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 Elongationat 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 depth: lt = 39 mm Coolant pressure: pKSS = 170 bar
100 0,05 B f F M M Chip formation F N f B Nm vc = 20 m/min vc = 30 m/min 60 0,03 force torque
40 0,02 m µ
Feed 20 0,01 f3= 0 0 Drilling Tool breakage
f 390 l Tool breakage mm 234 length f = 5 µm f5= 156 78 Drilling Drilling
0 m µ f7= 5 mm
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 depth: lt = 39 mm Coolant pressure: pKSS = 170 bar
Chip formation
vc = 20 m/min vc = 30 m/min m µ f3= f = 5 µm f5= Bottom side Upper side m µ f7= 5 mm
0,2 mm Institute of Machining Technology Kirschner Performance of Single-Lip Deep Hole Drills
Tool: SLD Ø 1,3 mm Cutting speed: vc = 30 m/min Tip design: Varied Feed rate: f = 5 µm Workpiece: Inconel718 Coolant: Mineral oil
Drilling depth: lt = 39 mm Coolant pressure: pKSS = 170 bar 100 f
F N 60 force 40
Feed 20 0 Standard SA 1 SA 2 SA 3 SA 4
B 0,05 M Nm 0,03 torque 0,02 0,01 Drilling Drilling 0 Standard SA 1 SA 2 SA 3 SA 4 Tool tip design 5 mm 0,3 mm Institute of Machining Technology Kirschner Performance of Single-Lip Deep Hole Drills
Tool: SLD Ø 1,3 mm Cutting speed: vc = 30 m/min Tip design: Varied Feed rate: f = 5 µm Workpiece: Inconel718 Coolant: Mineral oil
Drilling depth: lt = 39 mm Coolant pressure: pKSS = 170 bar
5 mm 0,3 mm Institute of Machining Technology Kirschner 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 Cutting Edge Radius and Form-Factor
Source: C.-F. Wyen (2011)
Source: Denkena, B.; Biermann, D.: Cutting edge geometries. CIRP Annals - Manufacturing Technology, 63, 2014, 631–653.
Institute of Machining Technology Wolf Different Process Designs for Wet Abrasive Jet Machining
Institute of Machining Technology Wolf Process Parameters Using Robot Guided Wet Abrasive Jet Machining
Institute of Machining Technology Wolf Influence of Jet Angle on the Affected Area of the Wedge
Institute of Machining Technology Wolf Influence of Jet Angle on Resulting Form- Factor
Institute of Machining Technology Wolf Influence of Form-Factor on the Tool Performence
3.0 75
f kN
F µm
2.0 VB
flank 45 force
1.5 of land 30 1.0 Feed Feed wear 0.5 Width 15 0 0 0 4 8 12 16 m 24 0 4 8 12 16 m 24 Drilling length lf Drilling length lf
15 Flank face Nm b
M 9 Rake face 6 100 µm Torque 3 0 K < 1 0 4 8 12 16 m 24 K ≈ 1 Drilling length lf K > 1
Tool: Cemented carbide drill Rounding: S = constant Feed: f = 0.15 mm Cutting material: TiAlN Drilling depth: lt = 42.5 mm Drilling length: lf = 22.5 m Diameter: d = 8.5 mm Cutting speed: vc = 110 m/min Material: 42CrMo4 Institute of Machining Technology Wolf 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
Guide pad 1
Guide pad 2
Source: Kaiser Maschinenbau Source: Baker Hughes Guide pad 3
Application of TiN-coated guide pads
• Material: X5CrNi18-10 GP1 Material-element: Cr Undamaged coating • TiN-coated guide pads • Adhesive wear • Significant guide pad wear after GP2 a drilling length of lf = 250 mm
Tribological modification of the GP3 coating of the guide pads is Substrate: W necessary
5 mm 1 mm Institute of Machining Technology Abrahams Friction Coefficient with Respect to the Guide Pad Coating
Material: C60, X5CrNi18-10 Feed rate f: 0.2 mm
Guide pad radius rgp: 20 mm Cutting speed vc: 50 m/min Coating: Varied Indenation depth ap: 0.05 mm ta-C-hardness Hc: 68.4 GPa Lubricant: Emulsion, 6 %
C60 X5CrNi18-10 0,6 0,6 Uncoated (grinded) TiN (finished) µ - - ta-C (finished)
0,4 0,4
0,3 0,3 coefficient
0,2 0,2
Friction 0,1 0,1
0 0 0 25 50 75 100 125 s 175 2mm 0 25 50 75 100 125 s 175 2mm
