The paper presents the wear behaviour on a rotating disk which carried abrasive paper of laser cladding layers with high-speed steel powder type HS6-5-2 - M2 compared to steel samples of the same quality but heat treated in volume. To see how temperature affects the wear behaviour by abrasion of the laser cladding alloy and the classically hardened steel, samples have been heated to 450 °C, 550 °C, 650 °C and 700 °C during a four hour exposure, after which they were subjected to testing. It was monitored the hardness and wear mass variation with temperature and the variation of micro-hardness in the laser cladding layer. In order to point out the microstructural aspects of the samples metallographic analyses were performed

Elena DRUGESCU

Simona BOICIUC

The Annals of “Dunarea de Jos” University of Galati Fascicle IX Metallurgy and Materials Science

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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
 
 
RESEARCH ON ABRASIVE WEAR BEHAVIOR OF  
LASER CLADDING LAYERS OF HIGH - SPEED STEEL  
POWDER TYPE HS6-5-2 - M2 
 
Simona BOICIUC, Elena DRUGESCU 
“Dunărea de Jos” University, Galaţi 
email: simonaboiciuc@yahoo.com 
 
ABSTRACT 
 
The paper presents the wear behaviour on a rotating disk which carried abrasive 
paper of laser cladding layers with high-speed steel powder type HS6-5-2 - M2 
compared to steel samples of the same quality but heat treated in volume. To see how 
temperature affects the wear behaviour by abrasion of the laser cladding alloy and 
the classically hardened steel, samples have been heated to 450°C, 550°C, 650°C 
and 700°C during a four hour exposure, after which they were subjected to testing. It 
was monitored the hardness and wear mass variation with temperature and the 
variation of micro-hardness in the laser cladding layer. In order to point out the 
microstructural aspects of the samples metallographic analyses were performed. 
 
KEYWORDS: laser cladding, high-speed steel, tool, powder, injection 
 
1. Introduction 
 
Laser cladding is one of the laser surface 
treatments. It was defined like a process used to melt, 
on a sub-layer, with a laser beam, a material with 
different metallurgical properties. With this technique 
particles of a second material are deposited and 
melted onto the substrate in order to form a dense 
layer on top of the substrate. The resulting laser 
treated surfaces have the advantage of being dense, 
homogeneous, and have a superior bonding across the 
surface. In order to keep the genuine properties of the 
cladded material, a very thin layer of the sub-layer has 
to be melting, in order to get a minimum dilution (0.5 
– 3%) of metallurgical bond of addition material and 
sub-layer material [1, 2]. Several methods can be 
applied.  
The clad material can be pre – placed and then 
melted together with the underlying substrate by the 
laser. Another method is to blow the clad material on 
the surface while blowing a shield gas protecting the 
laser optics from sputtering material. 
Laser cladding can be used to good effect in 
processes which require a high productivity combined 
with flexibility without compromising on quality. 
The paper presents the wear behaviour on rotating 
disk with abrasive paper of laser cladding layers with 
high-speed steel powder type HS6-5-2 - M2 compared 
with steel samples of the same quality but heat treated 
in volume. 
2. Experimental conditions 
 
