The test series should clarify the influence of the quenching
temperature on the microstructure and on the martensite formation as well as possible
defects. The examined material was 100Cr6.
Initial condition : hot rolled 16,00 mm , spheroidised
Heat treatment : laboratory furnace (volume 5 liter) ; soaking
of the samples in 5 minutes
Hardening : 860 and 1000° C , holding time 30 minutes ,
quenching in oil
By the quenching from temperatures high above the right quenching
temperature almost all carbides of the initial structure are going in solution
. Through this, it comes intensified too high amounts of retained austenite in
the microstructure. By excessive tensions in the microstructure, stress cracks,
going out from the surface, are frequently the consequence. Microcracks in the
first formed martensite needles also have to be observed at high temperatures.