Abstract
Hard wear resistant surface layers of
transition metal carbides can be produced by
thermo-reactive diffusion processes where
interstitial elements from a steel substrate together
with external sources of transition metals (Ti, V,
Cr etc.) form hard carbide and/or nitride layers at
the steel surface. In this study halide-activated
pack cementation techniques were used on tool
steel Vanadis 6 and martensitic stainless steel AISI
420 in order to produce hard layers of titanium
carbide (TiC), vanadium carbide (V8C7) and
chromium carbides (Cr23C6 and Cr7C3). Surface
layers were characterized by scanning electron
microscopy, X-ray diffraction and Vickers
hardness testing. The study shows that porosityfree,
homogenous and very hard surface layers can
be produced by thermo-reactive diffusion
processes. The carbon availability of the substrate
influences thickness of obtained layers, as Vanadis
6 tool steel produces thicker layers than AISI 420.
X-ray diffraction analysis validates the formation
of TiC and V8C7 layers on titanized and vanadized
samples respectively, while chromized samples
form both Cr23C6 and Cr7C3. It is shown that the
two-phase layer of Cr23Cr6/Cr7C3 produced on
Vanadis 6 can be transformed into a layer much
richer in Cr7C3 and poorer in Cr23C6 by a
subsequent heat treatment. The produced
chromium-, vanadium- and titanium carbide layers
have hardness values of 2116±37HV,
3022±119HV and 3951±66HV respectively, and
subsequent hardening and tempering of treated
materials can be done without spallation of the
hard layers.
Original language | English |
---|---|
Title of host publication | Surface Modification Technologies XXVIII. Proceedings of the Twenty Eighth International Conference on Surface Modification Technologies |
Editors | T.S. Sudarshan, P. Vuoristo, H. Koivuluoto |
Publisher | VALARDOCS |
Publication date | 2015 |
Pages | 643-654 |
ISBN (Print) | 978-81-926196-1-3 |
Publication status | Published - 2015 |
Event | 28th International Conference on Surface Modification Technologies - Tampere University of Technology, Tampere, Finland Duration: 16 Jun 2014 → 18 Jun 2014 Conference number: 28 http://www.tut.fi/en/international-conference-on-surface-modification-technologies/index.htm |
Conference
Conference | 28th International Conference on Surface Modification Technologies |
---|---|
Number | 28 |
Location | Tampere University of Technology |
Country/Territory | Finland |
City | Tampere |
Period | 16/06/2014 → 18/06/2014 |
Internet address |