When it comes to constructing a building structure, the right set of resources must be used for ensuring the overall life and the integrity of the building. The introduction of reinforcement in construction improved the overall life expectancy of the structure and made them strong enough to withstand the forces of nature. Steel is the primary component used as reinforcement because of its excellent tensile strength, recyclability and similar thermal coefficient of expansion to that of concrete.
The birth of TMT steel
With time, newer and better innovations for reinforcement variations were introduced. Some of them were Mild steel and the HYSD steel bars, but these were replaced due to demands for reinforced bars that offered better resistance to corrosion and one that offered flexibility and more strength. This lead to the innovation of Thermomechanically Treated (TMT) steel bars.
The Facts of TMT
The TMT steel reinforced bars are manufactured similar to regular reinforced steel bars, but undergoes an additional three-step process, which gives the reinforced bar its desired strength and ductility ratio. The processes are:
Quenching: This involves cooling the rebar by a series of water jets. This rapid cooling results in hardening of the outer martensite layer.
Self-Tempering: This stage involves the flow of heat from the soft and hot inner core towards the outer surface making it further harder. This forms the tempered martensite layer.
Annealing: In this stage, the inner core is cooled at normal temperature. The core after cooling becomes a ferrite-pearlite mixture and this results in the ductility of the TMT rebar.
Fe 415 is not the only available grade of reinforcement TMT steel rebars. The higher grades for the TMT reinforced bars are classified into Fe 415, Fe 500, Fe 550 and Fe 600. The numbers denote the yield strength of the reinforced bar, higher the numbers, higher the tensile strength.
The True grade:
The Fe 415 is the true TMT grade of reinforcement steel bars, as it has the optimum tensile strength and the right ductility ratio. As far as the tensile strength is needed for supporting the load of the structure, ductility is needed for effective workability of the reinforced steel bars. Because of this, Fe 415 is the recommended choice for building homes for a common man.