The billets/ingots are heated in a computer controlled reheating furnace and rolled through a sequence of rolling mill stands which produces TMT bars of uniform diameter and length. Next, the bars are subject to heat treatment in three stages:
of “Quenching” begins when the hot rolled bar leaves the final mill stand and is rapidly quenched by special water spray system. This converts the surface layer of the bar to the hardened structure called ‘Martensite' while the core remains austenitic.
of “Self Tempering” begins when the bar leaves the quenching box with a temperature gradient through its cross section, with the temperature of the core being higher than that of the surface. In this stage hear flows from the core to the surface called ‘Tempered Martensite'. The core is still austenitic.
of “Atmosphere Cooling” is on the cooling bed, where the austenitic core is transformed to a ductile ferrite core.
Thus, the grain structure consists of a combination of tough outer layer of tempered martensite and a ductile core ferrite – pearlite. This is what gives BALMUKUND – TMT its unique package of properties – an excellent combination of strength and ductility.
Every TMT bar that we produce passes through a series of rigorous tests and checks, to verify its structural integrity and metallurgical properties. The result: We not only meet ISI standards – we exceed them.