TMT Bars


Thermo Mechanically Treated Rebars are the latest type of reinforcement bars currently used in the developed and developing world. They conform to the British Standard BS4449:2005. Low Carbon Prime Steel Billets are carefully selected for their designated chemistry (Carbon 0.14%-0.22%, Manganese 0.65%-0.9%, Silicon 0.15%-0.25%, Phosphorus 0.05% MAX, Sulphur 0.05% MAX). These billets are charged into a pusher-type reheating furnace which heats them to 1100°C and allowed to soak the heat to the core. They get their final shape after passing through various roughing and finishing stands. The final red-hot rebars are then passed through a cold water-jacket which cools the outer surface making it hard (martensite surface) whereas the core still remains at a higher temperature. These quenched bars are cooled and tempered on the cooling bed. The final result is a hard martensite annular ring on the outer most surface and a soft tempered perlite core which is a tough enough to absorb shock. This material has a high yield strength of 500 MPa and above with an elongation above 14%. Their main application is in construction of dams, bridges, high-rise buildings, mega structures, etc. In construction, these need to be pre-cut and bent as per the engineer’s specifications and drawings in order to avoid the complications and additional workload on site. Tononoka Rolling Mills Ltd can cut and supply special length bars as per the customer’s requirements with a cutting tolerance of ± 50mm.