Galvanized pipe also known as galvanized steel pipe.

Hot dip galvanized pipe

Hot-dip galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe, after pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then fed. Hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life.

Folded cold galvanized pipe

Cold galvanizing is electrogalvanizing. The amount of galvanizing is very small, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. Regular galvanized pipe manufacturers, in order to ensure quality, most do not use electro-galvanizing (cold plating). Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper. In the future, cold galvanized pipes should not be used as water and gas pipes.

The main purpose

The galvanized pipe is often used to transport gas and heating. The galvanized pipe is used as a water pipe. After a few years of use, a large amount of rust is generated inside the pipe. The yellow water that flows out not only pollutes the sanitary ware, but also contains bacteria that grow on the unsmooth inner wall; the rust causes the heavy metal content in the water to be too high, which seriously endangers the health of the human body. In the 1960s and 1970s, developed countries in the world began to develop new types of pipes and banned galvanized pipes.

Process characteristics

Optimization of sulphate galvanizing

The biggest advantage of sulphate galvanizing is that the current efficiency is up to 100% and the deposition rate is fast, which is unmatched by other galvanizing processes. Because the plating crystal is not detailed enough, the dispersing ability and the deep plating ability are poor, so it is only suitable for electroplating of pipes and wires with simple geometric shapes. The sulphate electroplating zinc-iron alloy process optimizes the traditional sulphate galvanizing process, leaving only the main salt zinc sulphate, and the remaining components are discarded. In the composition of the new process, an appropriate amount of iron salt is added to form a zinc-iron alloy coating on the original single metal coating. The reorganization of the process not only carries forward the advantages of high current efficiency and fast deposition rate of the original process, but also greatly improves the dispersing ability and deep plating ability. In the past, complicated parts could not be plated, and now simple and complicated parts can be plated, and the protective performance 3 to 5 times better than single metal. The production practice proves that for continuous plating of wire and pipe, the plated grain is finer and brighter than the original, and the deposition rate is fast. The coating thickness meets the requirements within 2~3 minutes.

Conversion of sulphate galvanizing

The sulphate electroplated zinc-iron alloy retains only the main salt of zinc sulfate galvanized zinc sulfate, and the remaining components such as aluminum sulfate and alum (potassium aluminum sulfate) can be added to the bath to form insoluble hydroxide precipitates. Removal; for organic additives, add powdered activated carbon to remove. Tests show that aluminum sulfate and aluminum aluminum sulfate are difficult to remove completely at one time, which has an effect on the brightness of the coating, but it is not serious, and can be consumed with the belt. At this time, the brightness of the coating can be restored to the solution, which can be processed according to the new process. The component content is required to be added, that is, the conversion is completed.

Fast deposition rate and excellent protection

The current efficiency of sulphate electroplating zinc-iron alloy is up to 100%. The deposition rate is unmatched by any galvanizing process. The running speed of fine tube is 8~12 m/min, and the thickness of coating is 2m/min. This is difficult for continuous galvanizing. Achieved. The coating is bright and pleasing to the eye. According to the national standard GB/T10125 "artificial atmosphere test - salt spray test" method test, 72 h, the coating was intact and unchanged; 96 h, a small amount of white rust appeared on the surface of the coating.

Unique clean production

The galvanized pipe adopts the sulphate electroplating zinc-iron alloy process, in which the production line groove and the groove are pierced straight through without any carry-over or overflow of the solution. Each process in the production process consists of a circulation system. Each tank solution is an acid-base solution, a plating solution, a light-emitting and a passivation solution, etc., and only recycles and leaks to the outside of the system, and only 5 cleaning tanks are used in the production line. Reuse of regular discharge, especially in the production process without waste water after passivation.

Particularity of electroplating equipment

The electroplated copper wire of the galvanized pipe is the same as the continuous plating, but the plating equipment is different. The wire is designed with a slender strip shape and the groove is long and wide. When electroplating, the iron wire is pierced from the perforations and is in a shape of a straight line on the liquid surface to maintain the mutual spacing. The galvanized pipe is different from the wire, and its unique features, 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 circulating storage tank, forming a tank body with a narrow upper and a lower width and a trapezoidal shape, and a plating passage of a galvanized pipe plating operation is arranged in the plating tank. The bottom of the groove has two through holes communicating with the lower storage tank, and forms a plating liquid circulation multiplexing system with the submerged pump. Therefore, the galvanized pipe is the same as the wire plating, and the plated parts are dynamic, and unlike the wire plating, the plating solution of the electroplated galvanized pipe is also dynamic.