Penetrant Testing Flashcards

How often should one measure the strength of UV light?

Answer: All of the above

The strength of UV light is crucial for effective fluorescent penetrant inspection (FPI) and must be regularly monitored. It should be measured at the start of an inspection cycle to ensure compliance, whenever a new bulb is installed to confirm proper function, and every 8 hours during continuous use to account for bulb degradation. Regular checks ensure consistent and reliable inspection results.

When the manufacturer initially sends the penetrant:

Answer: A sample of fresh solution should be collected and stored as a standard for future comparison

When a new batch of penetrant is received, it is essential to collect and store a sample as a reference standard. This 'control sample' allows for future comparison to monitor the performance of the in-use penetrant. By comparing the working penetrant to the fresh standard, any degradation or contamination can be detected, ensuring the penetrant maintains its required sensitivity.

Increasing the temperature will:

Answer: Raise the speed of evaporation of penetrants

Increasing the temperature of either the penetrant or the part being inspected will accelerate the evaporation rate of the penetrant's solvent. This can cause the penetrant to dry out too quickly, potentially reducing its ability to fully enter and dwell within discontinuities. Proper temperature control is therefore crucial for consistent and effective liquid penetrant inspection.

Most materials can be tested with LPI as long as the part's surface is

Answer: Is not extremely rough or porous

Liquid Penetrant Inspection (LPI) relies on the penetrant entering surface-breaking discontinuities. If the part's surface is extremely rough or porous, the penetrant can become trapped in the surface texture itself, leading to false indications or making it difficult to properly wash off excess penetrant. This can obscure actual defects or make interpretation unreliable, hence the need for a relatively smooth, non-porous surface.

Which kind of penetrant is less susceptible to cleaning fluid contamination?

Answer: Type II

Type II penetrants are visible penetrants, meaning they are detected by the naked eye under white light, unlike fluorescent (Type I) penetrants. Generally, visible penetrants are considered less sensitive to minor process variations and contamination compared to fluorescent penetrants, where even slight impurities can quench fluorescence and reduce detectability. This makes Type II less susceptible to certain types of cleaning fluid contamination that might degrade fluorescent properties.

When using a water suspendible developer, which developer form is used?

Answer: Form c

In Liquid Penetrant Inspection (LPI), developers are categorized into different forms based on their composition and application method. Form c specifically refers to a water-suspendible developer. These developers consist of insoluble powder particles that are suspended in water and then applied to the part to draw penetrant out of discontinuities.

Pollution of the penetration tool:

Answer: Will change the surface tension and contact angle

Contamination of the penetrant can significantly alter its critical physical properties. Impurities can change the penetrant's surface tension and contact angle, which are essential for its ability to properly wet the surface and penetrate into fine discontinuities. This degradation directly impacts the effectiveness and sensitivity of the liquid penetrant inspection process.

For water soluble developer, which kind of developer is used?

Answer: Form b

In Liquid Penetrant Inspection (LPI), developers are categorized into different forms. Form b specifically refers to a water-soluble developer. These developers consist of dry powder that completely dissolves in water to form a solution, which is then applied to the part to draw penetrant out of discontinuities.

While utilizing a fluorescent penetrant, the part's surface should have a white light intensity of:

Answer: A maximum of 2 foot-candles

When using fluorescent penetrants, the inspection area must be kept dark to ensure that fluorescent indications are clearly visible under UV light. A maximum white light intensity of 2 foot-candles (or 20 lux) is typically specified. This low level of ambient white light prevents interference with the detection of faint fluorescent indications, ensuring optimal sensitivity.

The water-washable penetrant's water content:

Answer: Must be checked regularly

Water-washable penetrants contain an emulsifier that allows them to be rinsed off with water. However, if the water content within the penetrant itself becomes too high, for example, due to carryover from washing or high humidity, it can reduce the penetrant's effectiveness and sensitivity. Therefore, regular checks of the water content are necessary to maintain consistent performance.

Water soluble developers are made up of the following chemical compounds:

Answer: Dissolved in water

Water-soluble developers are specifically formulated to dissolve completely in water, forming a uniform solution. When this solution is applied to a part, the water evaporates, leaving a thin, even layer of developer particles on the surface. These particles then effectively draw penetrant from any discontinuities, making them visible.