For deposition use was made of powder of high-
speed steel type HS6-5-2 - M2, SR EN ISO 
4957/2002 (Rp 5, STAS 7382/1988) having the 
following chemical composition 0.82% C, 4.7% Mo, 
6, 4% W, 0.3% Mn, 4.1% Cr, 0.32% Si and 2.02% V, 
and Fe [3, 4]. By sieving the grain fractions were 
separated  in the range 80-90 μm to be used as added 
material. The powder had a spherical shape, which 
provided a smooth flow of the material additive 
through the injection system. Before placing the 
added material in the injection tank, the powder was 
dried at a temperature of 110oC for 15 minutes [3, 4]. 
The basic material used in the experimental 
research is steel 1C45, SR EN 10083-1:1994. 
Laboratory experiments were conducted on a CO2 
continuous wave system, type 1400W Laser GT 
(Romania), with working mass in x-y-z coordinates 
and computer programming of the working regime, 
provided with a powder injection system on the 
melted surface by means of laser, existing in SC 
UZINSIDER ENGINEERING Galaţi. 
For the laser cladding it was used a laser beam of 
1.8 mm diameter on the treated surface, at 1100 W 
power, scanning speed 5mm/s, by means of which 
partly overlapping parallel strips were deposited with 
a transverse step advance of 2 mm. The flow rate of 
the material added was 134mg/s. Final thickness of 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
the deposited layer was 1.5 mm resulting in 5 
overlapping layers. 
The samples of steel Rp5 were quenching at 
1220°C, with a subsequent triple annealing for one 
hour at 560°C. 
To see how temperature affects the wear 
behaviour by abrasion of the laser deposited alloy and 
the classically hardened steel, samples have been 
heated to 450°C, 550°C, 650°C and 750°C during 
four hour exposure, after which were subjected to 
testing. The abrasive wear behavior of laser deposited 
layers with the nickel base alloy has been studied 
according to STAS 9639-81.  
The method uses a connection of peg/disk friction 
of class IV-1. The method consists in pressing 
sequentially, under identical conditions, two samples 
of dimensions 6.2x6.2 mm, one of the material 
examined deposited by laser and the other from a 
material chosen for comparison purpose – improved 
high - speed steel Rp5 classical quenching on a 
rotating disk covered with grinding paper of  120 
grains. A mechanism for radial displacement of the 
tube with 0.5mm/r provides a spiral movement on the 
surface of the rotating disk. 
A device for implementing a load of 8.387 N 
ensured perpendicular pressing of the sample on the 
grinding paper at a pressure of 0.215N/mm2. At disk 
speed of 25rpm, a number of 131 rotations have 
provided a length path of 82m. 
It was monitored the hardness and wear mass 
variation with temperature and the variation of micro-
hardness profile plotting HV0,1 (load 0,98N) in the 
cross-section of the laser cladding layer. 
 
3. Experimental results and discussions 
 
The samples where laser deposit was performed 
with high – speed steel powder type M2, the 
classically hardened samples and the support were 
subjected to wear testing on a rotating disc with 
abrasive paper. The results are presented in Table 1, 
which is the average of three determinations. 
It may be noted that the laser cladding alloy is 
more resistant to abrasive wear than steel samples 
classically hardened, and especially to support. To see 
how temperature affects the wear behaviour by 
abrasion of the laser cladding alloy  (code A, B, C, D) 
and the classically  hardened steel (code 1, 2, 3, 4), 
samples were heated to 450°C, 550°C, 650°C, 700°C 
and exposed for four hours, after which they were 
tested. 
 
Table 1. Abrasive wear behaviour of the support, the deposit of high – speed powder, and the 
classically hardened high – speed steel unaffected by temperature 
 
 
The results after heating are given in Table 2 and 
those obtained after wear tests are given in Table 3. 
Table 2 shows the samples code, the heat conditions 
and the hardness obtained on the surface of the 
samples. The variation of hardness vs. heating 
temperature is shown in Fig. 1.  
                       
Table 2. The heat conditions and hardness of the samples 
 
Heating temperature Exposure time Initial hardness HV5 
Final hardness  
HV5  Sample code 
[°C] [h] [MPa] 
A 450 4 9860 
B 550 4 9560 
C 650 4 7810 
D 700 4 
10490 
5280 
1 450 4 8910 
2 550 4 8570 
3 650 4 7010 
4 700 4 
8910 
4940 
Initial mass Final mass  Mass wear n Material [g] [rotations] 
1C45 2.9150 2.7270 0.1870 131 
Laser cladding M2 3.1638 3.0818 0.082 131 
High – speed steel classically 
quenching 2.6625 2.5608 0.1017 131 
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FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
0
2000
4000
6000
8000
10000
12000
450 550 650 700
temperature, 0C
ha
rd
ne
ss
, H
V5
, [
M
Pa
]
 laser cladding ordinary quenching
 
 
Fig. 1. Variation of hardness with heating temperature for  
laser cladding samples and quenching samples. 
 
