+44 (0)1509 263171
Please use this identifier to cite or link to this item:
|Title: ||Titanium nitrate coated high speed steel cutting tool inserts|
|Authors: ||Whittle, Neville C.|
|Issue Date: ||1987|
|Publisher: ||© N.C. Whittle|
|Abstract: ||A detailed study has been made of commercially produced, powder
metallurgy, BT42 grade high speed steel (H.S.S.) indexable cutting
tool inserts coated with a thin layer of titanium nitride (TiN) by
chemical vapour deposition (C.V.D.).
The characteristics of the coating before and after the obligatory
substrate heat treatment were first ascertained using various techniques
including X-ray diffraction, Auger electron spectroscopy,
fractography, scanning and transmission electron microscopy, microhardness
testing, profilometry, optical microscopy and scratch-adhesion
testing. It was found that the characteristics of the TiN coating were
not significantly affected by the substrate heat treatment and that they
were comparable to those presented in the literature for similar C.V.D.
coatings on cemented carbide inserts. The cutting properties of the fully characterised TiN coated
H.S.S. inserts were then compared to those of uncoated inserts in a
series of turning tests on 817M40 workpiece material, carried out under
conditions of built-up edge (b.u.e.) formation at cutting speeds in the
-1 range 30-60 m min. Comparison of the inserts with regard to tool
life, tool wear, tool forces, apparent coefficient of friction, b.u.e.
formation and workpiece surface finish, revealed that the TiN coated
inserts had significantly improved cutting properties relative to the
uncoated inserts. Additional tests showed that increasing coating
thickness led to further improvements in cutting performance. The role
of the TiN coating was studied from metallographic sections through worn
inserts, and the reasons for its significant effect on the cutting
properties of tbe H.S.S. inserts are discussed. Similar inserts coated with TiN by physical vapour deposition
(P.V.D.) were also characterised and their cutting performance determined.
The results obtained are compared to those for the C.V.D. TiN
coated inserts. Differences in the cutting performance are related to
the different characteristics of the two coatings arising from the
processes used for their deposition.|
|Description: ||A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Materials)|
Files associated with this item:
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.