Abrasion wear performance of quenched wear resistant steels

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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.

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Abrasion wear performance of quenched wear resistant steels

  1. 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. 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. 3. Overview to topics 1) Materials and methods 2) Results 3) Discussion
  4. 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. 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
  6. 6. 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
  7. 7. 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
  8. 8. Tempered martensite with untempered white martensite A B C D 20 µm E
  9. 9. 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
  10. 10. 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
  11. 11. Differences in wear surface deformations C BA E
  12. 12. 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
  13. 13. 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)
  14. 14. 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

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