Analyzing Table 2 and Figure1, it can be noticed 
that, as the heating temperature increases there is a 
decrease in hardness for both in laser cladding layers 
and classically treatment samples. However the 
hardness of the laser layer is maintained at higher 
values as compared with the classical treatment of 
steel Rp5. Thus the minimum hardness of 58HRC is 
reached by the laser cladding at 690°C, while the 
classically quenching steel at 650°C. This may be 
correlated with the fact that with  laser cladding, the  
ultra rapid cooling speed causes hardening since the 
liquid phase with the formation of more alloyed 
austenite by  dissolution of the secondary and part of 
the primary carbides, chemically non homogenous, 
finer grains and increased amount of structural 
defects. High cooling speed guaranteed martensite 
transformation that inherits the austenitic 
characteristics, together with an increased amount of 
residual austenite. Recrystallization at overlaps 
favored dispersed precipitation of the carbides and 
diminished the amount of residual austenite. 
Upon heating within the range of 450-700 °C, the 
high-alloyed martensite featured higher thermal 
stability than the martensite obtained by the classical 
volume treatment and implicitly higher hardness at 
the same heating temperature. 
To highlight the microstructural aspects of the 
heated samples, metallographic analyses were 
performed at 500x magnifying, both for those with 
laser cladding and those obtained classically, the 
metallographic attack being made with nital 2%. They 
are given in Fig. 2 and 3. 
From Fig.2 it can be seen a dendritic structure 
specific to the laser cladding with numerous carbides. 
From Fig.3 it can be seen that as the heating 
temperature increases coalescence of carbides takes 
place along with lower degree of dispersion, which 
leads to lower hardness. 
 
A.a  
 
A.b 
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N0. 4 – 2010, ISSN 1453 – 083X 
 
 
B.a B.b 
  
C.a C.b 
  
D.a D.b 
 
Fig.2. Microstructures of the laser cladding layers with powder of high-speed  steel heated at different 
temperatures for samples  code A - 450°C, B - 550°C, C - 650°C, D - 700°C: a)- layer base, b- layer 
surface (x500). Nital attack  2%. 
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FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
1 2 
3 4 
 
Fig.3. Microstructures of high-speed steel Rp5 classically heated at different temperatures for samples 
code 1 - 450°C, 2 - 550°C, 3 - 650°C, 4 - 700°C (x500). Nital attack 2%. 
 
0
2000
4000
6000
8000
10000
12000
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
distance from surface, [mm]
m
ic
ro
ha
rd
ne
ss
 H
V0
.1
, 
[M
Pa
]
sample A sample B sample C sample D
 
 
Fig.4. Variation of  microhardness of the cladding layer after heating for samples code A – 450°C, 
code B – 550°C, code C – 650°C, code D – 700°C.            
 
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FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
According to qualitative phase analysis [3], the 
microstructure of the deposited layers heated at 
different temperatures contain martensite, residual 
austenite and eutectic colonies of carbides 
interdendritically spaced and at the grain limit, the 
basic hardening phase being Cr7C3. Variation of 
microhardness of the laser layer with high - speed 
steel type M2 obtained after heating the samples code 
A, B, C, D at 450°C, 550°C, 650°C, 700°C with a 
four hour exposure time.  
Results are given in Fig.4. Table 3 presents results 
from wear tests (mass wear, mass wear/length of path 
covered) in rotating disk with abrasive paper both 
laser cladding samples and those classically hardened 
in volume. 
 
