Method for hot-dip galvanizing strip steels

Abstract

The invention discloses a method for hot-dip galvanizing strip steels, the method of the invention optimizes the traditional hot-dip galvanizing liquid, optimizes the orientation of coating crystal grains and obviously raises the scratch resistance, wear resistance and adhesiveness of a coating layer. The method employs a non-chrome environmentally-friendly passivating solution formula for satisfying the requirement of environmental protection. Compared with the prior art, the hot-dip galvanized strip steels have good welding performance and coating performance of the traditional alloying hot-dip galvanizing strip steels, and have excellent corrosion resistant performance, black resistance performance, conductivity and environmental protection performance.

Description

technical field [0001] The invention relates to the field of strip steel surface coating, in particular to a strip steel hot-dip galvanizing method. Background technique [0002] The production method of hot-dip galvanized steel strip has experienced the evolution process of the early Sendzimir process, the improved Sendzimir process and the United States steel process. Affected by the production process, it is difficult for the products produced by the improved Sendzimir process to meet the requirements of alloyed strip regardless of their surface quality (including spangle structure) or the range of steel types that can be produced; in addition, the post-treatment of the Sendzimir process The production of environmentally friendly alloyed hot-dip galvanized steel strips is generally not considered in the design of the section, so the equipment configuration of the post-processing section cannot meet the needs of producing environmentally friendly alloyed hot-dip galvanized...

AI Technical Summary

Problems solved by technology

In order to meet these characteristics, some domestic iron and steel enterprises have developed alloyed hot-dip galvanized sheets. The production method of alloyed hot-dip galvanized strip steel is to heat the hot-dip galvanized strip steel in an alloying furnace after galvanizing at about 500°C. , the alloying reaction between the surface pure zinc layer and the steel substrate is formed to form an alloyed coating composed of Fe-Zn compounds, but the corrosion resistance, blackening resistance and electrical conductivity of the alloyed hot-dip galvanized strip steel are poor , and the coating is prone to powdering and peeling during stamping deformation, and the galvanized layer is easily damaged, which not only deteriorates the corrosion resistance, but also easily causes surface defects, affecting the appearance after coating

The Chinese patent application with application number 02801081.7 introduces a production method of alloyed hot-dip galvanized strip steel, but the strip steel produced by it has disadvantages such as poor corrosion resistance, blackening resistance, and lubricating performance. On January 27, 2002, the Directive on Waste Electrical and Electronic Equipment (WEEE-2002 / 96 / EC) and the Directive on Prohibiting the Use of Certain Hazardous Substances in Large Electrical and Electronic Equipment (RoHS-2002 / 95 / EC) were officially announced. The directive requires that the sale of electronic and electrical equipment containing hazardous substances such as Hg, Cd, Cr6+, Pb, PPBs, and PBDEs will be prohibited in the EU market from July 1, 2006

However, general zinc-iron alloy products usually use non-passivation or hexavalent chromium passivation, which seriously affects their performance and environmental protection requirements.