Some regularities of the structure formation in the process of high-frequency pulsed hardening of steels

摘要

Some regularities of the structure formation in the process of high-frequency pulsed hardening of steels are studied by the methods of metallography, microhardness testing, X-ray analysis, and calorimetry. The maximum hardness is attained at a depth of 0.1-03 mm from the surface. A sharp boundary separates the hardened zone from the original matrix. The transition zone is 25-30μm wide. The specific features of the effect of a single pulse and a pulse packet on a specimen moving under the induction heater are considered. The effect of a secondary pulse on the structure formed due to the primary pulse is studied. The resulting zone of a considerable loss of strength is 0.2-0.3 mm wide. An increase in the sulphur content of steels enhances the formation of microcracks when using the method of hardening under consideration. The regularities found must be taken into account when developing production methods.