Tabel 3. The samples abrasive wear behaviour after heating at several temperatures 
 
Heating 
temperature 
Keeping 
time 
Initial 
mass  
Final 
mass  
Mass 
wear U/L Sample cod [°C] [h] [g] [g/m] 
A 450 2.9865 2.9030 0.0835 0.00104 
B 550 2.9781 2.8929 0.0852 0.00107 
C 650 3.1055 2.9881 0.1174 0.00136 
D 700 3.1118 2.9478 0.164 0.00202 
1 450 2.6625 2.5599 0.1026 0.00123 
2 550 2.5827 2.4792 0.1035 0.00126 
3 650 2.7234 2.5982 0.1252 0.001502 
4 700 
4 
2.6004 2.4306 0.1698 0.002093 
 
It is noted that heating at different temperatures 
affects the wear behaviour of the deposit.  
Thus as the temperature increases the wear 
resistance decreases at temperatures higher than 
650°C, which is due to coalescence carbides and 
decrease in their dispersion. Fig. 5 and Fig. 6 show 
the variation of mass wear and the ratio of wear 
mass/length of path covered with the heating 
temperature for samples: code A, B, C, D and code 1, 
2, 3, 4. 
0
0.05
0.1
0.15
0.2
20 450 550 650 700
temperature, [0C]
w
ea
r, 
[g
]
ordinary quenching laser cladding
 
Fig.5. The variation of mass wear with the heating temperature for samples:  
code A, B, C, D and code 1, 2, 3, 4. 
0
0.0005
0.001
0.0015
0.002
0.0025
20 450 550 650 700
temperature, [0C]
U
/L
, [
g/
m
]
ordinary quenching laser cladding
 
Fig.6. The variation of the ratio of wear mass / length of path covered with the heating temperature 
for samples: code A, B, C, D and code 1, 2, 3, 4. 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 4 – 2010, ISSN 1453 – 083X 
 
 
Analyzing the above figures it may be noted that 
the wear mass and wear ratio mass/length of the path 
covered increase with increasing temperature, more 
pronounced at values higher than 650°C, which is due 
to coalescence carbides and decrease in their 
dispersion. 
 
4. Conclusions  
 
As regards thermo-stability of the laser cladding  
with high - speed steel powder  M2 and heat treated 
samples in volume it was found that as heating 
temperature increases there is a decrease in their 
hardness because of coalescence carbides and their 
decreased dispersion.  
Abrasive wear behaviour of laser cladding layers 
of high - speed powder M2 showed a higher 
resistance compared to steel 1C45, and Rp5 
classically hardened steel.  
The ultra rapid cooling speed in laser cladding 
causes hardening since the liquid phase with the 
formation of more alloyed austenite by dissolution of 
the secondary and part of the primary carbides, 
chemically non homogenous, finer grains and 
increased amount of structural defects.  
High cooling speed guaranteed martensite 
transformation that inherits the austenitic 
characteristics, together with an increased amount of 
residual austenite.  
Recrystallization at overlaps favored dispersed 
precipitation of the carbides and diminished the 
amount of residual austenite. 
With respect to abrasive wear resistance of the 
laser cladding layers, heated at different temperatures 
it can be observed that the mass wear and the ratio of 
mass wear/length of the road covered increase with 
higher temperature, even more at values higher than 
650°C, which is due to coalescence carbides and their 
decreased dispersion.  
Also the dilution zone is changed which is visible 
due to the decrease in the difference in hardness 
between the cladding layer and the substrate. 
 
Reference 
 
[1]. M.F. Schneider - Laser cladding with powder, Ph. D. Thesis 
University of Twente, Enschede, Olanda, 1998. 
[2]. H. Gedda – Laser surface cladding - a literature survey, Lulea 
University of Technology, Division of Materials Processing, iulie 
2000, Suedia. 
[3]. D.T. Levcovici, R. Boiciuc, S.M. Levcovici, C. Gheorhieş – 
Laser cladding of M2 steel on a steel substrate, The International 
Thermal Spray Conference and Exposition (ITSC), may 15th – 17th, 
2006, pp. 1333-1338 Seattle, USA (ISBN 0-87170-836-1). 
[4]. 1. D.T. Levcovici, S.M. Levcovici, I. Onea – Procedure of 
laser cladding of high speed steel, Patent 121477 B1 din 
30.04.2007. 
 
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Research on Abrasive Wear Behavior of Laser Cladding Layers of High - Speed Steel Powder Type HS6-5-2 - M2

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Research on Abrasive Wear Behavior of Laser Cladding Layers of High - Speed Steel Powder Type HS6-5-2 - M2

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