Examinations at the material 1.3401

 

The series of experiments was made to get knowledge about the hardness acceptance and crystalline structures at the material X120Mn12.
Initial condition : hot rolled 14,00 mm , unpickled    Heat treatment : laboratory furnace (volume 2 liter)

Annealing : holding time 45 minutes      quenching in water , air and furnace cooling
Tempering : holding time 30 minutes , 1 hour , 4 hours , 16 hours      cooling at air

In the solution annealed and quenched condition this hard manganese steel has an austenitic structure and is non-magnetic. The austenit is supersaturated with carbon at this time. However, one cools down slowly, mixed carbides (alloyed cementite ; (Fe,Mn)3C) are precipitated predominantly on the grain boundaries, but also as acicular precipitates in the grain. If the steel gets tempered at higher temperatures, sorbite is formed out of the austenite and after a longer holding time also martensite. In this condition the material gets magnetic. With an increasing transformation of the austenite to sorbite and martensite the hardness rises strongly.

           CCT-diagram to this material 

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