QC 1
What is a Discontinuity?
Any observable interruption in the weld metal or base metal
What is a defect ?
A discontinuity that has been evaluated and determined to exceed the applicable acceptance criteria and relevant code.
A defect is a rejectable discontinuity
The three groups of weld discontinuities are ?
Geometric or dimensional
Structural discontinuities
Property deficiencies or defective
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Bead irregularities are discontinuities that may be considered defect TRUE?FALSE
TRUE Page 34
Misalignment of the weld can be caused by?
Insufficient care in positioning automatic welding machines
incorrect bead placement
incorrect edge preparation
inaccurate back gouging Page 34
What is the corrective action for a under filled weld?
The corrective action is to grind down the original weld face and then recap the weld.
Suck back on the root happens with which process ?
Gas tungsten arc welding
A concave root surface can happen when ?
Excessive arc length
Insufficient metal being applied
Failure to tail out at the end of a tie in
Improper welding parameters
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Some causes of burn through are ?
Improper root preparation PAGE 36
Insufficient travel speed
Excessive amperage
Excessive arc force
Incorrect work angle
Excessive convexity tends to produce _________in multi pass welds ?
Notch effect in multi pass welds
The definition for excessive reinforcement is defined as?
The area that has weld metal added more than what is permitted by the code or standard.
AWS D1.6 CSA W 59 all permit a maximum reinforcement of __________ for groove welds.
3.2mm or (1/8)
What is the definition of under cut ?
The melting away of the parent metal during the welding process ?
What are some of the causes of under cut ?
incorrect work angle ,travel angle, or travel speed
incorrect voltage or amperage
incorrect joint preparation
What are examples of structural discontinuities ?
Porosity,lack of fusion,incomplete penetration
Cracking ,Arc strike
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Cold lap is a condition of ?
Lack of fusion Page 40
Where are slag inclusion typically located ?
Slag inclusion are located at the edges of the weld
deposits. Page 41
The main causes of slag inclusion are ?
Improper preparation of the root pass
Lack of cleaning prior to the hot pass
Improper restart Tie -in
Improper inter pass cleaning
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The bright white spots in a welding X ray are caused using what process in welding ?
GTAW The bright white spots are tungsten inclusions.
Dark indications in a X RAY are likely __________
inclusion from incorrect inter pass cleaning?
Porosity or slag
What should you do if the contact tip or nozzle come into contact with the weld pool ?
Stop welding and grind out the contaminated area.
The pipe or tube is filled with a constant supply of inert gas during welding to keep out oxides from forming what is this called ?
Purging Page 43
What are the tracks that form along the edges(toes) of a root bead preformed with a fast freeze electrode called ?
Wagon tracks
Is described as gas pockets that are trapped in the solidifying weld metal ?
Porosity
What are the types of porosity ?
Uniformly scattered porosity
Cluster porosity,Linear porosity, Elongated porosity
Worm hole porosity, Worm tracks
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