Presentation given at Hard rock tribology seminar 4-5.11.2014 at Tampere University of Technology, Finland Information about the equiopment can be found at http://www.tut.fi/twc/en Articles including measurement data can be found at https://www.researchgate.net/profile/Vilma_Ratia

1. Abrasive and impact-abrasive wear testing of steels for mining, transporting, and mineral processing
Hard rock tribology seminar
4.11.2014
Vilma Ratia Tampere University of Technology, Tampere Wear Center,
Tampere, Finland

2. Contents
•Wear – what is it?
What are wear resistant steels?
•How can wear resistance be controllably measured?
•How wear is shown in steels?
•Which factors affect wear of steels?

3. The durability of machinery in raw materials extraction and processing is increasing in importance
geosyntheticsmagazine.com
ruukki.com
ruukki.com

4. 0.142
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Surface hardness [HV5]
Mass loss [g]
Wear resistant steels have higher
strength and hardness than
conventional structural steels
• Commonly graded
according to hardness
in Brinell scale:
400HB, 500HB, 600HB
• Tensile strength
typically 1200-1600
MPa
• Notch impact energy at
-40C typically 30 J/cm2
• Microstructure often
martensitic, but bainite,
ferrite, pearlite and
austenite are also
possible
ruukki.com
N. Ojala et al. WTC 2013 & Wear 317(2014)225-232

5. Wear resistant steels can be used in a wide range of applications
Examples of applications:
•Agriculture
(harvesters, ploughs)
•Earth moving
(tippers, excavator buckets)
•Forestry
(frost and rock rippers, stump processors)
•Mining
(wheel loader buckets, stock pile conveyors, sieves, conveyor belt hoppers)
johndeeredistributor.fi
deere.fi
ruukki.com
sandviktamrock.fi

6. •Impeller (samples) 700 rpm
•Tumbler 30 rpm
•900 g of granite(10-12,5 mm)/15 min
•Altogether about 3-22 kg
•Sample size 75 x 25 x 10 mm
•Sample angle 30°, 60° or 90°
•Test duration 45-360 min
Impeller-tumbler simulates wear in hammer mills, silos, loading of tippers
•Impeller-tumbler combines impacts and abrasive wear
Wear testing enables the evaluating of materials’ wear performance in controlled conditions
metso.com
ruukki.com

8. Uniaxial crusher simulates wear in crushers and tippers while transport
•Crushing of gravel with high force up to 86 kN
•Fresh granite (4-6,3 mm) for each crush
•Typical test duration 1000 compressions
Sample
Abrasive cup
Supply tube
ruukki.com

9. Crushing pin-on-disc simulates wear in crushers and unloading of tippers
•Abrasives as loose particles
•500 g in a test
•Used force 200 N
•Pin diameter 36 mm
•Disc diameter 160 mm
•Test duration 30 minutes (240 crushes)
•Running-in of 20 minutes
ruukki.com

10. 10

11. Steels and abrasives have many kind of interactions
•Deformation:
–Ploughing
–Wedge formation
•Embedding of abrasives
•Indentations
•Fatigue due to subsequent impacts
•Chip formation
•Cutting

12. The harder steels have clearer scratches and less abrasive remnants
S355
500HB
S355
500HB

13. Hardening can enhance wear resistance
•Work hardening takes place in impacts, but also in high-stress abrasion
•The tendency of work hardening is beneficial, unless it makes the top layer brittle
400HB
650HB
V.Ratia et al. Wear 301(2013)94-101

14. Depending on the contact, hardness may have a different role
V. Ratia et al. Tribology Online 8(2013)152-161

15. Abrasive properties affect the wear mechanism
•Abrasiveness, crushability, toughness, hardness etc.
•Size, size distribution and shape
Abraded with quartzite: Hardness 1200 HV, crushability 74%, abrasiveness 1840g/t
Abraded with tonalite: Hardness 960 HV,
crushability 18%, abrasiveness 1460g/t

16. WANTED: Wear resistant steels
•High hardness and strenght
•Good impact toughness and ductility
•Work hardening
•Adequate machinability, weldability etc.
•Decent producing costs
400HB
650HB
500HB

17. Thank you for your attention!
vilma.ratia@tut.fi
FIMECC BSA