Hot-dip galvanized steel pipes are made by reacting molten metal with an iron matrix to produce an alloy layer, thereby combining the matrix and the coating. Hot-dip galvanizing is to first pickle the steel pipe. To remove the iron oxide on the surface of the steel pipe, after pickling, it is cleaned in an ammonium chloride or zinc chloride aqueous solution or a mixed ammonium chloride and zinc chloride aqueous solution tank and then sent to the hot-dip coating tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life. The hot-dip galvanized steel pipe matrix undergoes complex physical and chemical reactions with the molten plating solution to form a corrosion-resistant and tightly structured zinc-iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix, so it has strong corrosion resistance.
Galvanized steel pipes are often mentioned. The iron pipes used for gas and heating are also galvanized steel pipes. Galvanized steel pipes are used as water pipes. After a few years of use, a large amount of rust will be generated in the pipes. The yellow water flowing out not only pollutes the sanitary ware but also contains bacteria that grow on the rough inner wall. The rust causes excessive heavy metal content in the water, which seriously endangers human health.
First, the production steps of hot-dip galvanized steel pipes
a. Round steel preparation;
b. Heating;
c. Hot rolling perforation;
d. Head cutting;
e. Pickling;
f. Grinding;
g. Lubrication;
h. Cold rolling processing;
i. Degreasing;
j. Solution heat treatment;
k. Straightening;
l. Pipe cutting;
m. Pickling;
n. Finished product inspection.
Second, the performance characteristics of hot-dip galvanized steel pipes
Corrosion resistance: The zinc coating can provide good cathodic protection. Even if the zinc layer is partially damaged, the electrochemical activity of zinc can continue to protect the steel pipe matrix.
Mechanical properties: The galvanized layer has good adhesion and hardness, and can resist a certain degree of mechanical wear.
Processing performance: The galvanized steel pipe is easy to cut, bend, expand, and other processing operations.
Appearance quality: The galvanized layer is uniform and smooth, which improves the appearance quality of the steel pipe.
Third, the production process of hot-dip galvanized steel pipe
1. Raw material preparation: Select high-quality carbon structural steel or alloy structural steel as raw materials.
2. Surface pretreatment:
Degreasing: Remove oil and dust on the surface of the steel pipe.
Pickling: Use acid to remove iron oxide and rust on the surface of the steel pipe.
Water washing: Rinse the surface of the steel pipe after pickling it with clean water.
Plating aid: Add plating aid to the zinc liquid to improve the adhesion of the galvanized layer.
3. Hot-dip galvanizing:
Molten zinc: Melt the zinc ingot into zinc liquid, and the temperature is generally controlled at 440℃~460℃.
Dipping: Immerse the pretreated steel pipe in zinc liquid for a certain period to make the zinc liquid evenly adhere to the surface of the steel pipe.
Cooling: Take the galvanized steel pipe out of the zinc liquid and cool it to room temperature.
4. Post-treatment:
Passivation: Passivation treatment is performed on the surface of the galvanized layer to improve the corrosion resistance of the galvanized layer.
Drying: Dry the passivated steel pipe for easy storage and transportation.
Fourth, the application field of hot-dip galvanized steel pipe
Construction industry: widely used in building structures, scaffolding, railings, transportation facilities, etc.
Chemical industry: used for pipelines and chemical equipment for conveying corrosive media.
Power industry: used for brackets and pipelines for power transmission and communication lines.
Agricultural field: used for greenhouses, irrigation systems, etc.
Post time: May-14-2025