Time Time Institute of Machining Technology Abrahams Wear Analysis of Modified and Conventional Guide Pads
Guide pad 1
Guide pad 2
Guide pad 3
X5CrNi18-10 0.2 mm Bore hole quality Material: f: 6 30°-chamfer 80 m/min Guide pad-shape: vc: Rz Coating: Varied ld: 0.25 m µm 4 GP1 GP2 GP3 3 Conventional GP Roughness (TiN-coated) 2
Modified GP 1
(ta-C-coated; Surface 0 microfinished) 5 mm TiN ta-C Coating Institute of Machining Technology Abrahams 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 Conclusion
. The high strength of bainitic steels had a negative influence on tool life time in comparison to the well known quenched and tempered steel 42CrMo4+QT. A tool and cutting parameter optimisation was executed in order to compensate this effect.
. Machinability of hardened tool steels with small cemented carbide tools (d < 1 mm) is possible. Suitable tool design and cutting parameters are important for a successful micromilling process.
. An advantegeous chip form is the essential requirement for a stable and productive deep hole drilling process. For this purpose a decided adjustment of the cutting data as well as the cutting edge design becomes inevitable when machining Inconel718.
. Abrasive jet machining is suitable for coating pre- and post-treatment of cemented carbide twist drill. By using a tailored process control, an increase in tool performance is attainable.
. The BTA deep hole drilling of austenitic steels leads to a strong adhesive wear of the guide pads. A friction reducing ta-C-coating effects a higher wear resistance of the pads and an increased surface quality of the machined bore hole.
Institute of Machining Technology Conclusion
Macro shape
Coating Stabilization Micro shape
The development of cemented carbide and its suitable treatment increases the performance of this extraordinary cutting material and makes up an important key factor for the Wear reduction Surface Quality solution of future machining tasks.
Cutting edge preparation Cutting edge
Process reliability Chip formation
Institute of Machining Technology Thank you for your attention!
The investigations were supported by
The results presented here are from the research project IGN 16939 N. Funding was provided by the German Federal Ministry of Economics and Technology via the German Federation of Industrial Cooperative Research Associations „Otto von Guericke“ (AiF) in the program to encourage the industrial community research by a resolution of the German Bundestag and the Steel Forming Research Society (FSV). The final report can be ordered from the FSV, Goldene Pforte 1, 58093 Hagen, Germany.
This work was supported by the German Research Foundation (DFG) within the scope of the Transregional Collaborative Research Center on Sheet-Bulk Metal Forming (CRC/TR73) in subproject B2.
The authors acknowledge funding from the German Research Foundation (DFG) for the project „Entwicklung von tribologisch optimierten Führungsleisten für das Tiefbohren“ (GZ: BI 498/64-1).
The authors acknowledge funding from the German Research Foundation (DFG) for the project „Hochgeschwindigkeitsspanbildungsanalyse für das Tiefbohren kleiner Durchmesser von hochfesten und schwer zerspanbaren Werkstoffen “ (GZ: BI 498/67-1).
Institute of Machining Technology Thank you for your attention!
Prof. Dr.-Ing. Dirk Biermann [email protected]
Dipl.-Ing. Dipl. Wirt.-Ing. Dipl.-Ing. Dipl.-Ing. Maximilian Metzger, Dipl. Wirt.-Ing. Hendrik Abrahams Henning Hartmann Marko Kirschner Eugen Krebs M.Sc. Mark Wolf [email protected] [email protected] [email protected] [email protected] [email protected] [email protected] Institute of Machining Technology