SOBOTOVÁ Jana České vysoké učení technické v Praze

Spoluautoři CEJP Jiří, JURČI Petr, SALABOVÁ Petra, PRIKNER Otakar

Three types of ledeburitic cold work steels were austenitized at 1025°C, nitrogen gas quenched and double tempered. Sub-zero period, made at different temperatures and dwell times, was also inserted between quenching and tempering. For the research was used steel Sverker 21 made by conventional way and two P/M steels (Vanadis 4 Extra and Vanadis 6). The microstructure, mechanical properties and surface resistance to cyclic impact load have been investigated as a function of parameters of heat treatment. There were used metallographic and rtg analysis, hardness measurement, three point bending test and impact test for the evaluation effect of sub-zero processing to observed materials. Analysis of impact craters was made by laser confocal microscopy and SEM. The results proved small differences in behaviour of observed material, which can, under specific conditions, be determinative for lifetime period of tools.