Anticorrosion of galvanized steel pipe welding: after surface treatment, thermal spray zinc. If the site cannot be galvanized, you can follow the on-site anti-corrosion method: brush epoxy zinc-rich primer, epoxy mica iron intermediate paint, and polyurethane topcoat. The thickness refers to relevant standards.
Process characteristics of galvanized steel pipe
1. Optimization of sulfate galvanizing: The advantage of sulfate galvanizing is that the current efficiency is as high as 100% and the deposition rate is fast, which is unmatched by other galvanizing processes. Because the crystallization of the coating 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 galvanized iron alloy process optimizes the traditional sulfate galvanizing process, only retaining the main salt zinc sulfate, and discarding the rest of the components. An appropriate amount of iron salt is added to 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 single metal. Production practice has proved that for continuous electroplating of wires and pipes, the coating grains are finer and brighter than the original ones, and the deposition rate is fast. The coating thickness reaches the requirement within 2 to 3 minutes.
2. Transformation of sulfate galvanizing: only zinc sulfate, the main salt of sulfate galvanizing, is reserved for sulfate electro galvanized iron alloys, and the remaining components such as aluminum sulfate, alum (aluminum potassium sulfate), etc. can be added to the plating solution when processing Sodium makes it generate insoluble hydroxide to precipitate and remove; for organic additives, powdered activated carbon is added to absorb and remove. Tests have shown that aluminum sulfate and potassium aluminum sulfate are difficult to remove completely 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. Replenishment of component content is required to complete the conversion.
3. Fast deposition rate and excellent protection performance: the current efficiency of the sulfate electroplating galvanized iron alloy process is as high as 100%, and the fast deposition rate is unparalleled by any galvanizing process. The running speed of the fine tube is 8-12 m/min, and the coating thickness is an average of 2m/min, which is difficult to achieve by continuous galvanizing. The coating is bright and delicate. According to the national standard GB/T10125 “artificial atmosphere test-salt spray test” method, after 72 hours, the coating is intact and unchanged; after 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 electro-galvanized ferroalloy process, which means that the slots in the production line are perforated straight through without any carry-over or overflow of the solution. Each process in the production process is composed of a circulatory system. The solutions in each tank, namely acid and alkali solution, electroplating solution, light emitting and passivation solution, etc., are only recycled and not leaked or discharged outside the system. The production line only has 5 cleaning tanks, which are discharged regularly by recycling, especially for passivation. A production process that does not produce waste water after cleaning.
5. The particularity of the electroplating equipment: the electroplating copper wire electroplating of galvanized steel pipes is the same as that of continuous electroplating, but the plating equipment is different. The plating tank is designed for its slender strip shape, the tank body 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 them. However, galvanized steel pipes are different from iron wires and have their unique features. The groove equipment is more complicated. The tank body is composed of upper and lower parts, the upper part is the plating tank, and the lower part is the solution circulation storage tank, forming a trapezoidal tank body with a narrow upper part and a wider lower part. There are two through holes at the bottom of the tank to communicate with the lower storage tank and form a plating solution recycling system with the submerged pump. Therefore, the galvanized steel pipe is the same as the iron wire electroplating, and the plating parts are dynamic, and the difference from the iron wire electroplating is that the plating solution of the galvanized steel pipe is also dynamic.
Post time: Mar-29-2023