With the ever-increasing demand of Steel for the visionary development around the globe, this reliable metal has been undergoing constant up-gradations and newer technologies and processes are being used for its manufacturing. With 1500 types of high-grade Steel available around the globe, there is immense growth seen to fulfill the different requirements Steel can cater to for development and infrastructure for the modern world.
Steel grading is one of the main characteristics used for selection of Steel for the different purposes. These grading systems are developed by National and International Standard organizations to ensure standard categorization and aid selection of Steel for their purpose.
Grading of Steel is very specific—based on factors like; chemical compositions, physical properties, heat treatments, fabrication processes, and forms:
The physical properties of a Steel product are a major factor that contribute to their grading parameter. The primary characteristics that determine the physical or mechanical properties of steel are; yield stress, tensile strength, and elongation of the final product. The value for these three factors determine the grade of steel and the users will select the grade that best suit their purpose.
Steel products are manufactured with a variety of chemical properties to meet the different application requirements. The grading systems are used to distinguish between these types, basis on these chemical properties. The contribution of the alloying elements play a critical role in determining the final chemical characteristics of a product. The percentage of Carbon, phosphorus, sulphur, manganese used in the composition of steel are critical in determining the grade of Steel as each of these elements cater to different applications.
A lot of time we undermine the effect the process can have on the final chemical and physical properties of a Steel product. The processes that are undertaken to produce the different types of steel are instrumental in determining the quality and grade of steel manufactured. Different types of processes will have different types of reactions, Hot-forming steel rods enhances their malleability and ductility while cold-rolling will make the steel become brittle. The type of process, the temperatures and timelines, the cycle of processes are crucial to decide the final grade of steel.
Application of Steel:
The main purpose of producing these different types of Steel with different chemical composition, physical properties and also the diverse range of processes is to cater to the array of applications. For the TMT Steel category, the four main grades of steel available in India are; Fe 415, Fe 500, Fe 550 and Fe 600 where the number determines the yield strength of the Steel product.
Fe 415 is used in corrosion and earthquake prone zones,
Fe 500 is used in the construction of bridges and buildings,
Fe 550 is designated for use in coastal areas, and
Fe600 is used for large RCC constructions for its high tensile strength.