CWI NDE Methods and Symbols Questions and Answers — Questions and Answers
Question 1: A welding blueprint has a symbol in the tail of the reference line that reads 'UT'. This indicates that the weld requires which of the following?
- Visual Testing to check for surface discontinuities.
- Magnetic Particle Testing to find near-surface defects in ferromagnetic materials.
- Ultrasonic Testing to detect internal and sub-surface discontinuities. (Correct answer)
- Radiographic Testing to create a film image of the weld's internal structure.
Correct answer: Ultrasonic Testing to detect internal and sub-surface discontinuities.
According to AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination, letter designations are used in the tail of the welding symbol to specify the NDE method. 'UT' is the standard abbreviation for Ultrasonic Testing, which uses high-frequency sound waves to detect internal flaws.
Question 2: A CWI is reviewing a welding procedure for a critical application on a non-ferromagnetic stainless steel component. The procedure calls for an NDE method to detect fine surface-breaking cracks. Which of the following methods would be most appropriate and effective for this specific scenario?
- Magnetic Particle Testing (MT)
- Dye Penetrant Testing (PT) (Correct answer)
- Visual Testing (VT) with 5x magnification
- Radiographic Testing (RT)
Correct answer: Dye Penetrant Testing (PT)
Dye Penetrant Testing (PT) is a highly effective method for detecting surface-breaking defects like fine cracks and porosity in non-ferromagnetic materials. Magnetic Particle Testing (MT) is not suitable because the material is non-ferromagnetic. While VT is always performed, PT is more sensitive to very fine cracks. RT is primarily used for detecting internal, volumetric defects, not fine surface cracks.
Question 3: On a welding symbol, where is the information specifying the length and number of NDE examinations to be performed typically placed?
- To the left of the weld symbol
- Above the reference line
- In the tail of the reference line (Correct answer)
- Below the arrow
Correct answer: In the tail of the reference line
The tail of the welding symbol is used to convey supplementary information, which includes specifications for nondestructive examination such as the method to be used, the length to be examined, and the number of tests required.
Question 4: Which of the following NDE methods has no arrow side or other side significance when its symbol is placed on the reference line of a welding symbol?
- Visual Testing (VT)
- Magnetic Particle Testing (MT)
- Dye Penetrant Testing (PT)
- Radiographic Testing (RT) (Correct answer)
Correct answer: Radiographic Testing (RT)
Nondestructive examination methods that inspect the full volume of the weld, such as Radiographic Testing (RT) and Ultrasonic Testing (UT), do not have arrow side or other side significance. The examination covers the entire joint. Therefore, the symbol is placed directly on the reference line. Methods that inspect surfaces, like VT, MT, and PT, have arrow side/other side significance.
Question 5: A fabrication drawing for a carbon steel pressure vessel shows the NDE symbol 'MT' placed below the reference line with '(4)' written in the tail. What does this specify?
- Perform Magnetic Particle testing on the other side of the joint for a length of 4 inches.
- Perform four separate Magnetic Particle tests on the arrow side of the joint. (Correct answer)
- Perform Magnetic Particle testing on the arrow side of the joint using a 4-inch prod spacing.
- Perform four separate Ultrasonic Tests on the other side of the joint.
Correct answer: Perform four separate Magnetic Particle tests on the arrow side of the joint.
Placing the 'MT' symbol below the reference line indicates the test is for the 'arrow side.' Information in the tail of the symbol provides supplementary data. In this context, the number in parentheses specifies the number of examinations required.
Question 6: Which of the following is a significant limitation of Magnetic Particle Testing (MT)?
- It is only effective for detecting surface-breaking discontinuities.
- It can only be used on non-ferromagnetic materials.
- It is ineffective for detecting discontinuities that are not oriented favorably to the magnetic field. (Correct answer)
- It requires the use of ionizing radiation, posing a safety hazard.
Correct answer: It is ineffective for detecting discontinuities that are not oriented favorably to the magnetic field.
A key limitation of Magnetic Particle Testing is that the orientation of the discontinuity relative to the magnetic field is critical. The strongest indications occur when the discontinuity is perpendicular to the magnetic field lines. If it is parallel or nearly parallel, it may not be detected. MT is effective on ferromagnetic materials and can detect some sub-surface flaws, not just surface-breaking ones.
CWI NDE Methods and Symbols Questions and Answers
A welding blueprint has a symbol in the tail of the reference line that reads 'UT'.
This indicates that the weld requires which of the following?