Hard rock tribology seminar - slurry and dry erosion wear testing
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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.
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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
- 8. 2) Slurry and dry erosion testing 3) Wear results
- 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
- 11. One tester, many applications…
- 12. 3) Wear results
- 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
- 14. 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
- 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
Editor's Notes
- 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.