Wear of cemented tungsten carbide percussive drill–bit inserts: Laboratory and field study
| Autor: | Afaf Saai, Mikko Hokka, Veli-Tapani Kuokkala, Anna From, Alexandre Kane, Maria Bengtsson, Carina Oelgardt, Dmitry Tkalich, Vladislav A. Yastrebov, Charlie C. Li |
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| Přispěvatelé: | Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU), Centre des Matériaux (MAT), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SINTEF Materials and Chemistry, Tampere University of Technology [Tampere] (TUT) |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Split Hopkinson pressure bar Rotary–percussive drilling 02 engineering and technology Surface finish Impact abrasion SEM Abrasion (geology) chemistry.chemical_compound Wear 0203 mechanical engineering Tungsten carbide Materials Chemistry Drill bit Cemented tungsten carbide Surface deterioration mechanisms Volume loss 020502 materials Metallurgy Surfaces and Interfaces Split-Hopkinson pressure bar Condensed Matter Physics Microstructure Roughness Grain size Surfaces Coatings and Films 020303 mechanical engineering & transports 0205 materials engineering chemistry Mechanics of Materials [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] Contact area Sliding abrasion |
| Zdroj: | Wear Wear, Elsevier, 2017, 386-387, pp.106-117. ⟨10.1016/j.wear.2017.05.010⟩ |
| ISSN: | 0043-1648 |
| Popis: | International audience; Design of the drill–bit and selection of the Cemented Tungsten Carbide (CC) grade for drill–bit inserts are crucial for efficient percussive drilling. This study presents the results of an experimental campaign executed with the aim to identify the distinctive wear mechanisms and behaviour of different CC grades. Three laboratory and one full–scale drilling tests were performed using nine CC grades with different binder contents, binder chemical compositions, mean tungsten carbide (WC) grain sizes, and grain size distributions. Wear traces found on the drill–bit inserts after the full–scale drilling test show noticeable differences depending on their position on the drill–bit. Tensile forces present on the leading edge of the inserts due to the sliding contact with rock are suspected to play a significant role. Laboratory tests performed include: (i) single impact tests using a modified Split Hopkinson Pressure Bar (SHPB) apparatus, (ii) Abrasion Value (AV) rotating disk tests, and (iii) impact abrasion (LCPC) tests. Volume loss and shape change were used as macroscopic measures of wear. Greater volume losses were found for the grades with nickel–based binders compared to those with pure cobalt binder. The use of a narrower WC grain size distribution leads to lesser volume loss in drilling and AV tests. Surface analysis of the damaged microstructure was performed using scanning electron microscope. Distinct meso–scale (few dozens of WC grain sizes) patterns of damaged microstructure zones surrounded by the intact surface were found on the surfaces of specimens after single impact test. The pattern indicates the potential influence of a non–uniform contact due to the rock roughness and internal rock heterogeneities, which is supported by the study of the rock crater roughness. Size of such zones could be seen as a certain length–scale, which determines the insert–rock contact behaviour. A specific “peeling” mechanism of material removal was observed in the full–scale drilling test, where portion of the CC microstructure fused with the rock tribofilm gets removed when that tribofilm peels off. |
| Databáze: | OpenAIRE |
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