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Slurry and dry erosion of
wear resistant steels
Niko Ojala
Hard Rock Tribology Course and Seminar
Tampere University of Technology
November 4th – 5th 2014
Motivation
• In mining and mineral
processes particle sizes
can be up to several
centimeters
• But the erosion wear
research have been
often done with
under 1 mm particles
Objectives
• New versatile and application oriented test
method
• Powerful wear tester
• Possibility to test many material types
Overview to topics
1) The wear tester
2) Slurry and dry erosion testing
3) Wear results
High speed slurry-pot tester
• Samples in the pin mill configuration
– Four sample levels
– Different sample shapes and sizes
– Up to 20 m/s sample speed
– Up to 10 mm particle size
– Sample rotation test method
time [min]
0-5 L1 L2 L3 L4
5-10 L4 L1 L2 L3
10-15 L3 L4 L1 L2
15-20 L2 L3 L4 L1
One or two samples on one level
Sample levels
Versatile sample size & shape
Sample types and dimensions
Round profile Ø 18.5 & 26 mm
Square profile 15 x 15 mm
Plate sample 64 x 40 x 6-10 mm
Plate w/ edge
protection35 x 35 x 1-10 mm
Other profiles height <40 mm
Rotating
radius, max95 mm
• New high speed slurry-pot tester enables testing
– With high speeds, up to 20 m/s
– With large particle sizes, up to 10 mm
– In slurry and dry environments
– Of different materials with various sample profiles
– Of erosiveness (abrasivity) of different abrasives
10 mm
Summary
2) Slurry and dry erosion testing
3) Wear results
Slurry and dry erosion testing
• High speed slurry-pot can be used for testing:
– Slurry pumping/transportation
– Wear protection and liner materials in mineral
processes
– Drilling and excavation
– Different materials:
• Steels, cast irons, rubbers, polymers, composites,
thin and thick coatings, surface treated materials,
hard weld overlays…
Slurry and dry erosion testing
Slurry-pot Dry-pot
Wear mechanisms slurry-erosion, abrasive
erosion
erosion, grinding
abrasion
Particle concentration 0-50 wt.% 100 wt.%
Sample angle (currently) ±45°, 90° 0°
Sample tip speed up to 20 m/s up to 10 m/s
Test time (typical) 4 x 5-20 minutes with
sample rotation
4 x 2-5 minutes
One tester, many applications…
3) Wear results
A structural steel vs a wear resistant steel after the tests with 9 wt% 8/10 mm granite slurry.
Wear surface of a wear resistant steel
Wear surfaces
Dry grinding abrasion
• Wear resistant steels tested with oversized
granite (12/14 mm).
• Short samples (45 mm), 5 m/s, 2 minutes
Upper surface Lower surface
Dry grinding abrasion
• Both methods can yield high wear rates
• For comparison the wear rates below are
calculated for nominal wear areas
0
500
1000
1500
2000
2500
3000
3500
250 rpm2 minutes
500 rpm2 minutes
1000 rpm2 minutes
We
ar
rate
[g
/h m
2]
Dry-pot
S355 400HB 500HB
0
500
1000
1500
2000
2500
Sample level 1 Sample level 2
We
ar
rate
[g
/h m
2]
5 minutes at 1500 rpm
Slurry-pot
S355 400HB 500HB
Slurry and dry erosion
Conclusions
• The high speed slurry-pot is application
oriented erosion wear tester.
• Sample shape and size can be adjusted for
the needs of the real life application.
• Both slurry and dry erosion testing is
possible.
• Wear environment can be chosen from mild
erosion to severe abrasive erosion or
grinding abrasion.
Thank you for your attention!
Niko Ojala
Research Scientist, Doctoral 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
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