1. Because there is fat on the outer tube wall of the base tube, the fat on the wall of the steel pipe will increase the appearance tension, and the pickling steps before galvanized cannot remove the surface oil. The basal tube is rusty, and sometimes the plating agent is not attached, and a protective salt mold is formed. In the high -temperature melting zinc tank, the steel pipe is oxidized quickly, so zinc liquid will not produce any chemical or physical reactions with the substrate. After the steel pipe is separated from the zinc liquid pool, under the impact of gravity, the zinc liquid will flow and uneven, so there will still be black oil ash in a thin zinc layer position.
2. The outer surface of the alloy base tube has been severely corroded. The steel pipe is not cleaned, and iron oxide still remains. Although the auxiliary plating can be adhered to it, when the base tube is immersed in the melted zinc solution, the zinc liquid cannot be directly exposed to the wire and no reaction will occur. After the steel pipe is separated from the zinc liquid pool, the exposed side is relatively clean, so the surface of the galvanized greenhouse tube will be a bit eroded.
3. The wall of the basal tube has thicker oil and difficult to remove stains, so it will inevitably leak plating, and it will be very inconvenient to process, because the steel pipe needs to be cleaned from beginning to end. The tube wall of the base tube has the same shape as the size of mung beans. When baking, the zinc liquid of the steel pipe pipe is closely attached to the surface of the steel pipe. Like rust steel pipes. All leaks are the same, but the leakage situation in this situation is relatively smaller and smaller, and the edges are relatively flat.
4. There are scars on the wall of the basal tube and rough appearance. Obviously, the stains will enter the scratch. It is difficult to remove such dirt before galvanizing the pickling and alkali washing steps. The leakage defect is presented with a long and detailed form. This leakage is very rare.
5. During the galvanized process, the temperature does not meet the requirements, and the galvanized greenhouse tube is prone to leakage.
