Novel process to refine grain size of NiCrMoV steel

The present study focuses on the grain refining of NiCrMoV steel. All the samples were austenitised at 1230 degrees C for 10 h, followed by holding at 350 degrees C for 20 h and then experienced different heat treatment processes to refine the grain. It is proved that the isothermal treatment newly proposed in the present paper is much more effective than the conventional normalising process due to the formation of pearlite, which can cut off the structural heredity between parent austenite and martensitic or ferritic product in NiCrMoV steel.