1. The penetrant with the highest sensitivity is the best penetrant I apply

The best penetrant for the application is the one that uses the least amount of money and time to find the right indication. Sometimes this means not using the highest sensitivity penetrant. While higher sensitivity penetrants do give an indication of very small discontinuities, if you only need to find moderate discontinuities, higher sensitivity penetrants may not give you the best inspection results, as you will see compared to the inspection.

To begin selecting penetrants, review all management specifications and work procedures to understand the required sensitivity level. Consider the surface finish and configuration of the part. High sensitivity fluorescent penetrants are suitable for smooth, highly machined surfaces. However, high sensitivity fluorescent penetrants may leave too much fluorescent background on the blank casting, making inspection difficult. For rough surfaces, fluorescent penetrants with lower sensitivity are a better choice.

2. Signs of penetration are discontinuities

A penetration indication is a visual result or response to a penetration test that must be interpreted to determine its relevance. Signs of infiltration must be evaluated by a qualified inspector to determine if they are irrelevant or relevant. There may be irrelevant signs on the part due to inherent surface roughness or joints. Fingerprints or fibers may also cause unrelated signs. Relevant signs are the result of discontinuities or interruptions in the physical structure of the object and are assessed against acceptance criteria. After evaluation, parts are accepted as is, reworked or discarded.

3. Water wash penetrant is water based

Some washable penetrants are water based. However, this is not always the case. The penetrant may be washable and water-free. Washable penetrants contain surfactants, whether water - or oil-based, that can be easily removed from the surface of the part by water rinsing.

4. Penetrants are only used for non-ferrous metals

Penetrants can be used to check ferrous and non-ferrous metals. Penetration inspection will reveal discontinuities on ferrous and non-ferrous metal surfaces. Penetration testing should not be performed on porous surfaces, as holes act as discontinuities to trap penetrant and prevent accurate inspection.

5. The penetrant will be able to penetrate the discontinuity of water

If the penetrant has been filled with water or other liquid, the penetrant cannot penetrate intermittently. Similarly, penetrants do not displace or penetrate paint, particles, oil or grease. This is one of the reasons why an important prerequisite for effective penetration inspection is to start with properly cleaned and dried parts.

6. Penetration testing requires storage tanks and testing tables

Penetration testing is easy to adapt to different environments and workplaces. Penetration inspection systems with fixed tanks and booths are common in production environments. However, for convenience and portability, both fluorescent and visible dye penetrants can be used in aerosol cans and kits.

7. Only penetrant is needed to perform penetration inspection

At a minimum, the penetrant and developer need to be washed for penetrant inspection. Solvent removal and post-emulsification penetration inspection require additional products such as cleaners/removers and emulsifiers.

8, penetration testing requires special lighting

Fluorescent penetrants do need to be checked in dark areas using UV lamps that meet specifications. Uv lamps can be mounted or hand-held for flexibility and portability. Visible dye penetrants only require sufficient white light for inspection, usually at least 100 feet of candlelight.

9. Penetration inspection should be the final inspection in the manufacturing process

Penetration inspection immediately after any manufacturing process known to cause discontinuity. This allows parts to be reworked or discarded early in the manufacturing process, saving time and costs. During part manufacturing, penetration checks may sometimes be performed multiple times. The location of each penetration inspection process should be optimized to locate discontinuities caused by manufacturing and reduce the amount of scrap or rework later in the manufacturing process.

10. Penetration testing can be carried out at any time during the manufacturing process

As discussed, it is important to perform penetration checks after manufacturing operations, which can lead to discontinuities on part surfaces. However, before performing mechanical operations that will smear metal surfaces, care must be taken to perform penetration checks. Machining operations such as shot peening, shot peening, or grinding may close surface discontinuities, which prevents subsequent penetration inspections from detecting these discontinuities.

Unless chemical etching can be used between these operations and penetration testing to reliably expose discontinuities, penetration checks should be performed prior to machining operations such as shot peening, shot peening, or grinding.

The above describes the questions that expose 10 common misconceptions about SHERWIN osmosis. In addition, Shenzhen Oudejie Technology specializes in the sale of new imported SHERWIN Sherwin penetrant, and promises to sell products are new imported original, while providing our customers with quotation, selection, product information and other services.