DIFFERENCE BETWEEN TMT, HYSD AND TOR STEEL BARS?


TMT : TMT stands for Thermo Mechanically Treated  bars. They are high-strength reinforcement bars having a hardened outer core and a soft inner core. They are manufactured under a process called Thermo Mechanical Treatment.They are manufactured by passing hot rolled steel billets through water, which hardens the surface and increases its tensile strength while the inner core stays at a comparatively warmer temperature and hence, the core becomes more ductile. This variation in the microstructure of the cross-section of the bar provides huge strength to the bar. Since there are no twisting or deformation processes employed in this method, TMT bars have no surface cracks or other defects as well.

HYSD : HYSD stands for High Yielding Strength Deformed Steel; and is also their main characteristic. HYSD steel also undergoes heat treatment similar to TMT bars, but the subsequent processes are different. In this type of steel, after undergoing the heat treatment process, the hot steel rods are either heat rolled or cold twisted for shaping, thus making them both thermally and mechanically treated.

TOR : TOR has become synonymous with CTD, which stands for Cold Twisted Deformed steel. It is a form of HYSD steel, where the steel bars, after undergoing the mandatory heat treatment process, are cold twisted and deformed. These deformations are present on the surface and are done after an elongation process, which imparts higher yield strength to steel and the surface deformations impart higher bondage with concrete. Because of the deformations, these bars minimize slippage in concrete and increases the bond between the two materials. Deformed bars have a higher tensile strength than that of MS steel bars and the deformations should be uniformly spaced along the length of the bar.

Both TOR and TMT bars have almost comparable iron content, so both of them exhibit high strength, albeit TMT bars are significantly stronger. Also, due to the superiority in the strength of TMT bars and also because of its higher corrosive resistance, TMT bars are better suited for use in large concrete structures and concrete structures built on the coastlines where high humidity is a major issue. On the flip side of the coin, TOR bars are general-purpose steel bars used in buildings, roads, and bridges as they surpass the minimum strength requirements.


Here are the reasons that why TMT bars are better than HYSD bars.

1. TMT bars has a much ductility and it shows more % elongation than that HYSD bars display.
2. TMT bars are easy to bend in shape and make any thing which we desire due to its ductile nature than HYSD steel.
3. TMT bars has less residue stresses and more tensile strength than HYSD bars.
4. TMT bars don't has surface flaw compare to HYSD bars because it does not required .
5. TMT stell is less hard compare to HYSD and Its weight is less compare to HYSD steel.
6. TMT bars has more corrosion resistance property than HYSD bars.
7. TMT bars are earthquake resistance due to its high tensile strength and flexibility.
8. TMT bars are heat resistance. It can bear higher heat nearby 400 to 600 Degree Celsius.

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