Energetica India Magazine - September 2022

Hot Dipped Galvanized Vs Pre-Galvanized: Developer’s Perspective 72 energetica INDIA- September_2022 1. Preface Steel is the most common material used in almost all products i.e., from households to Industrial application. Significant part of the economy is steel sector based; however, steel have one large disadvantage – its high corrosion rate. Hence protection of steel structures and components is of great economic importance. In Indian subcontinents, the rate of corrosion is quite high con - sidering hot and humid environmental conditions. Zinc is mostly used as an anti-corrosion agent and be - ing used from very early ages i.e., from 200BC to obtain brass which is alloy of copper and zinc. It has inherent natural capacity to protect steel against corrosion. In 1742, a chemist known as Melouin found that a zinc coating could be applied to iron by dipping it into molten zinc which indeed laid the foundation for gal - vanizing. In 1780, an Italian physicist, Luigi Galvani, observed that the contact between two dissimilar met - als resulted in the flow of an electrical current. He worked in field of galvanization and on the name of this physicist, the process is named as Galvanization. Subsequently in year 1836, a French civil engineer, in - ventor cum chemist, named as Stanislas Sorel patented a method of galvanization by cleaning steel and then coating it with zinc by dipping it into molten zinc. This was the beginning of modern hot-dip galvanizing As India is accelerating towards its goal of 300 GW solar capacity by 2030 from 58 GW at present, do we need to change our engineering designs for making a long-term & sustainable solution or should we continue focusing on the designs developed by Western countries, for totally different environmental conditions. Shankar Sengupta Head – Energy Engineering Group, Adani Corporate House, Ahmedabad POWER SECTOR cross-section of the galvanized steel coating, showing a typical microstructure comprised of three alloy layers and a layer of pure metallic zinc 2. Benefits of Galvanization Hot-dip galvanizing has been in use over 100 years to protect steel corrosion worldwide; however, over the decades, many new mate - rial and process has been evolved. Comparing all the use of hot- dipped galvanization remained most trusted based on their superb performance and till date experience as user. In the HDG process, the base material is getting three level pro - tection. i. Zinc Layer Barrier Protection which protects steel by insulating direct contact with air and moisture. ii. Cathodic Protection where in zinc acts as anode and sacrifices itself protecting the steel from corrosion iii. Zinc Patine where in zinc oxidizes and builds a protective layer over steel