Single-side galvanizing method for producing hot-dip galvanized steel pipe

Abstract

The invention relates to a single-side galvanizing method for producing a hot-dip galvanized steel pipe. The single-side galvanizing method comprises the following steps of: 1) workpiece pretreatment; 2) acid washing; 3) water washing; 4) plating aid dipping; 5) neutralization of plating aid on the inner wall of the steel pipe; 6) drying and preheating; 7) hot-dip galvanization; 8) passivation; 9) cooling; and 10) inspection and packaging. By destroying a plating aid layer on the inner wall of the steel pipe and accurately controlling process parameters such as galvanizing time, the single-side galvanizing method for producing the hot-dip galvanized steel pipe has the advantages that the single-size galvanizing goal of fully galvanizing the outer wall and not galvanizing the inner wall at all is achieved, the single-side hot-dip galvanized steel pipe produced by adopting the method can be closely combined with a plastic pipe, the plastic is not apt to fall, the service life of a compound pipe is guaranteed, the product quality is greatly improved and the market promotion prospect is wide.

Description

technical field [0001] The invention belongs to the field of processing plastic-lined composite steel pipes, in particular to a single-sided galvanizing method for hot-dip galvanized steel pipes. Background technique [0002] The plastic-lined composite steel pipe is composed of a galvanized steel pipe base material and a layer of plastic pipe attached to the inner surface. Compared with other metal pipes, plastic pipes and composite pipes, the plastic-lined composite steel pipe combines the characteristics of various pipes, that is, it has the advantages of high strength, high elongation, good low temperature brittleness, and small expansion coefficient of steel pipes. Plastic pipes have the advantages of corrosion resistance, wear resistance, and small fluid resistance. They are a new type of water supply and drainage, anti-corrosion green pipes, and are more and more widely used in various domestic industries. [0003] The biggest problem existing in the existing plastic...

AI Technical Summary

Problems solved by technology

[0003] The biggest problem existing in the existing plastic-lined composite steel pipe is that the bonding effect between the galvanized steel pipe and the inner plastic pipe is not good. The inner and outer walls of the steel pipe after zinc are attached with a zinc layer. When the plastic pipe is bonded to the inner wall of the steel pipe at high temperature in the later stage, the bonding strength between the zinc layer on the inner wall and the plastic pipe is weak, especially at about 70 degrees, it will automatically fall off. , affecting the strength and performance of the product

[0005] It can be seen that in the above methods, the zinc layer is not completely removed, and there are residual problems on the inner wall of the galvanized pipe, which seriously affects the quality of the plastic-lined composite steel pipe.