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Galvanized Steel Surface Defect Inspection Points

We see more hot dip galvanized steel craft on the market now, hot dip galvanized steel surfaces because of improper operation of the formation of surface defects, the need for strict process to produce better products.

If the defect is due to the hot-dip galvanizing equipment dysfunctional or poor control caused by defects, such defects can all be excluded. In general, there are several such common pitfalls:
1. Galvanized zinc particles appearing on the surface, that is, those rough small particles is not polished, and more than such small particles affect the appearance, but also affect the use. Reasons for the formation of such particles is because the bottom is too much dross galvanizing machine agitated float adhered galvanized sheet surface temperature is too high there is because the production of such bottom slag floats, in addition, the zinc solution contains excess aluminum, zinc and aluminum that has a good affinity, thus together, attached to the galvanized sheet surface. Elimination of zinc particles need only remedy that can be processed, for example, often deal with bottom slag, keeping cleaning of galvanized environment; galvanizing bath temperature is not too high, kept at 440 ℃ ~ 450 ℃ is appropriate; the content of aluminum in liquid zinc not too high, remained at around 0.1% is appropriate, Also note that stock too long will increase the oxidation, etc. in short, as long as the strict production of zinc particles, or can be eliminated.

2. Galvanized steel surface to form a thick edge, which means that the edge than in the middle part of the thick layer of zinc, it becomes a thick edge defects, is not conducive to strip coiling. Thick edge thick edge is divided into high-speed and low-speed webbing, causes thick edge of the air knife because galvanized angle adjustments caused by poor air blowing, and produce the formation of turbulence, and appropriately adjust the intensity of the air knife can be excluded this defect.

3. If an air knife gap clogging will form an air knife marks, require a special cleaning tool to clean up.

4. The gray zinc coating is the result of which mixed with iron and zinc alloy caused.

In addition, there are some surface defects, such as air knife scratches, zinc projections, shell-shaped surface, rib defects, etc., which requires the manufacturers in the production process strict operating procedures, strict process to produce better products.


Post time: Jun-06-2023