called:
Aligned porosity
The discontinuity that results from gas being trapped in the weld during solidification is called:
Porosity
The use of wet low hydrogen electrodes may result in what discontinuity?
Porosity
What discontinuity is shown here?
Elongated porosity
What discontinuity is shown here?
Arc strike
Can arc strikes be repaired?
No
The discontinuity that results from the initiation of the arc outside the weld zone is called:
Arc strike
What are the two most common types of inclusions?
Tungsten and slag
Inclusions are of what two types?
Metallic and non-metallic
Entrapped foreign solid material, such as slag, flux, tungsten or oxide is called:
Inclusion
Excessive amperage, travel speed and improper work angel may cause what discontinuity?
Undercut
What discontinuity only appears in the weld interface adjacent to the weld toe or weld root?
Undercut
What discontinuity is shown here?
Undercut
When the base metal is melted but not filled in with weld metal, _______ results at the toes of the weld.
Undercut
The discontinuity that results when the root of a single V-groove weld is blown inwards is called:
Burn through
A hole or depression in the root bead of a single-groove weld due to excess penetration is called:
Burn through
What discontinuity is shown in this root bead?
Burn through
Metal particles that adhere to the base metal but are not incorporated into the weld describes which discontinuity?
Spatter
What discontinuity is shown here?
Spatter
In general, do grinding repairs require the inspectors approval?
No
Fusion over the entire fusion faces and between all adjoining weld beads is called:
Complete fusion
What discontinuity is shown here?
Incomplete fusion of a consumable insert
What discontinuity is shown here?
Incomplete fusion
The discontinuity that results when a weld bead does not combine with the base metal is called:
Incomplete fusion
What discontinuity occurs just outside the HAZ and is characterized by a step-like appearance?
Lamellar tears
A subsurface terrace and step-like crack in the base metal caused by tensile stresses in the through-thickness direction of the base metal is called:
Lamellar tear
Which discontinuity is caused by shrinkage stress in the through thickness direction of a thick plate?
Lamellar tear
What discontinuity is shown here?
Lamellar tear
Hydrogen in the weld pool may cause what two discontinuities?
Cracking and porosity
What type of crack is shown here?
Throat crack
The presence of hydrogen, a susceptible microstructure, stress and low temperature are the four requirements for delayed cracks to form in what area?
The HAZ
heat affected zone
A crack that runs perpendicular to the weld is called a:
Transverse crack
Materials prone to hydrogen embrittlement are not inspected for at least 48 hours after welding is completed because they are prone to:
Delayed (hydrogen) cracking
Which discontinuity is considered the most detrimental?
Cracks
What type of discontinuity is shown here?
Crater crack
What type of discontinuity is shown here?
HAZ (heat affected zone) crack
A fracture-type discontinuity characterized by a sharp tip and high ratio of width and length to opening displacement is called:
A crack
Improper width-to-depth ratio of the molten weld pool can result in what type of cracking?
Solidification cracking
Delayed cracking may occur up to ____ hours after the weld is completed.
48 hours
This solidification crack was caused by what?
Improper width-to-depth ratio
What type of discontinuity is shown here?
Longitudinal crack
What type of discontinuities appear in the HAZ (heat affected zone)?
Cracks
Crater cracks are most often caused by what?
Improper termination of the arc
Underbead cracking is primarily caused by:
Hydrogen
The discontinuity that results in the separation of a lamination under stress is called:
Delamination
What mill-induced discontinuity is being shown in this rolled plate?
Laminations
The mill-induced discontinuity with a separation or weakness toward the center of rolled products is called:
A lamination
What mill-induced discontinuities appear on the surface of rolled products?
Seams and laps
Which discontinuities are caused by improper manufacturing of the base material?
Laminations, seams and laps
Thermocouples, crayons and surface pyrometers are all ways to monitor what?
Preheat and interpass temperature
What inspection tool is shown here?
A pyrometer
In a multipass weld, the temperature of the weld area prior to depositing the next weld bead is called what?
