Effect of different heat treatment regimes on the structure and properties of martensitic steel 90Kh18M

Previously abstracted from original as item 9108-56-0933. Astudy was done on the effect of various heat treatments on structure, tensile, impact and torsional properties of 90Kh18M, 50Kh14MF and 100Kh13M steels. The hardness of 90Kh18M steel after quenching or tempering resulting from quenching from the 900-1250 deg C range varied considerably due to the change in carbon content of the martensite from 0.40 to 0.50% (increase in hardness) and the increase in amount of residual austenite from 1 to 93% (decrease in hardness). At temperatures < Ac sub 1 in high-C martensitic steels of type 50Kh14MF and 100Kh13M, a temperature region was observed at which a high amount of austenite was formed, probably due to the occurrence of the reverse alpha - > gamma transformation. A sharp decrease in ductility of 90Kh18M steel occurred at test temperatures of 1200 deg C and higher as a result of liquation of the austenitic grain boundaries. The following heat treatment was recommended for 90Kh18M steel: quench from 1050 deg C and temper at 140 deg C (hardening treatment) or anneal at 750 deg C (softening treatment). Graphs, Photomicrographs.