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On the Nature of Cemented Carbide Wear in Rock Drilling

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On the Nature of Cemented Carbide Wear in Rock Drilling Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 964 On the Nature of Cemented Carbide Wear in Rock Drilling BY ULRIK BESTE ACTA UNIVERSITATIS UPSALIENSIS UPPSALA 2004 !""# $"%$& ' ' ' ( ) * + +) , ) !""#) - . ' / / 0 1 2 ) 3 ) 45#) # ) ) 6,. 4$7&&#7&4847" 0/9/ ' + ) * : ' ;' 0/7 < ;' / < ' 2 ) * + ' '' 2 ) * ' + ' ' = 27 ) 3 ' 2 + ' + ) * ' ) * '' ' ' + *> + ) + : ' + 2 ? ' ' ) 6 + ' 2 + ' ' ' + ) @ + ' + '' 2 '' 2 ' ) ' 2 ' 2 ' 2 + + ' + ' 2 ) + 2 2 ! " # " !$ %&'" " #()%* +* " A 2 , !""# 6. $$"#7!8!B 6,. 4$7&&#7&4847" % %%% 7#!!8 ; %99 )2)9 C D % %%% 7#!!8< To… …my great surprise. List of Papers included in the thesis I Micro scale hardness distribution of rock types related to rock drill wear. U. Beste and S. Jacobson, Wear 254 (2003), Issue 11, p. 1147-1154. II Micro scratch evaluation of rock types – a means to comprehend rock drill wear, U. Beste, A. Lundvall, S. Jacobson, Tribology International (Feb 2004), vol. 37, Issue 2, p. 203-210 III Friction between a cemented carbide rock drill button and different rock types, U. Beste and S. Jacobson, Wear 253 (2002), p. 1219-1221. IV Pressure induced modification of a cemented carbide, U. Beste, H. Engqvist and S. Jacobson. Oral presentation at the 15th Int. Plansee Seminar, Austria, 28 May-1 June 2001. (Vol. 2 p. 685-697). Also highlighted in Metal Powder Report vol. 57, p 34 (2002). V Surface damage on cemented carbide rock drill buttons, U. Beste, T. Hartzell, H. Engqvist and N. Axén, Wear 249 (2001), p. 324-329. VI Homing cross sectioning – a technique to reveal weak zones in worn surfaces, U. Beste and S. Jacobson, In manuscript. VII Impact-induced rock penetration in cemented carbide rock drill buttons, U. Beste, S. Hogmark and S. Jacobson, In manuscript. VIII A new view of the deterioration and wear of cemented carbide rock drill buttons, U. Beste and S. Jacobson, In manuscript. The author’s contribution to the included papers I Planning, experiments, writing. II Planning, parts of experiments, writing. III Planning, experiments, writing. IV Parts of planning, parts of experiments, parts of analysis, writing. V Planning, major parts of experiments, analysis, writing. VI Planning, experiments, writing. VII Planning, analysis, parts of writing. VIII Planning, analysis, parts of writing. Contents 1. Introduction...............................................................................................11 1.1 Background ........................................................................................11 1.2 Rock drill history................................................................................11 2. Rock drilling .............................................................................................13 2.1 General rock drilling ..........................................................................13 2.2 Rotary - percussive drilling ................................................................13 2.3 Rotary crushing drilling .....................................................................15 2.4 Cutting................................................................................................16 3. Rock properties and characteristics...........................................................17 3.1 Basic mineral groups..........................................................................17 3.1.1 Quartz .........................................................................................18 3.1.2 Feldspar ......................................................................................18 3.1.3 Mica............................................................................................18 3.1.4 Hornblende .................................................................................19 3.1.5 Pyroxenes....................................................................................19 3.1.6. Carbonates, Oxides and Hydroxides..........................................19 3.2 Formation of rock...............................................................................20 3.3 Some common multi-mineral rock types ...........................................21 3.4 Hardness and mechanical properties of rock......................................21 3.4.1 Moh’s hardness scale..................................................................22 3.4.2 Micro scale hardness of rock [I] .................................................22 3.4.3 Micro friction of rock and their abrasive wear of CC [II] ..........25 3.4.4 Friction between a CC grade and different rock types [III]........29 3.4.5 Drillability rate index..................................................................31 4. Properties of Cemented Carbide ...............................................................33 4.1 Binder phase.......................................................................................33 4.2 Hard phase..........................................................................................33 4.3 Density ...............................................................................................34 4.4 Mean free path....................................................................................34 4.5 Thermal properties .............................................................................35 4.6 Cemented carbide hardness................................................................35 4.7 Fracture toughness..............................................................................36 4.8 Young’s modulus ...............................................................................36 4.9 Rock drill and hot rolling grades........................................................36 5. Wear and deterioration of cemented carbide ............................................37 5.1 The cemented carbide drill button meets the rock..............................37 5.2 What happens when a CC-button hits granite rock just a few times? 40 5.3 Wear of cemented carbide and pure WC............................................40 5.4 Rock drill wear – a literature review ..................................................42 5.5 Fatigue of cemented carbides.............................................................44 5.5.1 Cemented carbide fatigue – a literature review ..........................44 5.5.2 Pressure induced modification of a cemented carbide [IV]........45 5.5.3 The fatigue distribution in a CC rock drill button ......................46 5.6 Rock penetration into cemented carbide rock drill buttons................47 5.6.1 Homing cross sectioning [VI].....................................................47 5.6.2 Rock penetration into CC rock drill buttons [VII]......................48 5.7 Reptile skin formation........................................................................51 5.7.1 Reptile skin formation in magnetite drilling [V] ........................51 5.7.2 Thermal effects on wear – a literature review ............................54 5.7.4 A suggested new model for the reptile skin formation...............55 6. Summary...................................................................................................59 6.1 A new view of the wear of rock drill buttons [VIII] ..........................59 6.1.1 A first close look on a worn WC/Co rock drill button................59 6.1.2 Life limiting factors ....................................................................61 6.1.3 Mechanisms of deterioration ......................................................61 6.1.4 Mechanisms of removal..............................................................63 6.1.5 The new view..............................................................................65 7. Om hårdmetallslitage vid bergborrning (Summary in Swedish) ..............67 8. Acknowledgement ....................................................................................70 9. References.................................................................................................72 Preface (på Swedish) – Det låter svårt, brukar folk säga med bruten min, när man lite motvilligt svarat på frågan så vad jobbar du med då? Tjejer mer än killar. Det är lite svårare när man ska berätta varför man jobbar med det man gör. Kanske är förklaringen en bakgrund som liknar upplevelserna som professor Oliver Sacks skriver om i boken ”Morbror volfram”: Många av mina barndomsminnen handlar om metaller; redan från första början tycks dessa ha utövat en speciell makt över mig. De stack på ett iögonenfallande sätt av mot den övriga världens likformighet, genom sin skinande och skimrande beskaffenhet, sin silverglänsande prägel, sin släthet och sin vikt. De verkade kalla när man rörde vid dem, och de klingade när man slog på dem. Morbror Dave älskade tätheten hos den volfram han framställde, liksom dess motspänstighet och stora kemiska stabilitet. Han älskade att handskas med den – både som tråd och som stoft, men framförallt i form av massiva små stänger och tackor. Han smekte dem och vägde dem i sina händer. ”Det finns ingenting i hela världen som känns som sammanpressad
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