Cemented Carbide as an Important Enabler for Machining Developments WORLD PM2016 Congress and Exhibtion 90 Years of Cemented Carbide – Past, Present and Future October 13th, 2016 Hamburg Prof. Dr.-Ing. Dirk Biermann Dipl.-Ing. Hendrik Abrahams Dipl. Wirt.-Ing. Henning Hartmann Dipl.-Ing. Marko Kirschner Dipl.-Ing. Eugen Krebs Maximilian Metzger, M.Sc. Dipl. Wirt.-Ing. Mark Wolf Institute of Machining Technology Prof. Dr.-Ing. Dirk Biermann TU Dortmund University http://www.isf.de Institut für Spanende Fertigung Outline . Historical Review of Cemented Carbide as a Cutting Tool Material . Cemented Carbide as an Important Enabler for Machining Developments . Turning of a High Strength Bainitic Steel . Micromilling of Hardened High-Speed Steels . Small Diameter Deep Hole Drilling . Pre- and Post-Treatment of Twist Drills . Tribological Optimization of the Coating of Guide Pads for the BTA Deep Hole Drilling . Conclusion Institute of Machining Technology Outline . Historical Review of Cemented Carbide as a Cutting Tool Material . Cemented Carbide as an Important Enabler for Machining Developments . Turning of a High Strength Bainitic Steel . Micromilling of Hardened High-Speed Steels . Small Diameter Deep Hole Drilling . Pre- and Post-Treatment of Twist Drills . Tribological Optimization of the Coating of Guide Pads for the BTA Deep Hole Drilling . Conclusion Institute of Machining Technology Historical Review of Cemented Carbide as a Cutting Tool Material Source: Seco – I cut . The beginning of cemented carbide is connected to the light bulb production . Post-war production: Difficulties to find the diamonds required to draw the tungsten wire used in light bulb filaments . The German Osram Group invented a new material: Tungsten carbide with Cobalt as a bonding agent . Laboratory Director Schröter took responsibility for the invention patent application 27.07.1922 start of modern cemented carbide Source: Kolaska, H.: Hartmetall – heute, gestern und morgen . Krupp Group took over the manufacture of hard metal from Osram . Krupp presents Widia-N (Wie Diamant, like diamond) at “Leipzig Expo” (Leipziger Frühjahrsmesse) in 1927 Institute of Machining Technology Historical Review of Cemented Carbide as a Cutting Tool Material Increase of cutting speed Total effort Turning steel: Effort for turning 1000 kg of steel Rm = 490 MPa, ap = 5 mm, f = 1 mm/rev with strength of Rm = 880 Mpa (1940) Source: Amman, E.: Die Entwicklung und technische Institute of Machining Technology Bedeutung der Hartmetalle Historical Review of Cemented Carbide as a Cutting Tool Material . “Magnus, you have to invent something better than Widia” Fagersta Works Manager Axel Fornander to Research Manager Magnus Tigerschiöld (1929) . Widia-X, launched in 1931, contained not only tungsten carbide and cobalt but also titanium carbide . 1950s: Indexable inserts break through . 1969: Sandvik patented a titanium carbide-coated indexable insert with an astounding performance Source: Sarin, V.: Introduction to Hardmetals Institute of Machining Technology Outline . Historical Review of Cemented Carbide as a Cutting Tool Material . Cemented Carbide as an Important Enabler for Machining Developments . Turning of a High Strength Bainitic Steel . Micromilling of Hardened High-Speed Steels . Small Diameter Deep Hole Drilling . Pre- and Post-Treatment of Twist Drills . Tribological Optimization of the Coating of Guide Pads for the BTA Deep Hole Drilling . Conclusion Institute of Machining Technology Motivation for the Use of Bainitic Steels Potentials and applications Material properties 42CrMo4+QT 20MnCrMo7+BY Gerhard Barth 1400 A5 70 MPa/ Z/ % HV30 Hardness / 1000 area 50 m fracture of R Bosch Oldi&Co. 800 40 600 30 Forging QT-Steel 400 20 strength 200 Reduction 10 Elongation at 0 0 Rm HV30 Z A5 Heat treatment ThyssenKrupp Tensile Challenges Bainite Gröditzer Institute of Machining Technology Machining CERATIZIT Hartmann Machining Comparison between a Quenched and Tempered Steel and a High Strength Bainitic Steel Varied v = 200 m/min Material: Cutting speed: c Fc Tool: CNMG120404 - HC-P15 Feed rate: f = 0.3 mm Ff Cooling: Lubricant Cutting depth: ap = 1 mm Cutting time: tc = 9…18 min Fp m 0,2 Quenched and tempered steel Bainitic Steel R 1400 Rp 42CrMo4+QT (304 HV30) 20MnCrMo7+BY (374 HV30) MPa p 1000 F 800 1000 600 and strength f strength 400 N , F force 200 c F 600 0 Yield Tensile Rm Rp0,2 400 200 A5 Z Resultant 70 0 % 0 3 6 9 12 min 18 0 3 6 9 12 min 18 area components 50 ´ Cutting time tc Cutting time tc fracture of 40 30 VBmax = 178 µm VBmax = 327 µm 20 10 0 Reduction A5 Z Elongation at Institute of Machining Technology Hartmann Influence of the Cutting Material on Tool Lifetime Material: 20MnCrMo7+BY Cutting speed: vc = 200 m/min Tool: CNMG120408 - HC-P15 Feed