Various small metal forming tools utilized in hot extrusion of non-ferrous metals and alloys are susceptible to severe wear and sticking at high temperatures, thermal softening and fatigue leading to premature failures and extra interruptions in production due to frequent tool replacements. Laser cladding combined with appropriate material selection proved to be a suitable technique to increase the tool life significantly. To implement this, a fully closed-loop semi-automatic laser cladding cell was developed. The procedure consists of induction unit for preheating and Nd:YAG laser for cladding, which both are adaptively controlled. In order to clad more than one surface of the tool, the most flexible way to do the cladding was to keep the laser and powder nozzle stationary while the robot manipulates the tool. Due to small dimensions of the tool and cooling channels beneath the surface to be clad, heat accumulates largely during the cladding process, which leads to increasingly higher levels of dilution and lower levels of hardness between different surfaces. Using adaptively controlled laser power, surfaces with equal dilution and hardness were obtained. With adaptively controlled induction heating unit, preheating phase of the process was suppressed down to minimum, and accuracy as well as repeatability was improved substantially compared with conventional preheating methods, which are also impractical in serial production.

1.
Björk
,
T.
,
Bergström
,
J.
&
Hogmark
,
S.
(
1999
)
Tribological simulation of aluminium hot extrusion
,
Wear
224
,
216
225
.
2.
Weerasinghe
,
V. M.
&
Steen
,
W. M.
(
1987
)
Laser cladding with blown powder
,
Metal Construction October
1987
,
581
585
.
3.
Hutchings
,
I. M.
(
1996
)
Tribology – Friction and Wear of Engineering Materials
, 4th edition,
Arnold
,
London, UK
,
206
pp.
4.
Deloro Stellite Group
(
2003
)
Wear solutions for a world of motion
,
Presentation material of Deloro Stellite Company Inc
.
5.
Ocken
,
H.
(
1999
)
Performance of NOREM™ hardfacing alloys
,
EPRI
,
Palo Alto. CA
: 1999, TR-112993
6.
Persson
,
D.H.E.
(
2005
)
On the mechanisms behind the tribological performance of Stellites
, Doctoral thesis,
Uppsala Universitet
,
Sweden
.
7.
Kim
,
J. K.
&
Kim
,
S. J.
(
2000
)
The temperature dependence of the wear resistance of iron-base NOREM 02 hardfacing alloy
,
Wear
237
,
217
222
.
8.
Massalski
,
T. B.
,
Murray
,
J. L.
,
Bennett
,
L. H.
&
Baker
,
H.
(
1986
)
Binary Alloy Phase Diagrams
Vols.
1 & 2
,
American Society for Metals
,
Metals Park, OH, USA
.
9.
Predel
,
B.
&
Madelung
,
O.
(
1998
) Landolt-Bornstein, Group IV Physical Chemistry – Phase Equilibria, Crystallographic and Thermodynamic Data of Binary Alloys, Volume
5
Light Metal Structural Alloys
,
Springer - Verlag
.
10.
Grobner
,
P.
,
Ohriner
,
E. K.
,
Wada
,
T.
&
Whelan
,
E. P.
(
1989
)
NOREM wear-resistant iron-based hard-facing alloys
,
EPRI
,
Palo Alto. CA
: 1989, NP-6466-M
13.
Outokumpu HSC Chemistry Version 4.0
(
1999
)
Chemical Reaction and Equilibrium Software with Extensive Thermochemical Database
14.
Hou
,
Q. Y.
,
Gao
,
J. S.
&
Zhou
,
F.
(
2005
)
Microstructure and wear characteristics of cobalt-based alloy deposited by plasma transferred arc weld surfacing
,
Surface & Coatings Technology
194
,
238
243
.
15.
d’Oliveira
,
A. S. C. M.
,
Vilar
,
R.
&
Feder
,
C. G.
(
2002
)
High temperature behaviour of plasma transferred arc and laser Co-based alloy coatings
,
Applied Surface Science
201
,
154
160
.
16.
Crook
,
P.
(
1990
) Cobalt and Cobalt Alloys,
ASM Handbook
, Vol.
2
, 10th ed.,
446
454
.
This content is only available via PDF.
You do not currently have access to this content.