科研之友
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摘要
Purpose: This work presents results of investigations using M ssbauer spectroscopy technique and their interpretation concerning transformation of 汍 to cementite carbides during tempering in relation to previously conducted dilatometric, microscopic and mechanical investigations. Investigations were performed on 120MnCrMoV8-6-4-2 steel.Design/methodology/approach: Samples taken from investigated steel were austenitized at the temperature of 900oC and hardened in oil. Austenitizing time was 20 minutes. After that, seven of eight samples were tempered. Tempering consisted of holding the samples at 200～C for defined periods. All the times mentioned above were selected basing on IHT (Isothermal Heating Transformations) diagram.Findings: The influence of the tempering time on nucleation and solubility of 汍 carbides, and on cementite nucleation and growth, was determined.Research limitations/implications: The analysis of phase transformations during various periods of tempering using M ssbauer spectroscopy technique made possible to reveal fine details connected with the processes.Practical implications: Optimum tempering time of tools made from the investigated steel should be in the range of 1.5-2h.Originality/value: Details descriptions of 汍 to cementite carbides transformation during isothermal heating from as-quenched state.
