Observe the surface condition of hot-dip galvanized coating by naked eyes, including the presence of bubbles, pits, white rust, black spots and other defects, and whether the coating thickness is uniform. This is the simplest and most intuitive detection method, but not completely reliable, because some defects can only be found under a magnifying glass.
Hot-dip galvanizing inspection methods and what to look for
Author: Robby
I. Hot-dip galvanizing detection method
1. Observation method
Observe the surface condition of hot-dip galvanized coating by naked eyes, including the presence of bubbles, pits, white rust, black spots and other defects, and whether the coating thickness is uniform. This is the simplest and most intuitive detection method, but not completely reliable, because some defects can only be found under a magnifying glass.
2. Thickness gauge method
A coating thickness gauge is used to test the thickness of the coating to ensure that the coating meets the standard. Generally speaking, galvanized coatings should be 7μm or more, while hot-dip galvanized coatings should be 45μm or more. It is important to note that thickness measurements should avoid defective areas.
3. Chemical composition analysis
The chemical composition of the hot-dip galvanized coating is analyzed to determine whether its quality is qualified. Commonly used analytical methods include X-ray fluorescence spectrometry analysis, electron probe analysis and so on. This method is more complicated, requires professional training, and requires the use of specialized equipment for measurement.
4. Salt spray test method
Salt spray test is a kind of simulation test conducted under harsh environmental conditions to verify the quality of galvanized materials by observing their corrosion under salt spray environmental conditions. Commonly used salt spray test methods include NSS, CASS and so on.
II. Precautions
1. The thickness, composition and surface condition of the hot-dip galvanized coating should be checked in accordance with the relevant standards before testing, and the testing method should be determined.
2. When testing should ensure that the sample surface is dry and clean, to avoid dust, oil, fingerprints, etc. to affect the test results.
3. Detection methods and equipment should be calibrated and calibrated, and maintenance and maintenance before use, to ensure its precision and accuracy.
4. Various testing methods should be effectively combined to determine whether the quality of hot-dip galvanized coating is qualified.
5. Detection records should be detailed, accurate, and save for inspection.
In short, the detection of the quality of hot-dip galvanized coating is very critical, and must be carried out under standard testing conditions to ensure the reliability and qualification of its quality.