Process characteristics of galvanized steel pipe
1. Optimization of sulfate zinc plating
The advantages of sulfate galvanizing are that the current efficiency is as high as 100% and the deposition rate is fast, which is unmatched by other galvanizing processes. Because the coating crystallization is not fine enough, the dispersion ability and deep plating ability are poor, so it is only suitable for the electroplating of pipes and wires with simple geometric shapes. The sulfate electroplating zinc-iron alloy process optimizes the traditional sulfate galvanizing process, only the main salt zinc sulfate is retained, and the remaining components are discarded.
An appropriate amount of iron salt is added into the new process formula to make the original single metal coating form a zinc-iron alloy coating. The reorganization of the process not only carried forward the advantages of high current efficiency and fast deposition rate of the original process but also greatly improved the dispersion ability and deep plating ability. In the past, complex parts could not be plated, but now simple and complex parts can be plated, and the protective performance is 3 to 5 times higher than that of a single metal.
Production practice has proved that for continuous electroplating of wires and pipes, the coating grains are finer and brighter than the original, and the deposition rate is faster. The thickness of the plating layer meets the requirements within 2 to 3 minutes.
2. Conversion of sulfate zinc plating
Sulfate electroplating zinc-iron alloy only retains zinc sulfate, the main salt of sulfate zinc plating, and the remaining components such as aluminum sulfate, alum (potassium aluminum sulfate), etc. can be treated by adding sodium hydroxide to form insoluble hydroxide precipitates during bath treatment Removal; for organic additives, add powdered activated carbon to absorb and remove.
Tests have shown that aluminum sulfate and potassium aluminum sulfate are difficult to completely remove at one time, and have an impact on the brightness of the coating, but it is not serious and can be consumed along with it. At this time, the brightness of the coating can be restored to the solution and pass the treatment. It can be processed according to the new process. The content of ingredients needs to be supplemented to complete the conversion.
3. Fast deposition rate and excellent protection performance
The current efficiency of the sulfate electroplating zinc-iron alloy process is as high as 100%. The fast deposition rate is unmatched by any galvanizing process. The running speed of the fine tube is 8-12 m/min and the average coating thickness is 2m/min. This is difficult for continuous galvanizing. Reached.
The coating is bright and detailed and pleasing to the eye. According to the national standard GB/T10125 "Artificial Atmosphere Test-Salt Spray Test" method, 72 hours, the coating is intact and unchanged; 96 hours, a small amount of white rust appears on the surface of the coating.
4. Unique clean production
The galvanized steel pipe adopts the sulfate electroplating zinc-iron alloy process, which is that the production line groove and the groove are perforated and passed without any solution being brought out or overflowing. Each process in the production process is composed of a circulatory system.
Each tank solution, namely acid-base solution, electroplating solution, light emitting and passivation solution, etc., is only recycled and does not leak or discharge to the outside of the system. There are only 5 cleaning tanks in the production line, and the recycling is used for regular discharge, especially for passivation. No wastewater production process without cleaning afterward.
5. The particularity of electroplating equipment
The electroplated copper wire of galvanized steel pipe is the same as continuous electroplating, but the plating equipment is different. The plating tank designed for the iron wire with its slender strip features is long and wide but shallow. During electroplating, the iron wire passes through the hole and spreads out on the liquid surface in a straight line, keeping the distance between each other. The galvanized pipe is different from the iron wire. It has its unique features and the tank equipment is more complicated.
The tank body is composed of upper and lower parts. The upper part is a plating tank, and the lower part is a solution circulation storage tank, forming a trapezoid-like tank with a narrow upper and a wide bottom. The galvanized pipe is equipped with a galvanized pipe running channel in the plating tank. There are two through holes at the bottom of the tank communicating with the lower storage tank and forming a plating solution recycling system with the submerged pump.
Therefore, the galvanized steel pipe is the same as the iron wire electroplating, the plating parts are dynamic and different from the iron wire electroplating, the plating solution of the electrogalvazed pipe is also dynamic.