Insufficient austenitization at the quenching - 1.2242
Initial condition at this heat treatment was a spheroidised structure. After the quenching and tempering the sample showed different microstructure conditions. The microstructure was quenched and tempered only half. The remaining half of the microstructure was still in the annealing condition. Cause was an insufficient austenitization of the sample. Either the austenitizing temperature was too low or/and the holding time on austenitizing temperature was considerably too short. Through this the sample wasn't completely austenitic at the time of the quenching. Only the austenite could transform into martensite at the quenching. By the following tempering the martensite has disintegrated. A microstructure mixture of heat treated structure and annealed structure was stated in the microsection.
Rod wire 10,00 mm round - quenched and tempered