Brief on TMT, HYSD & TOR Steel Bars

TMT, HYSD, TOR steel bars; the terms though confusing to the layman are the bread and butter for , and Each of the terms, stand for specific forms of steel that have a slight difference in their manufacturing process and resulting strengths. Following brief will help to understand them better.

TMT Steel Bars

TMT bars refer to thermo mechanically treated bars which have a ductile inner core as against an outer core that is quite hardened. They are named after the manufacturing process undergone by them which is called the Thermo Mechanical treatment. Hot rolled steel billets are passed through water which causes a hardening of their surface while retaining a soft inner core. This is because of the moderately warm temperature within which the inner core remains and this raises its ductility. The difference in the microstructure of the bar's cross-sectional area confers the bar with high amounts of strength. Overall tensile strength is also enhanced. As the TMT bars do not undergo a further deformation or twisting process they do not exhibit any defects or cracks on their surface.

HYSD Steel Bars

The term stands for High Yielding Strength Deformed Steel and the name is explanatory of its feature. The manufacturing process for this form too involves heat treatment as in the case of the TMT bars. However, further to the process of heat treatment the hot steel rods undergo an additional twisting process to lend them the required shape. They thus undergo both mechanical and thermal treatment.

TOR Steel Bars

Technically, TOR steel is known as CTD which refers to Cold Twisted Deformed steel. A type of HYSD steel, the steel bars in this case undergo cold twisting and deformation after the passage of the standard heat treatment process. The process of Deformation takes place after the process of elongation. Deformations are visible on the surface of the bar but the product is endowed with greater yield strength. This also gives the steel bars greater bonding capacity with concrete. Slippage in concrete is minimized due to the increased bonding capability. It is however, essential for the deformations to be spaced evenly along the bar's length.

Analysis of the Three Types

The iron content is more or less similar for the TMT and the TOR bars. Both of them are equally strong though the TMT bars, march a little ahead of the latter in the area of strength. TMT bars exhibit greater strength and better anti-corrosive features and therefore they are a preferred choice in large construction projects and especially those in the humid areas; for example along coastlines.

TOR bars are steel bars used for general purposes like construction of roads, buildings, bridges as they fulfill the standard strength norms. The major difference between the three types of steel bars lies in their process of manufacture. TMT bars undergo water quenching while the TOR and the HYSD bars undergo further cold twisting or heat rolling. You can choose any one of the three bars depending upon the requirements of your application.