Erosive Wear Testing of Laser Clad and HVOF Coatings for Drilling in Mining

Tuesday, May 28, 2019: 15:30
Annex Hall/F203 (Pacifico Yokohama)
Dr. Christiane Schulz , University of South Australia, Mawson Lakes, Australia
Dr. Thomas Schlaefer , LaserBond Ltd, Cavan, Australia
Dr. Eric Charrault , University of South Australia, Mawson Lakes, Australia
Dr. Colin Hall , University of South Australia, Mawson Lakes, Australia
Drilling is a major cost factor to mining operations (exploration, drill and blast operations) and wear of components is a significant driver of drilling costs. For drilling, especially in hard rocks, rotary drills do not deliver satisfactory results, Down-the-Hole (DTH) hammers or Reverse Circulation (RC) hammers are used. These drills break the rock through repetitive impact. Cuttings are removed via a high velocity air stream. The main wear mechanism for these hammers was found to be erosion.

To combat erosive wear laser clad coatings with a Ni-matrix and different sized fused tungsten carbides FTC (WC/W2C) (angular and spherical) and monocrystalline WC were developed. Moreover, hard Fe-based HVOF coatings were investigated and a wear-resistant steel served as a reference.

An erosion testing apparatus which follows ASTM G76 was developed. Testing was carried out from 15-90⁰ in 15⁰ steps for all materials. Coating performance was assessed via volume loss, obtained using 3D profilometry. At low angles the more brittle materials lost significantly less volume but at a 90⁰ angle the wear resistant steel performs almost as well as a hard phase loaded coating. Laser clad coatings with spherical FTC showed overall a better performance than coatings with angular FTC.

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