Optimisation of different laser processes requires control over the fundamental parameters of laser processing i.e. heating / cooling rate and thermal gradient. Different processes have different requirement of heating/cooling rate and thermal gradient. If we can control these parameters we can optimise laser processing of materials. Knowing these parameters and relevant metallurgical information we can predict the microstructure and hence control the material properties. The effect of laser beam geometry on laser processing of materials has received very little attention. Laser material processing have been carried out in the past using circular or rectangular beams. This paper presents an investigation of the effects of different beam geometries including circular, rectangular and triangular shapes. Finite element modelling technique has been used to simulate the transient effects of a moving beam for laser surface heating of metals. The temperature distributions, cooling rates and thermal gradients have been calculated. Some of the results have been compared with experimental data.

1.
Incropera
,
Dewit
,
Fundamentals of Heat Transfer
, 4th Ed., Pub.
John Wiley and Sons, Inc
2.
Sandven
,
O.
,
Laser Surface Transformation Hardening
. Metals Handbook, 9th Ed., Vol.
4
: Surface Engineering, Pub.
ASM
, pp
507
517
.
3.
Autorenkollektiv
, The Pyrometer Handbook,
IMPAC Electronic GmbH
.
4.
Woolman
,
J.
,
Mottram
,
R.A.
,
The Mechanical and Physical Properties of the British Standard EN Steels
, Vol.
3
, First Ed.,
1968
,
Pergamon Press Ltd
. Journal paper
5.
Wei
,
P.S.
,
Ho
,
C.Y.
,
Shian
,
M.D.
,
Hu
,
C.L.
,
Three-Dimensional Analytical Temperature Field and its Application to Solidification Characteristics in High- and Low-Power-Density-Beam Welding
.
Int. J. Heat and Mass Transfer.
Vol.
40
:
1997
, pp.
2283
2292
6.
Shuja
,
S.Z.
,
Yilbas
,
B.S.
,
3-Dimensional Conjugate Laser Heating of a Moving Slab
.
App. Sur. Sci.
Vol.
167
:
2000
, pp.
134
148
7.
Kar
,
A.
,
Scott
,
J.E.
,
Latham
,
W.P.
,
Effects of Mode Structure on Three Dimensional Laser Heating Due to Single or Multiple Rectangular laser beams
.
J. Appl. Phys.
Vol.
80
: July,
1996
, pp.
667
674
8.
Dai
,
K.
,
Shaw
,
L.
,
Thermal and Stress Modelling of Multi-Material Laser Processing
.
Acta Mater
, Vol.
49
:
2001
, pp.
4171
4181
9.
Matsumoto
,
M.
,
Shiomi
,
M.
,
Osakada
,
K.
,
Abe
,
F.
,
Finite Element Analysis of Single Layer Forming on Metallic Powder Bed in Rapid Prototyping by Selective Laser Processing
.
Int. J. Mach. Tools Manuf.
Vol.
452
:
2002
, pp.
61
67
10.
Yeung
,
K.S.
,
Thornton
,
P.H.
,
Transient Thermal Analysis of Spot Welding Electrodes
.
Supplement to the Welding Journal
: January,
1999
, pp.
1s
6s
11.
Chen
,
Y.X.
,
He
,
Y.Y.
,
Jun
,
P.S.
,
Nian
,
S.J.
,
The Role of Beam shape in Convection and Heat Transfer in Laser Melted Pool.
Proceedings of ICALEO ’90
, Nov.
1990
,
Boston, USA
, Vol.
82
: pp.
480
491
.
12.
Shankar
,
V.
,
Gnanamuthu
,
D.
,
Computational Simulation of Heat Transfer in Laser Melted Material Flow.
AIAA 24ᵗʰ Int. Aerospace Sci. Meeting
,
Reno, Nevada
:
1986
, pp.
1
10
13.
De Kock
.,
J.
,
Lasers Offer Unique Heat Treating Capabilities
.
Industrial Heating
:
2001
via URL www.industrialheating.com.
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