TEMPERATURE BEHAVIOUR OF THE BORIDE LAYER OF A LOW-CARBON MICROALLOYED STEEL


UÇAR N. , Aytar O. B. , Calik A.

MATERIALI IN TEHNOLOGIJE, cilt.46, ss.621-625, 2012 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 46 Konu: 6
  • Basım Tarihi: 2012
  • Dergi Adı: MATERIALI IN TEHNOLOGIJE
  • Sayfa Sayıları: ss.621-625

Özet

In this work, the boronizing of low-carbon microalloyed steels was carried out in a solid medium using the powder-pack method. After boronizing, a boride layer and the presence of both FeB and Fe2B phases in the boride layer were revealed with classic metallographic techniques and X-ray diffraction (XRD) analysis. The presence and distribution of alloying elements on the boride phases was measured using glow-discharge optical emission spectrometry (GDOES) and the distance between the surface and the substrate was taken as the layer thickness. It was found that higher boronizing temperatures resulted in an increase in the layer thickness, from 7 mu m to 105 mu m. In addition, microhardness tests of the boronized steel samples showed a significant increase in the surface hardness caused by the increased boronizing temperature. The boride layer had a hardness of over 910 HV0.1 and 1320 HV0.1, for 973 K and 1273 K, respectively, while the substrate's hardness was approximately 145 HV0.1. Kinetic studies showed that the diffusion process is thermally activated, with the mean value of the activation energy being close to 194 kJ/mol.