Versatile slurry and dry erosion testing is possible with the high speed slurry-pot tester at Tampere Wear Center. The tester enables an application oriented approach to the wear testing as sample type and shape as well as the wear environment can be selected with broad freedom.
This presentation was presented in the annual seminar of the Tampere Wear Center, titled as 'Hard rock tribology' this year. The seminar had some 80+ international participants.
Hard rock tribology seminar - slurry and dry erosion wear testing
1. Slurry and dry erosion of
wear resistant steels
Niko Ojala
Hard Rock Tribology Course and Seminar
Tampere University of Technology
November 4th – 5th 2014
2. 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
3. Objectives
• New versatile and application oriented test
method
• Powerful wear tester
• Possibility to test many material types
4. Overview to topics
1) The wear tester
2) Slurry and dry erosion testing
3) Wear results
5. 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]
Sample levels
One or two samples on one level
0-5 L1 L2 L3 L4
5-10 L4 L1 L2 L3
10-15 L3 L4 L1 L2
15-20 L2 L3 L4 L1
6. 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
protection
35 x 35 x 1-10 mm
Other profiles height <40 mm
Rotating
95 mm
radius, max
7. • 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
9. 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…
10. 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
13. 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
16. Slurry and dry erosion
• Both methods can yield high wear rates
• For comparison the wear rates below are
calculated for nominal wear areas
3500
3000
2500
2000
1500
1000
500
0
250 rpm
2 minutes
500 rpm
2 minutes
1000 rpm
2 minutes
Wear rate [g/h m2]
Dry-pot
S355 400HB 500HB
2500
2000
1500
1000
500
0
Slurry-pot
S355 400HB 500HB
Sample level 1 Sample level 2
Wear rate [g/h m2]
5 minutes at 1500 rpm
17. 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.
18. Acknowledgements
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
Notas do Editor
Motivation for my study is that in real life in industrial mineral handling related operations, the particle sizes can easily be large.
For heavy duty slurry erosion applications normally up to some centimeters at least.
Still the wide research in the field is done with really small particles, normally under 1 mm. So in my PhD studies I’m concentrated on large particle wear.
(large particles and/or high speeds -> wear rate)
The pin mill type slurry-pot wear tester was introduced in the last years NordTrib. It is based on the pin mill sample configuration, shown in this cross-section picture. For these tests I used both half- and full-length samples. Full-length means that one sample goes through the central shaft as with half-lenght samples there is two separate samples on one sample level. Also sample rotation test method was used. The method is presented in this table, and means that the test is composed of four parts and for every parts the sample positions, i.e. levels, is changed. This is for getting the final deviation of the results small.
Large particles in contrast to earlier studies (<1 mm)
In future work this equipment will be used to test slurry-erosion resistance of different types of materials in variable slurry conditions, including concentration, particle size, and abrasive type. Furthermore the equipment will be used for characterization of different minerals by their erosiveness.
Here is two close-ups for the largest concentration. It greates smaller abrasive scars than the smaller concentration, mostly by the higher comminution and higher erosion component. Other image shows embedded granite particle. As mentioned, higher concentration induced also more embedding.
Tulokset jäi nyt paperille, kun en ehtiny niitä kirjaan koneelle… Mutta menetelmä toimii.
Tein testin 2min pätkissä 250, 500 ja 1000 rpm. Massahäviö S355 näytteistä oli ihan huomattava, varsinkin suuremmilla nopeuksilla.
Näytteet ei lämmenny, kuten kuivalla kvartsihiekalla käy, joten olosuhteet pysy ”luonnollisina”. Yli 1000 rpm nopeuksia ei varmaan kannata edes käyttää, kun se vastaa jo noin 40 km/h nopeutta (näytteen kärjessä) puskutraktorille joka tunkee kauhansa sorakasaan. ;)
Näytteet kulu päältä, alta ja tietenkin etureunasta. Kesän jälkeen suunnittelin tekeväni testejä Raex 400 ja 500 näytteillä ja niihin vois koneistaa esim. kahden eri kulman viisteen etureunaan.
Tulokset jäi nyt paperille, kun en ehtiny niitä kirjaan koneelle… Mutta menetelmä toimii.
Tein testin 2min pätkissä 250, 500 ja 1000 rpm. Massahäviö S355 näytteistä oli ihan huomattava, varsinkin suuremmilla nopeuksilla.
Näytteet ei lämmenny, kuten kuivalla kvartsihiekalla käy, joten olosuhteet pysy ”luonnollisina”. Yli 1000 rpm nopeuksia ei varmaan kannata edes käyttää, kun se vastaa jo noin 40 km/h nopeutta (näytteen kärjessä) puskutraktorille joka tunkee kauhansa sorakasaan. ;)
Näytteet kulu päältä, alta ja tietenkin etureunasta. Kesän jälkeen suunnittelin tekeväni testejä Raex 400 ja 500 näytteillä ja niihin vois koneistaa esim. kahden eri kulman viisteen etureunaan.