The problem of missing plating of galvanized tubing is a quality problem that often occurs during the hot-dip galvanizing process. Solving this problem requires starting from many aspects. The following are ten tips that can help solve the problem of missing galvanized square and rectangular pipes:

1. Avoid excessive pickling of high-carbon steel: Excessive pickling will lose the surface protective layer of the steel, causing the galvanizing to be unstable and prone to missing plating. Therefore, it is necessary to control the pickling time and acid concentration to avoid excessive pickling.

2. Prevent the overheating and burning loss of the plating flux: The plating flux plays a role in enhancing the adhesion of the coating during the hot-dip galvanizing process, but excessive overheating will cause the plating flux to burn out, making the galvanizing effect poor. Therefore, it is necessary to control the temperature of the plating flux to avoid overheating.

3. High-concentration solvents can be applied in advance to areas that are prone to leakage of galvanized tubing: Before galvanizing, high-concentration solvents can be applied in advance to areas that are prone to leakage to improve the adhesion of the zinc liquid in this area and reduce leakage. plating risks.

4. The aluminum content in the zinc liquid should be controlled below 0.05%. It is recommended to use a master alloy with an aluminum content of 5-10%: excessive aluminum content in the zinc liquid will lead to a decrease in the solubility of zinc in the solution and prone to leakage plating. Therefore, it is necessary to control the aluminum content in the zinc liquid and use a suitable aluminum content master alloy.

5. Strengthen the pre-processing of hot-dip galvanizing of square and rectangular pipes: Pre-processing includes oil removal, rust removal, and other steps. The completion of these steps directly affects the quality of the coating. Therefore, pre-processing should be strengthened before hot-dip galvanizing to ensure that the surface of the workpiece is clean. 

6. After grinding off the surface of the flame-cutting area, completely remove the residual frosting of the square and rectangular pipe: there is residual frosting on the surface after flame-cutting, and this frosting will hurt the galvanizing effect. Therefore, the surface of the flame-cut area must be thoroughly polished and any remaining abrasive removed.

7. Keep the surface of the hot-dip galvanizing liquid at the entrance of the workpiece clean and prevent the enrichment of aluminum content: When the workpiece enters the galvanizing tank, ensure that the surface of the galvanizing liquid is clean to avoid the entry of impurities. At the same time, attention should be paid to preventing the enrichment of aluminum content and avoiding the problem of leakage in the coating.

8. Try to shorten the residence time of the process as much as possible: In the hot-dip galvanizing process, try to control the residence time of the process and reduce any delays in the galvanizing process to avoid the possibility of missed plating.

9. Thoroughly remove welding slag and welding slag spatter: After welding, welding slag, and welding slag spatter will remain on the surface of the square and rectangular pipe. These residues will affect the galvanizing effect. Therefore, welding slag and welding slag spatter must be thoroughly removed to ensure that the surface of the workpiece is clean.

10. Ensure the mass concentration and reasonable ratio of plating flux: The mass concentration and ratio of plating flux play a key role in the galvanizing effect. The concentration of plating flux must be accurately controlled and used in a reasonable ratio to ensure the quality of the coating.

Through the implementation of the above ten tips, the problem of missing plating of galvanized square and rectangular pipes can be effectively solved, the quality of galvanizing can be improved, and the service life and economic benefits of the product can be ensured.