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CWB WELDING INSPECTOR LEVEL 3 EXAM NEWEST 2025/2026
ACTUAL EXAM WITH COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (100% VERIFIED ANSWERS) |ALREADY
GRADED A+| ||PROFESSOR VERIFIED||
What is % parent metal dilution for a butt joint with V groove ? -
ANSWER-Dilution of parent metal will have much less effect and
the weld bead composition will be moved significantly out of the
crack sensitive region.
What is the dilution for T-joint fillet welds ? - ANSWER-10 %, the
weld bead composition will approach the filler alloy composition.
To allow a filler alloy to minimize cracking, the actual weld bead
composition should be as close to the filler alloy composition as
possible.
Why is for high temp applications, the Mg is kept below 3% ? -
ANSWER-To avoid exfoliation corrosion and stress corrosion
cracking
Which is the highest strength structural alloy ? - ANSWER-AA-
2219
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Which is the highest welded strength alloy ? - ANSWER-AA-7005
True/False
The welded strength of medium to high Mg bearing alloys of the
non-heat treatable alloys have higher strengths than the heat-
treatable alloys - ANSWER-Treu
What is the cause for weld bead cracking in Al ? - ANSWER-Hot
shortness of Al
What are the properties of Al ? - ANSWER-1. low density
2. Corrosion resistance
3. High electrical resistance
4. High thermal conductivity
5. good appearance
6. toughness at low temps
True / False ?
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Al is covered with a coherent oxide. - ANSWER-True
Thermal conductivity of Al is _______ times that of Steel -
ANSWER-4
Melting point of Al is about _______ of Steel - ANSWER-half
Coefficient of thermal expansion for Al is about _______ that of
Steel - ANSWER-twice
Modulus of elasticity (stiffness) for Al is about _______ that of
Steel - ANSWER-one-third
True / False
"Nitrogen is not inert to Al and is not used for sheilding" -
ANSWER-True
What is responsible for Al's excellent corrosion resistance? -
ANSWER-Al oxide but it changes to Magnesium oxide (MgO) or
Magnesium spinel ( Mg Al2O4) when the Mg % exceeds 0.05%.
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What is the thickness of Al oxide on the surface of Al ? -
ANSWER-50-150 angstroms
True/ False ?
The form of magnesium oxide is a function of the magnesium
concentration and the thermal history of the alloy - ANSWER-True
True / False ?
The oxide transformation from aluminum oxide to magnesium
oxide or magnesium spinel ,has a profound effect on the solid -
state bonding b/w any clad and the Al base - ANSWER-True
The solid -state bonding b/w Al and another metal or another
Aluminum alloy generally requires a control of the magnesium
level to ____ % - ANSWER-Less than 0.05%
Why does Mg has the profound influence on the oxide found on
Al? - ANSWER-1. Mg has a greater affinity than Al for O2.
CWB WELDING INSPECTOR LEVEL 3 EXAM NEWEST 2025/2026
ACTUAL EXAM WITH COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (100% VERIFIED ANSWERS) |ALREADY
GRADED A+| ||PROFESSOR VERIFIED||
What is % parent metal dilution for a butt joint with V groove ? -
ANSWER-Dilution of parent metal will have much less effect and
the weld bead composition will be moved significantly out of the
crack sensitive region.
What is the dilution for T-joint fillet welds ? - ANSWER-10 %, the
weld bead composition will approach the filler alloy composition.
To allow a filler alloy to minimize cracking, the actual weld bead
composition should be as close to the filler alloy composition as
possible.
Why is for high temp applications, the Mg is kept below 3% ? -
ANSWER-To avoid exfoliation corrosion and stress corrosion
cracking
Which is the highest strength structural alloy ? - ANSWER-AA-
2219
,2|Page
Which is the highest welded strength alloy ? - ANSWER-AA-7005
True/False
The welded strength of medium to high Mg bearing alloys of the
non-heat treatable alloys have higher strengths than the heat-
treatable alloys - ANSWER-Treu
What is the cause for weld bead cracking in Al ? - ANSWER-Hot
shortness of Al
What are the properties of Al ? - ANSWER-1. low density
2. Corrosion resistance
3. High electrical resistance
4. High thermal conductivity
5. good appearance
6. toughness at low temps
True / False ?
,3|Page
Al is covered with a coherent oxide. - ANSWER-True
Thermal conductivity of Al is _______ times that of Steel -
ANSWER-4
Melting point of Al is about _______ of Steel - ANSWER-half
Coefficient of thermal expansion for Al is about _______ that of
Steel - ANSWER-twice
Modulus of elasticity (stiffness) for Al is about _______ that of
Steel - ANSWER-one-third
True / False
"Nitrogen is not inert to Al and is not used for sheilding" -
ANSWER-True
What is responsible for Al's excellent corrosion resistance? -
ANSWER-Al oxide but it changes to Magnesium oxide (MgO) or
Magnesium spinel ( Mg Al2O4) when the Mg % exceeds 0.05%.
, 4|Page
What is the thickness of Al oxide on the surface of Al ? -
ANSWER-50-150 angstroms
True/ False ?
The form of magnesium oxide is a function of the magnesium
concentration and the thermal history of the alloy - ANSWER-True
True / False ?
The oxide transformation from aluminum oxide to magnesium
oxide or magnesium spinel ,has a profound effect on the solid -
state bonding b/w any clad and the Al base - ANSWER-True
The solid -state bonding b/w Al and another metal or another
Aluminum alloy generally requires a control of the magnesium
level to ____ % - ANSWER-Less than 0.05%
Why does Mg has the profound influence on the oxide found on
Al? - ANSWER-1. Mg has a greater affinity than Al for O2.