rate: f = 0.3 mm - HC-P05 Cutting depth: ap = 1 mm Cooling: Lubricant Cutting time: tc = 12…18 min Fc Ff Fp p HC-P15 HC-P05 F 900 and N f , F force 600 c F 450 300 Resultant 150 0 componetns 0 3 6 9 12 min 18 0 3 6 9 12 min 18 Cutting time tc Cutting time tc VBmax = 348 µm VBmax = 287 µm Institute of Machining Technology Hartmann Outline . Historical Review of Cemented Carbide as a Cutting Tool Material . Cemented Carbide as an Important Enabler for Machining Developments . Turning of a High Strength Bainitic Steel . Micromilling of Hardened High-Speed Steels . Small Diameter Deep Hole Drilling . Pre- and Post-Treatment of Twist Drills . Tribological Optimization of the Coating of Guide Pads for the BTA Deep Hole Drilling . Conclusion Institute of Machining Technology Motivation und Micromilling Hardened tool steel Micromilling . ≤ Milling tools Punching tool Tool diameter d 1 mm . Smallest comercial available diameter d = 0.01 mm Advantages . High manufacturing accuracy and quality Reference: NAWA Präzisionstechnik GmbH Reference: Gustav . Manufacturing of complex tools and dies Seeger Stanzwerkzeuge with filigree structures with high process reliability Dies for Sheet-Bulk . Manufacturing of complex structures with Metal Forming high aspect ratios usind five-axis machining . Different materials . Negligible thermal effects at the subsurface Micromilling tools Tool www.tr-73.de Filigree form elements . Gear . Open or closed carrier ∅1 mm ∅0.03 mm Human hair Institute of Machining Technology ∅0.2 mm Krebs Tool Steels Cold-work tool steel High speed steel High speed steel (PM) 1.2379 (X153CrMoV12) 1.3343 (S6-5-2) 1.3395 (ASP2023) Carbide accumulation 50 µm Carbide 50 µm Carbide 50 µm Material properties High carbide ratio . High toughness X153CrMoV12 . Inhomogeneous distribution . High compressive strength . Grain size: 5 bis 30 µm . High-temperature strength S 6-5-2 . Homogeneous distribution . Excellent abrasion resistance . Grain size : 1 bis 10 µm . Hardness ≤ 65 HRC ASP 2023 . Homogeneous distribution . Grain size : 1 bis 3 µm Institute of Machining Technology Krebs Machinability of Hardened High-Speed Steels (> 60 HRC) with Small Tools Challenges . High hardness of workpiece . Low difference in hardness High process forces between tool and workpiece High tool wear S6-5-2 TiAl6V4 X5CrNi18-10 . Mechanical process 10 591 % N8 Hardened high Cemented Micromilling 6 speed steel carbide tools 424 % 4 Process force Process 2 > 60 HRC > 70 HRC 0 3 20 Source: LWT Feed per tooth fz 50 µm 50 µm Tool: End-milling cutter, d = 0,5 mm, z = 2 Workpiece: var. Cutting speed: vc = 100 m/min Feed per tooth: fz = 3 - 20 µm Depth of cut: ap = 0,003 mm Strategy: Slot milling, End-milling cutter, d = 0,3 mm Ball-end milling cutter, d = 0,2 mm Down milling, dry Institute of Machining Technology Krebs Surface Quality when Using Suitable Tool-Design and Process Parameters 3D measurement Tool: end-milling cutter, 120 d = 1 mm, z = 2 : HC (ultra-fine height Substrate nm grained) 40 Coating: TiAlN 200 µm Workpiece: ASP2023 (63 HRC) Structure 0 Cutting speed: vc = 120 m/min In feed direction Depth of cut: ap = 0,025 mm Rz = 92,6 ±3,5 nm Width of cut: ae = 0,1 mm 10 mm Feed per tooth: fz = 0,025 mm Crosswise to feed direction Strategy: down milling, dry ± Micromilled surface Rz = 98,1 3,9 nm Machining time:approx. 4 min Suitable tool geometry . Robust cutting edge . Short cutting lenght . Rake angle γ = 0 ° . Helical angle λ = 0 ° . Sharp cutting edge (cutting 0,5 mm edge rounding S < 2 µm) . Good coating adhesion Institute of Machining Technology � Krebs Outline . Historical Review of Cemented Carbide as a Cutting Tool Material . Cemented Carbide as an Important Enabler for Machining Developments . Turning of a High Strength Bainitic Steel . Micromilling of Hardened High-Speed Steels . Small Diameter Deep Hole Drilling . Pre- and Post-Treatment of Twist Drills . Tribological Optimization of the Coating of Guide Pads for the BTA Deep Hole Drilling . Conclusion Institute of Machining Technology Introduction and Motivation Application fields of small diameter deep hole drilling • Automotive • Medical technology • Aerospace • Petrochemical industry • Food industry [www.bosch-presse.de] [www.synthes.com/ [www.astrium.eads.net] [http://supertechperformance.com] www.normed-online.com] Challenges of the Process • Low tool rigidities 10 mm • Adjustable feed rates are limited • Unfavourable ratio of cutting edge rounding and undeformed chip thicknesses • Difficulties of chip removal • Spontaneous tool failure 250 µm 200 x 250 µm Institute of Machining Technology Kirschner Performance of Single-Lip Deep Hole Drills Tool: SLD Ø 1,3 mm (Std.) Cutting speed: Varied Contour: Shape G Feed rate: Varied Workpiece: Inconel718 Coolant: Mineral oil Drilling