Effects of Nitriding Subsequent Titanaliting of Steels

Andrei Mihai GHINEA; Mihai Ovidiu COJOCARU; Leontin Nicolae DRUGÀ

doi:10.35219/mms.2020.2.07

Andrei Mihai GHINEA Politehnica University of Bucharest, Romania
Mihai Ovidiu COJOCARU Politehnica University of Bucharest, Romania; Academy of Technical Science of Romania
Leontin Nicolae DRUGÀ UTTIS Industries Bucharest, Romania; Academy of Technical Science of Romania

DOI: https://doi.org/10.35219/mms.2020.2.07

Keywords: titanaliting, nitriding, thermodynamics of the conversion of aluminides to nitrides, formation of kinetic layer, optical microscopy, electronic microscopy

Abstract

The paper presents the results of nitriding in partially dissociated ammonia of the pure technical iron, respectively 34CrAlMo5 steel after titanaliting in powdery solid medium, with direct reference on the growth kinetics of the layers, the phase composition and the morphology of the resulting layers. Thermodynamics was anticipated and experimentally demonstrated that the layers of titanium aluminide formed on the surfaces of the two metallic materials considered do not constitute barriers to nitrogen diffusion during the nitriding process, but actively participate in the formation of simple or complex nitrides of the two elements, titanium and aluminum. On the other hand, in the presence of these layers, the flux of nitrogen atoms is slightly diminished with repercussions on the dimensions of the structural components of the layer. The conclusion of the experimental research was that the role of titanaliting prior to nitriding is to increase the proportion of the hardening phases in the surface layers of thermochemically processed metal products after nitriding.

Downloads

Download data is not yet available.

References

[1]. Lahtin Iu. M., Kogan Ia. D., Azotirovanie stali Moskva, Maşinostroenie, p. 19-44, 1976.
[2]. Lahtin Iu. M., Arzamasov B. N., Himico-termiceskaia obrabotka stali Moskva, Metallurghia, p. 141-154, 1985.
[3]. Iurghenson A. A., Azotirovanie v energostroenie Moskva, Maşghiz, 1962.
[4]. Lahtin Iu. M., Kogan Ia. D., Spies H. J., Böhmer S., Teoria i tehnologhia azotirovania, Izd Metallurghia & Izd VEB Deutscher Verlag für Grundstoffindustrie, p. 144-182, Leipzig 1991.
[5]. J. Zýsk, Gefüge von ε-Schichten carbonitrierter unlergierte Stȁhle in abhȁngigkeit von ihrer Kohlenstoffkonzentration, Hȁrterei Technische Mitteilungen, B, p. 319-324, 1976.
[6]. Zâsik Ia., Tatcikovskii Ia., Sulkovskii I., Formirovanie diffuzionnih sloev pri gazovom azotirovanii, Metallovedenie i termiceskaia obrabotka metallov, nr. 6, p. 12-15, 1980.
[7]. Gentao Bu, Yuan Gao, Chenglei Wang, Research on Corrosion Resistance of Titanizing and Nitriding on Carbon Steel in H2SO4 solution, Materials Science Forum, vol. 704-705, p. 1152-1160, 2012.
[8]. Ozkan Cegila, Saduman Senb, Formation of Titanium Aluminum Nitride Layers on AISI D2 Steel by Nitro-Titanizing Treatment, 2nd International Advances in Applied Physics and materials Science Congress, p. 109-113, 2012.
[9]. Jiawei Xua, Lingbo Tang, Long Chenb, Study on Microstructure and Mechanical Properties of Nitrided and Titanized Carbon Steel, IOP Conference Series: Materials Science and Engineering, 782, 2020.
[10]. Mittemeijer E. I., Nitriding of binary and ternary iron-based alloys, vol. Thermochemical Surface Engineering of Steels, edited by Mittemeijer E. I. and Somers-Woodhead M. A. J., Publishing in Metals and Surface Engineering, nr. 62, p. 313-354, 2015.
[11]. Florian E., Cojocaru M., Aspecte privind termodinamica şi cinetica disocierii amoniacului in timpul incălzirii la nitrurarea şi carbonitrurarea oţelurilor, Metalurgia, nr. 6, 1978.
[12]. Cojocaru M., Florian E., Cementarea cu azot, rezultat al schimbului de electroni între metal şi ammoniac, Metalurgia, nr. 7, 1978.
[13]. Cojocaru M., Florian E., Comportarea amoniacului in timpul incălzirii, explicate prin mecanismul ionic de adsorbţie, Metalurgia, nr. 9, 1978.
[14]. Mondolfo L. F., Structura I svoistva aliuminievâh splavov, Moskva, Metallurghia, p. 67-73, 1979.