DEVELOPEMENT OF IMPACT RESISTANT MICRO ALLOYED DUAL PHASE STEEL

Abstract

In the present investigation a-micro alloyed low carbon steel having C = 0.1%, Si 0.12%, Mn = 0.9%, S & P = 0.03% and Nb = 0.02% has been taken for developing dual phase steel and for determination of its mechanical properties. First the specimen is lathed with specified dimension. Then it is given inter-critical heat treatment at 740,760 and 780 degree centigrade for 10,15,20 and 25 minutes followed by water quenching. Then it is given tempering operation at 350 degree centigrade for 10 minutes. Its impact value, volume fraction of ferrite & martensite has been studied. It was observed that as inter-critical temperature increased in the sequence 740,760 & 780 degree centigrade, the impact value of the DPS is increasing up to a limit and then it decreases depending upon the soaking time. Increasing the soaking time at different inter-critical temperature, the impact value of the tempered DPS increases up to some extent and then it start decreasing.