engleski

Duplex Procedures of Heat Treatment of Steels

This paper presents investigation results of influence of thermodiffusion duplex treatment on improvement of surface layers created on low-carbon and low-alloyed steels. On chosen low-carbon and low-alloyed construction steels temperatures of phase transformations (A3 and A1) have been determined. First duplex results were achieved with procedures carburising + boronizing ; carburising (car. + 10 % BaCO3, 900 °C / 5 h), boronizing (Durborid 3, 900 °C / 4 h). Second duplex thermodiffusion heat treatment was boronising + nitriding ; boronizing (Durborid 3, 900 °C / 4 h), plasma nitriding has been performed afterwards. Deposition of elements, plasma nitriding (as a part of duplex treatment) has been performed on PN–Mono 5 device with following parameters 520 °C / 40 min, H2 / N2 = 70 / 30. As a result, stable layer of boride and nitride (FeB, Fe2B, BN and others) has been formed on steel surface. Results of investigation of structure have been presented through metallographic analysis and by Scanning microscope. Surface layers have been also analyzed through Röntgen diffraction (XRD).

Duplex treatment; Carburizing; Boronizing; Plasma nitriding

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