Due to the intensive cooling the surface temperature is drastically reduced resulting in the transformations of peripheral zone of the steel bar to a martensitic structure . At the end of the cooling period the heat existing in the steel bar core causes the surface temperature to increase up to a corresponding equalizing temperature and by this martensitic surface zone is tempered resulting in a heat treated structure with high strength and good toughness properties. After this Vandana controlled cooling the structure of steel Bar core is seen to be a fine grained ferrite – pearlite un like the coarse grains of normal cooled rebars. According to the known relation of hall – Fetch the core zone also exhibits higher strength and toughness properties than after standard cooling in the air.

Properties	CTD Bars	Vandana Tempcore
Weldability	Poor , hence welded joints avoided	Good and no loss of strength
Formability	Bend 3D to 5D, Re bend 5D to 8D	Excellent - Bend 1D Re- Bend 4D
Ductility & Fatigue	High	Very High ( suited for earthquake areas )
Corrossion Resistance	Heavy Sec. Scaling. During Twisting Poor	Better Corrosion Resistance
Workability	Loss strength due to temperature rise	Easy working due to the good ductility Hence pre-welded meshes can be made.
Fire Hazards		No loss in strength up to 500 deg. Cent.