20-55 TRANSFORMĂRI STRUCTURALE ALE OŢELULUI LEDEBURITIC X200Cr12 ÎN URMA APLICĂRII UNUI TRATAMENT TERMIC ŞI CRIOGENIC


STRUCTURAL TRANS FORMATIONS
OF THE X200Cr12 LEDEBURITIC STEEL AFTER A
CRYOGENIC HEAT TREATMENT
Cryogenic treatment completes the classic heat treatment of steels
with higher carbon content of 0.6 %, bringing substantially improving on
properties, being very simple.
In the case of X200Cr12 ledeburitic steel, the amount of residual
austenite was reduced from 20.03 % to 14.14 %, being transformed into
martensite, as a result of cryogenic treatment done immediately after
quenching.
Hardness Vickers values were increased with 61 units, representing a
6.7 % increase, as a result of martensitic transformation.
Keywords: steel ledeburitic X200Cr12, X-ray diffraction, martensitic
transformation, optical microscopy, low temperature
Cuvinte cheie: oţel ledeburitic X200Cr12, difracţie cu raze X,
transformare martensitică, microscopie optică, temperaturi scăzute

55 TRANSFORMĂRI STRUCTURALE ALE OŢELULUI