The wear resistance of commercial quenched wear resistant steels is commonly categorized by their Brinell hardness. The hardness grades are considered almost as standards, although they are not and there are no earlier evidence about their wear performance. In this study the differences of 15 different comercially available 400 HB grade steels were tested with natural granite gravel as abrasive material. The outcome was that the difference in abrasive wear perfomance can be more than 50 %. Nominally similar 400 HB grade quenched wear resistant steels do not perform equally under heavy abrasion wear, and hardness alone is not an accurate predictor of the steel’s wear performance. Alloying and manufacturing of the steel and thus its microstructure has a significant effect particularly on the work hardening behavior of the steel during abrasion, leading to different wear performances under such conditions.

1. Abrasion wear
performance of quenched
wear resistant steels
Niko Ojala1)*, Kati Valtonen1), Marke Kallio2), Joonas Aaltonen2),
Pekka Siitonen2) and Veli-Tapani Kuokkala1)
1) Tampere University of Technology,
Department of Materials Science, Tampere Wear Center, Finland
2) Metso Minerals, Inc., Finland
*email: niko.ojala@tut.fi
WTC 2013
Torino, Italy
8th – 13th September 2013

2. Motivation
• Quenched wear resistant steels are widely
used in industrial applications.
• The Brinell hardness grades are considered
as standards.
• But the wear performance is not extensively
studied.

3. Overview to topics
1) Materials and methods
2) Results
3) Discussion

4. 0.142
0.158
0.163
0.165
0.172
0.173
0.176
0.180
0.186
0.189
0.192
0.199
0.202
0.208
0.216
0
100
200
300
400
500
600
700
800
900
1000
0.000
0.050
0.100
0.150
0.200
0.250
0 2 15 4 14 3 10 11 5 24 18 17 6 16 1
Surfacehardness[HV5]
Massloss[g]15 commercially available
400 HB steels were tested
• Sheet thicknesses were 10 or 12 mm.
• Decarburization layers were removed before testing
• Five steels were selected to closer study.
A B C D E

5. Crushing pin-on-disk
• The equipment is based on the pin-on-disk
principle
• In the tests, the pin is repeatedly pressed against
the gravel bed and the disk with a pneumatic
cylinder
– The pin does not come into direct contact with the
disk at any time
• The loss of material of both the pin and the disk
are measured by weighting, and the size change of
the abrasive during the test can measure by sieving

7. Test parameters
• Disk speed: 20 rpm
• Disk material: S355 (200 HV)
• Pin pressure: 1.1 bar
– 235 N nominal crushing force
• Pretest: 15 minutes, 10 minutes contact time
– 500 grams of 2/4 mm granite
• Test: 30 minutes, 20 minutes contact time
– With granite gravel
according to the table

8. 100%
116%
131%
135%
153%
430
390
450
350
400
0
100
200
300
400
500
600
700
800
0%
20%
40%
60%
80%
100%
120%
140%
160%
A B C D E
Surfacehardness[HV5]
MasslosscomparedtosteelA
Up to 50 % difference in abrasion
wear performance
Average mass
losses [mg]
142 165 186 192 216

9. Tempered martensite with
untempered white martensite
A
B
C
D
20 µm
E

10. High-stress abrasive wear
EA
In general, the
more scratches
on the wear
surface, the
larger the mass
loss.
Wear mechanism
for scracthes:
two-body
abrasion

11. Surface characterization with
optical profilometer
• Estimated
average thickness
of the removed
material was
between 20 and
30 µm
• Deepest
scratches were
about 50-60 µm
deep
Optical profilometer image of steel C

12. Differences in wear surface
deformations
C
BA
E

13. Chemical compositions
• Hardenability
– Carbon
– Molybdenum (+Nickel)
– Boron
• Martensite formation
– Total amount of alloying
elements
– Amount of aluminum
and nickel
Steel A B C E
C 0.16 0.15 0.15 0.14
Si 0.4 0.28 0.22 0.38
Cr 0.14 0.37 0.41 0.46
Ni 0.04 0.07 0.09 0.04
Mo 0.15 0.1 0.01 0
Al 0.034 0.031 0.1 0.025
N 0.005 0.006 0.005 0.007
B 0.003 0.001 0.002 0.002
∑ 2.349 2.013 2.4 2.519
Chemical composition (wt%)
Steel D is removed due to possible manufacturing
faults

14. Concluding remarks
• Marked differences between the 400 HB grade
quenched steels in the wear performance
• Chemical composition: hardenability,
martensite formation and self temperability
• Microstructure: grain size and amount of
tempered martensite and white martensite
• Wear process: abrasive cutting
• Surface deformation: hardenability and self
temperability (a localized ‘requench’ process)

15. Thank you for your attention!
Niko Ojala
Research Scientist, PhD student
Tampere University of Technology
Department of Materials Science, Tampere Wear Center
P.O.Box 589, FI-33101 Tampere, Finland
phone: +358 50 317 4516
email: niko.ojala@tut.fi
www.tut.fi/twc/en
Acknowledgements