RHL GOLD TMT bars are produced using the latest German technology and quenching process in a ‘State-of-the-Art’ automatic rolling mill where TMT bars are hot rolled from tested raw material of required chemical specification in a series of electronically controlled finishing stands and online PLC controlled thermo mechanical treatment in 3 successive stages as under:
The hot rolled bar coming out of the finishing rolling mill stand is passed through a quenching box where it is rapidly quenched using high pressure special water spray system. The surface of the bar gets hardened to the depth optimized for each section through formation of Martensitic rim while the core remains hot and Austenitic by this process in the quenching box.
The bar coming out of the quenching box thus has a hot core compared to the surface which is cooler compared to the core allowing the heat to flow from the core to the surface causing tempering of the outer martensitic layer of the bar into a structure called “Tempered Martensitic” The core still remains austenitic at this stage of the process.
The bar is then finished on a ‘State-of-the-Art’ Automatic rake type Cooling Bed where atmosphetic cooling of each bar takes place resulting in the transformation of the hot Austenitic core of the bar into a Ferrite Pearlite structure. The resultant final structure of the Bar produced consists of a hard and strong outer layer (Tempered Martensitic) with a soft and ductile inner core (Ferrite Pearlite) structure. RHL Gold TMT bars so produced has unique combination of high strength and ductility.