Interpass temperature
Preheat should always be measured ___ inches from the edge of the weld zone.
3”
What discontinuity is shown here?
Suck back (concave root)
In pipe welding, surface tension of the molten weld metal tries to pull itself into a ball, forming a concave root surface. This discontinuity is referred to as:
Suck back (concave root)
The discontinuity that results when the weld metal is below the surface of the base metal is called:
Underfill
What discontinuity is shown here?
Underfill
Excessive buildup on the face of a groove weld is called:
Excessive reinforcement
The height of the weld above the base metal in a groove weld is called:
Reinforcement
What discontinuity is shown here?
Excessive reinforcement
A discontinuity that renders a part unable to meet certain acceptance criteria is called:
A defect
Which weld bead uses a higher amperage and faster travel speed to smooth the root bead and burn out trapped slag?
Hot pass
An interruption of the typical physical characteristics of a weldment describes what?
Discontinuity
A ______ is always a discontinuity, but a discontinuity is not always a ________.
Defect
Freedom from imperfection describes a materials:
Soundness
A delay in welding to allow inspection is called what?
Hold point
Machining the I.D. of pipe ends for proper alignment is know as:
Counterbore
The machining that has been done to the end of this pipe is called what?
Counterbore
When should VT (visual testing) be performed?
Before, during and after welding
The least expensive form of NDE is:
VT
visual testing
Which NDE method can verify fit-up, joint configuration, weld dimensions and profile?
VT
visual testing
What is the most frequently used NDE method?
VT
visual testing
Light is measured in what increments?
Foot candles
This type of picture is used for what type of test?
Color-blindness
What type of NDE is being conducted here?
VT
visual testing
A borescope may be used with what type of NDE?
VT
visual testing
What type of NDE uses a light source, magnifyers, and rulers?
VT
visual testing
What problems may result if the welding amperage is too high?
Excessive spatter and porosity
An excess of dross on a torch cut surface implies what?
Travel speed too slow
When should drawings and specifications be reviewed?
Before, during and after welding
What does this guage measure?
High-low (misalignment)
What does this gauge measure?
Root opening
The item placed between the two unwelded pipes is called what?
Consumable insert
Pre-placed filler metal that is incorporated into the root bead during welding is called:
Consumable insert
What pipe schedule is ‘standard’ wall thickness?
Schedule 40
What do these gauges measure?
Fillet weld size
Which leg of the fillet is being measured in this picture?
The vertical leg
Which leg of the fillet is being measured in this picture?
The horizontal leg
”+/-“ is used to express what?
Tolerance
Does the CWI need to particiapte in good housekeeping?
Yes
Does the CWI make visual inspection criteria?
No
Does the CWI participate in creating a QC program?
Yes
How should errors on inspection reports be corrected?
Single line out and initial
Should the CWI publicly express opinions on workmanship?
No
The acronym MTR stands for what?
Material test report
Is preheat a minimum, maximum or range of temperature to be maintained during welding?
Minimum
Is interpass a minimum, maximum or range of temperature to be maintained during welding?
Maximum
The AWS requires that all welding inspectors have at least what vision?
20/40 with or without correction
When a defect is found and a repair is necessary, who should the inspector give his report to?
The welding foreman or supervisor
In general, low-hydrogen electrodes may only be out of the oven for how long?
4 hours
Codes, standards, specifications and recommended practices may all contain what?
Job requirements
Which document is legally binding?
A code
When a welder is consistently making welds that are marginally acceptable, when should you speak to the welder about the problem?
Never
Can hydrogen cause lamellar tears?
No
What is a discontinuity?
An interruption in the typical structure of the material
What is a defect?
A discontinuity that exceeds the limits of the specification
This tensile specimen shows what mill induced discontinuity?
Delamination
This fillet weld shows what discontinuity?
Lack of fusion (it’s not a crack; it isn’t melted to the plate)
This porosity was most likely caused by what?
Hydrogen entrapment (wet electrodes)
Which mill induced discontinuity can be seen here?
Seam or Lap
What is this discontinuity?
Burn-through
