Question

Which of the following methods is not recommended for surface cleaning of a part for liquid penetrant examination?

a) Cleaning with organic solvents.
b) Blasting with shot or dull sand.
c) Cleaning with de-greasers.
d) Use of de-scaling solutions.
e) Ultrasonic cleaning methods.

Answer 1

Blasting with shot or dull sand is not recommended for cleaning surfaces prior to liquid penetrant examination because it can damage the surface and introduce defects.

Step-by-step explanation:

The method not recommended for surface cleaning of a part for liquid penetrant examination is blasting with shot or dull sand. This technique can potentially damage the surface and obscure or introduce defects, which could affect the results of the examination. Methods like cleaning with organic solvents, using de-greasers, and employing ultrasonic cleaning methods are generally gentle and effective at removing unwanted contaminants without harming the part's surface or altering its properties. The use of acidic or de-scaling solutions is typically reserved for the removal of inorganic deposits such as scale, and their appropriateness would depend on the specifics of the component and the type of residues present.