Quality issues after pipeline galvanizing
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What causes the zinc powder inside a pipe to flake off unevenly after galvanizing? How is it best to handle this?
The inner wall is losing powder; it seems that no electroplating was applied, and instead a layer of zinc powder was used as a substitute. During the galvanizing process, is an auxiliary anode used on the inner wall, and is the area of the anode sufficient?
For hot-dip galvanizing, material analysis, pickling quality analysis, zinc bath analysis, and so on are required. There are many such reasons. Go back, re-acid wash and re-galvanize.
The pipes are indeed hot-dip galvanized, but 1: the zinc melt was not poured out after they came out of the furnace, resulting in an accumulation of zinc melt. 2: The hot-dip galvanizing time is too short; this can be determined by measuring the thickness of the hot-dip galvanizing layer ； 3: Rust formation occurs when the zinc layer is too thin or the pickling process is not thorough enough ；
One possible reason for the under-plated areas is inadequate pickling
Flaking and peeling of the galvanized coating is a quality issue. Check whether the design requirements can be met; if not, this batch of materials cannot be used.
This should be hot-dip galvanizing, rather than electro-galvanizing