THE EFFECT OF PROCESSING VARIABLES ON HEAVY PLATES OF 12NI-5CR-3MO STEEL

Abstract : Because rolled heavy plates of 12Ni-5Cr-3Mo steel showed markedly lower notch toughness than light plates, a series of Laboratory and production studies was initiated to determine how the properties of heavy plates might be improved by varying processing procedures. The results of initial production studies indicated that midthickness properties of 4-in. thick plate produced by forging slabs to plate were superior to those of plate produced by rolling. However, the toughness at the surface and quarter-thickness of the forged plate was about the same as that of the rolled plate. Laboratory studies on the effect of forging temperature and degree of reduction indicated that (1) unless very heavy drafts (over 50% reduction) are possible, forging temperatures in the range 1800 to 2000 F are advisable, and (2) for all forging temperatures, heavy drafts results in forgings with better toughness than light drafts.