Fine grained steels are know for combination of higher strength and improved toughness. Fine grained steels are conventionally produced by micro alloying steels with Niobium, Vanadium, Titanium or Boron additions. However, like normal steels, Micro-alloyed steel also exhibited limitation of achieving toughness at the cost of strength & vice versa.  Alternate method is developed to achieve similar grain refinement through controlled Heat treatment. Heating rates for such treatments are higher than the conventional practices and are of the order of 250^OC / Sec. Improvements in mechanical properties by about 25% with 30% enhanced toughness. Grain size achieved is ASTM 8-9.

This paper describes the process control set to achieve fine grained structure for certain steels. Enhancement of mechanical properties alongwith higher toughness is compared with the same steel treated with conventional heat treatment.

 

Key words : Fine grained steels, enhanced mechanical properties.