In this paper, the performance of three cemented carbide cutting tools, two
coated tungsten based cemented carbide - one with Al2O3 (black) outer laye
r and the other with TiN (golden), and an uncoated titanium based (silver g
rey) cemented carbide tool, with 80 degrees - diamond insert shape were inv
estigated during finish turning of AISI 1010 steel. The PCBNR tool holder,
giving a side cutting edge angle of +15 degrees, was used. Cutting tests we
re performed with constant depth of cut and at various cutting speeds and f
eed rates to investigate the performance of the tools under dry cutting con
ditions. Cutting forces and surface roughness were measured. The chips prod
uced by the three type of tools during experimental trials were examined to
determine the secondary shear zone, chip thickness and the angle of maximu
m crystal elongation. The tool which had the CVD with TiCN/TiC and PVD with
TiN coating layer sequence performs best under the conditions tested, as l
ower forces with little variation were encountered, very good surface finis
h could be obtained and chips with minimum SSZ thickness could be produced,
that contributed to low chip strain and therefore to low residual stresses
on the workpiece surface. (C) 2001 Elsevier Science B.V. All rights reserv
ed.