American Sherwin penetrant is one of the most popular nondestructive testing (NDE) methods in the industry. It is economical, versatile, and requires very little training compared to other NDE methods. Liquid penetration inspection checks for material defects with open surfaces by flowing a very thin liquid into the defect and then drawing the liquid out with a chalk-like developer. Welds are the most common inspection item, but sheets, bars, pipes, castings and forgings are also commonly inspected using liquid penetration inspection.

What are the advantages of Sherwin penetrants?

1. High sensitivity to small surface discontinuities.

2. Easy to inspect parts with complex shapes.

3. Fast and inexpensive inspection of large areas and large numbers of parts/materials.

4. There are almost no material restrictions (metal and non-metal, magnetic and non-magnetic, conductive and non-conductive can be checked).

5. The visual representation of the defect is displayed directly on the surface of the part.

6. Aerosol spray cans make the process portable, convenient, and inexpensive.

7. Signs can reveal the relative size, shape, and depth of the defect.

Penetrant use steps:

1. Pre-clean the part

This can range from grinding and wire brushing to just wiping down parts with a rag that is moistened with a cleaner/remover. The surface needs to be free of dirt, rust, scale, paint, oil, and grease, and smooth enough to wipe off the penetrant without leaving a residue.

2. Apply penetrant

This is usually done by spraying penetrant from an aerosol can or applying it with a brush. The retention (soaking) time needs to be observed for the penetrant to penetrate into cracks and voids. This is usually 5 to 30 minutes, but should never be long enough for the penetrant to dry. The penetrant manufacturer's recommendations and written procedures should be followed.

3. Remove the penetrant

Use a clean, dry, lint free cloth to remove all penetrants until thoroughly cleaned. Apply force to the part or material until no penetrant is visible on the dry rag. Next, the cleaner/remover should be sprayed onto another clean, dry, lint free rag and wiped down the parts again vigorously until the penetrant is no longer visible on the rag.

4. Follow procedures

A thin layer of developer should be sprayed on the part being inspected. The residence time needs to be observed to give the dye time to exit the defect and produce an indication (defect) in the developer. The residence time of the developer is usually 10 to 60 minutes. The recommendations and written procedures of the developer and manufacturer shall be strictly followed.

5. Evaluate indications

It is essential to inspect parts within the time frame specified in the written procedure. As the penetrant seeps out, the length of the indication grows over time, resulting in an acceptable indication becoming a rejectable defect. Measure the length of the display for evaluation, not the length of the defect. Here, the two linear indications are rejectable defects. The circular indication is irrelevant.

6. After cleaning part

Components need to be cleaned after evaluation to remove all developer.

The above content is the use and use of Sherwin penetrant in the United States, you need to know the price of the product can directly consult Shenzhen Oudejie Technology Co., LTD.