Widespread application of aluminized plate process
Release time: 2023-01-09
Aluminizing process is one of the effective methods for steel surface corrosion prevention. The aluminized steel has stable characteristics in oxidizing and corrosive media, will not damage the mechanical properties of raw materials, can greatly improve its service life, and can replace expensive heat-resistant steel and stainless steel in various environments. Therefore, it has attracted much attention in recent years. Through constant research and development, we have made technological progress.
With the continuous development of acid making technology, various new equipment, new processes and new materials are constantly put into use. In order to save costs, improve production efficiency and stability, it is particularly important to carry out anti-corrosion and anti-oxidation treatment on steel pipes for acid making equipment. The aluminizing process of steel pipes shall be strictly controlled. Put the preliminarily treated steel pipe material into the aluminum liquid at the set temperature, so that the molten iron reacts with the aluminum liquid, so that the aluminum diffuses to the steel pipe surface, forming a ferro aluminum alloy layer, thus significantly improving its oxidation resistance, corrosion resistance and other properties, and extending its service life.
The aluminized layer can effectively separate the humid air from the base metal and effectively prevent the electrochemical corrosion of the base metal. Foreign testing institutions have carried out exposure tests for a long time, and found that aluminized steel samples have no oxidation or rust on the surface after 20 years of air placement test. In the chemical industry, especially in the acid making equipment, the corrosion resistance of metals is highly required. After aluminizing treatment, a stable, dense, pore free and continuous aluminum alloy layer is formed on the metal surface by using the electrochemical characteristics of aluminum, which can effectively prevent the invasion of corrosion media, so as to achieve the purpose of corrosion prevention.
Aluminizing process is one of the effective methods for steel surface corrosion prevention. The steel treated by this process has stable characteristics in oxidizing and corrosive media, will not damage the mechanical properties of raw materials, can greatly improve its service life, and can replace expensive heat-resistant steel and stainless steel in various environments.
The aluminized plate process can be divided into immersion type and diffusion type according to different processes. The steel pipe material is directly taken out for cooling and curing after being dipped in high temperature aluminum liquid. Due to its rough surface formation and uneven thickness of aluminum coating, it is difficult to meet the parameter requirements, and gradually replaced by diffusion aluminizing process. Diffusion aluminizing process is to add thermal diffusion link before cooling. The process flow includes oil removal rust removal pre plating hot dip aluminizing correction cleaning inspection diffusion treatment correction cleaning and inspection. The diffusion aluminizing process adds the high temperature annealing stage on the basis of the immersion process. The aluminized material after hot dip is put into a high temperature furnace, heated to above 800 ° C for several hours, and then taken out for cooling. This high temperature process is a diffusion annealing process, which can melt and diffuse the aluminized layer on the steel surface. It also eliminates the unique dentate feature of pure aluminum layer and replaces it with aluminum iron alloy layer and solid molten crystal structure, so as to obtain the material characteristics of oxidation resistance, high temperature resistance and corrosion resistance.