CN-117026130-B - Preparation method of hot dip galvanized steel

CN117026130BCN 117026130 BCN117026130 BCN 117026130BCN-117026130-B

Abstract

The application relates to the technical field of cold-rolled strip steel production, in particular to a preparation method of hot-dip galvanized steel. The method comprises the steps of annealing a cold hard plate, controlling annealing technological parameters, carrying out hot galvanizing on the annealed cold hard plate, controlling a furnace nose dew point in the hot galvanizing process to obtain first hot galvanized steel, carrying out surface straightening on the first hot galvanized steel, and controlling the technological parameters of the surface straightening to obtain the hot galvanized steel. The method has simple process control, solves the problem of poor uniformity of the thickness of the zinc layer on the surface of the strip steel produced by cold rolling galvanization, and provides guarantee for the product quality of the subsequent production line.

Inventors

ZHANG RENYUAN
YU HAIWEN
FU HAIFENG
HUANG SHIYAN
CUI JUNPENG
GUO ZHIQIANG
LI TAO
GUO LIANGYUAN
YANG XIAOLING

Assignees

北京首钢冷轧薄板有限公司

Dates

Publication Date: 20260512
Application Date: 20230805

Claims (2)

1. A method of preparing a hot dip galvanized steel, the method comprising: Annealing the cold hard plate, and controlling the annealing process parameters; carrying out hot galvanizing on the annealed cold hard plate, and controlling the furnace nose dew point in the hot galvanizing process to be less than or equal to minus 35 ℃ to obtain first hot galvanized steel; The first hot dip galvanized steel is subjected to surface straightening, the distance between a knife edge baffle and the first hot dip galvanized steel is controlled to be less than or equal to 5mm, the distance between an air knife and zinc liquid is 180-300mm, and the insertion amount of a zinc pot roller is 0-30mm, so that the hot dip galvanized steel is obtained; the annealing process parameters comprise annealing soaking section temperature, annealing slow cooling section temperature, air door opening degree of a fast cooling section and strip steel running speed, wherein the strip steel running speed is less than or equal to 90m/min, and the air door opening degree of the fast cooling section is 33-100%; the thickness of the strip steel is 1.2mm, 1.5mm or 1.8mm; the temperature of the annealing soaking section is 770-790 ℃ and/or the temperature of the annealing slow cooling section is 660-700 ℃.
2. The method of claim 1, wherein the cooling medium of the air knife is nitrogen.

Description

Preparation method of hot dip galvanized steel Technical Field The application relates to the technical field of cold-rolled strip steel production, in particular to a preparation method of hot-dip galvanized steel. Background The zinc layer uniformity has great influence on the quality of galvanized products, uneven zinc layers are easy to cause edge thickening, the difference of the zinc layer thickness of the cross section is too large, the waste of raw materials such as zinc ingots is caused, the production cost is improved, the adhesiveness of the zinc layers is also influenced, the service performance such as stamping resistance of the products is also influenced, and the use requirements of customers cannot be met. The galvanized unit produces products, side waves are easy to occur, the plate shape at the air knife cannot be guaranteed, shaking is serious, uniformity of zinc layers is poor, quality of the products is affected, and quality requirements of clients cannot be met. Therefore, there is a need to produce a hot dip galvanized steel having good uniformity of zinc layer thickness. Disclosure of Invention The application provides a preparation method of hot dip galvanized steel, which aims to solve the technical problem that the zinc layer thickness of the existing hot dip galvanized steel is uneven. In a first aspect, the present application provides a method for preparing hot dip galvanized steel, the method comprising: Annealing the cold hard plate, and controlling the annealing process parameters; carrying out hot galvanizing on the annealed cold hard plate, and controlling a furnace nose dew point in the hot galvanizing process to obtain first hot galvanized steel; and carrying out surface straightening on the first hot dip galvanized steel, and controlling the technological parameters of the surface straightening to obtain the hot dip galvanized steel. Optionally, the technological parameters of the flat surface comprise a cooling medium of the air knife, a distance between the baffle plate at the edge of the air knife and the first hot dip galvanized steel, a distance between the air knife and zinc liquid and the insertion amount of the zinc pot roller. Optionally, the cooling medium of the air knife is nitrogen. Optionally, the distance between the knife edge baffle and the first hot dip galvanized steel is less than or equal to 5mm, and/or the distance between the air knife and the zinc liquid is 180-300mm. Optionally, the insertion amount of the zinc pot roller is 0-30mm. Optionally, the dew point of the furnace nose is less than or equal to-35 ℃. Optionally, the annealing process parameters comprise annealing soaking section temperature, annealing slow cooling section temperature, air door opening degree of a fast cooling section and strip steel running speed. Optionally, the running speed of the strip steel is less than or equal to 90m/min. Optionally, the opening degree of the air door of the quick cooling section is 33-100%. Optionally, the temperature of the annealing soaking section is 770-790 ℃ and/or the temperature of the annealing slow cooling section is 660-700 ℃. Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages: according to the preparation method of the hot dip galvanized steel, provided by the embodiment of the application, the annealing process parameters, the furnace nose dew point and the process parameters of the flat steel plate surface are controlled, so that the uniformity of the galvanized zinc layer thickness is effectively controlled. The method has simple process control, solves the problem of poor uniformity of the thickness of the zinc layer on the surface of the strip steel produced by cold rolling galvanization, and provides guarantee for the product quality of the subsequent production line. Drawings The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application. In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort. FIG. 1 is a schematic flow chart of a method for preparing hot dip galvanized steel according to an embodiment of the application; fig. 2 shows the transverse zinc layer thickness of a hot dip galvanized steel according to the embodiment 1 of the application, wherein, 1-The thickness of a strip steel transverse zinc layer, 2-the maximum value of the thickness of the strip steel transverse zinc layer, 3-the average value of the thickness of the strip steel transverse zinc layer, 4-the minimum va