Diffusion kinetics of boron in the X200CrMoV12 high-alloy steel

• Published in: Journal of mining and metallurgy. Section B, Metallurgy Vol. 51; no. 1; pp. 49 - 54
• Main Authors: Azouani, O, Keddam, M, Brahimi, A, Sehisseh, A
• Format: Journal Article
• Language: English
• Published: Bor Technical Faculty Bor, University of Belgrade 01-01-2015; Technical Faculty, Bor
• Subjects: Activation energy; Borides; Boriding; Boron; Diffusion; High alloy steels; Iron borides; Kinetics; Mathematical models; Metallurgy; Regression model; Silicon carbide
• ISSN: 1450-5339; 2217-7175
• DOI: 10.2298/JMMB140404009A

In this article, the kinetics of the boride layers (FeB/Fe2B), formed on the X200CrMoV12 steel used for the cold-working, was investigated. The boriding treatment was carried out in the powder mixture consisting of 5%B4C, 5% NaBF4 and 90% SiC. The boriding parameters are : 900, 950 and 1000 degrees Celsius with treatment times of 2, 4 and 6 h. The obtained borided layers (FeB/Fe2B) were characterized by the following experimental techniques: optical microscopy, scanning electron microscopy coupled to EDS analysis and XRD analysis. The kinetics of boron diffusion in the X200CrMoV12 steel was also studied. As a result, the time dependence of the borided layers thicknesses followed a growth parabolic law. A full factorial design with 2 factors at 3 levels was employed to estimate the total boride layer thickness as a function of the boriding parameters (time and temperature) and a simple equation was proposed. Finally, an iso-thickness diagram was given, as a tool to predict the total boride layers thicknesses in relation with the practical utilization of this kind of steel.