Under thermo mechanical treatment, the steel bars are passed through a specially designed water-cooling system where they are kept till the outer surface of the bars becomes colder while the core remains hot. This creates a temperature gradient in the bars.
When the bars are taken out of the cooling system, the heat flows from the core to the outer surface, further tempering of the bars, which helps them attain higher yield strength. The resulting heat-treated structure imparts superior strength and toughness to the bars. The microstructure of the core is a very fine grained ferrite and pearlite. TMT bars are also known as “Quenched Wand Tempered Rebar (QTB)” because of the quenching and tempering processes involved in making the bars.
The production of quality TMT bar depends on three major factors – quality raw materials, a properly designed and automated mill, and a well-designed quenching and tempering technology. All rebar must be purchased based on the properties of yield strength, tensile strength and elongation values.
The bars come in different lengths, in sizes of 11 to 12 meters and can be customized to the required specifications. TMT bars that have uniform and concentrated hardened periphery and the softer core will have the desired tensile strengths coupled with high elongation as required in seismic zones. Depending on the size and grade, rebar with hardened periphery of about 15 to 30 per cent of the cross sectional area of the bar are ideal for civil constructions )constructions of houses, bridge, culverts, offices, etc.)
Our Thermo Mechanically Treated TMT steel bars are widely used in all types of construction purposes. They exhibit very high bend ability a also re-bend ability features due to lower carbon content and higher elongation with excellent yield and ductility characteristics, our TMT steel bars are ideally suited for application in earthquake zones.