Characteristics of High-Strength Sheet Steel after Subsequent Heating

Abstract

The influence of controlled rolling and the parameters of subsequent technological heating on the processes of structure formation in high-strength sheet steels EH36 and X70 is investigated. It has been established that when redistributing a thick sheet into products, it is necessary to minimize the temperature-time parameters to prevent softening processes. Welding, as one of the sources of technological heating, leads to a change in the structure in the zone of thermal influence and uneven distribution of hardness over the cross section of welded joints, which reduces the uniform strength of the structure as a whole. Short-term heating (about 15 minutes) even to temperatures above Ac1 (760 ° C) and cooling in air in the weld zone do not lead to significant changes in structure and hardness, but the degree of uniformity of the welded sheets increases.