Hot dip galvanizing
1. Hot dip galvanizing – protect the steel
2. How is the hot-dip galvanizing process?
3. Hot dip galvanizing – about electroplating and historical curiosities
4. Formation of the zinc coating
5. What conditions do we have to meet to carry out a proper and safe hot-dip galvanizing process?
Hot dip galvanizing - protect the steel
Many of us have probably heard about the slogan “galvanizing”. We more or less know what this process is about, as a result of participating in compulsory chemistry lessons at school. Zinc (Zn) is an element also associated with the cosmetics industry and the food industry. Zinc needs our skin, hair and nails. It also plays a significant role in our endocrine, digestive and nervous systems. Therefore, many dietary supplements contain this element. If we notice the effects of its deficiency, it is worth increasing its supply by eating eggs, red meat, cheese or seeds. Sometimes this is not enough and many people – especially women – take zinc supplements, usually for the sake of beauty. Hot dip galvanizing – protect the steel. This is, in a nutshell, the slogan describing the galvanizing process.
The above comments are, of course, only an introduction to what this article will deal with. We use zinc because of its binding and strengthening properties in metallurgy, in a process called “galvanizing”. It consists in skilful and specialist application of a permanent zinc layer on steel. Hot dip galvanizing – protect the steel. This is, in a nutshell, the slogan describing the galvanizing process.
How is the hot-dip galvanizing process?
We have already mentioned what galvanizing is in the first part of the statement. In the galvanizing process, we obtain a coating on both the outside and inside of the galvanized material. The electrochemical system between steel and zinc makes the resulting alloy of steel and zinc strong. By galvanizing steel surfaces, we have composite, impermeable and durable bonds between zinc and steel. The last statement sounds probably quite trivial and straightforward, but it helps to illustrate the final effect of the process in question to laymen.
Hot dip galvanizing - about electroplating and historical curiosities
The term “electroplating” itself is a broad concept, as it defines the coating of metal with other metals: chromium, nickel, copper, gold, cadmium, tin, or the zinc described in this article.
The turning point in the history of galvanizing was 1741. Then the French chemist Melouin proved during his research that the zinc coating is able to protect steel against corrosion. A hundred years later, the French scientist Sorel also made use of this discovery. He invented hot-dip galvanizing and was the first to use the slogan “electroplating”. So what does the above slogan mean? It is the process of creating an electrical voltage that protects the steel surface from rust. Iron and zinc, when in contact with each other, generate a protective current. The zinc coating is impermeable and even if it cracks somewhere over time, it will corrode first instead of the protected steel.
Galvanizing on a mass scale was first popularized by Tadeusz Sendzimir at the end of the 19th century. He proved that the process is economical and produces the desired results. Interestingly, the first production line of the galvanizing process was built in 1933 near Katowice. At that time, low carbonate sheets were galvanized.
Formation of the zinc coating
On the surface, hot dip galvanizing is easy and does its job well, however the very metallurgy of applying the zinc layer is quite complex. The layer itself is the result of a chemical reaction between iron and zinc, i.e. Stop. Liquid zinc can only be applied to steel that is well cleaned of rust and grease.
It is worth noting that the obtained coating is extremely durable and resistant to both mechanical falls and corrosion. This is because steel is relatively softer than the zinc coating. Nay. At the atomic level, the zinc layer is almost ‘welded’ to the steel, so the end product is durable.
What conditions do we have to meet to carry out a proper and safe hot-dip galvanizing process?
If we want to perform metal galvanizing works well and safely, we must remember the following tips:
- the rooms in which we are preparing the “galvanic bath” should be well ventilated;
- galvanizing may take place in contact with water at a temperature of 60 ° C;
- confronting zinc with other metals, excluding total immersion;
- at high temperatures (up to 200 ° C) during permanent exposure, and temporary up to 275 ° C;
Galvanizing, however, cannot be carried out in extreme alkaline solutions and in acids. Interestingly, we can successfully paint a galvanized coating if its color does not suit us.
