New tools and processes for improving machining of heat resistant alloys used in aerospace applications MACHERENA

Size: px

Start display at page:

Download "New tools and processes for improving machining of heat resistant alloys used in aerospace applications MACHERENA"

Dulcie Butler
5 years ago
Views:

1 New tools and processes for improving machining of heat resistant alloys used in aerospace applications MACHERENA P. Alonso, GEYCA, Spain Aeronautical Days 2006 Vienna, 20 June 2006

2 Objective Improvement of the machining processes of aeronautic heat resistant alloys by means of more efficient tools and processes Materials Fe-Ni Alloys. A-286 Ni Alloys. INCONEL 718, IN100 γ-tial Intermetallic Processes Milling Turning Drilling Means Surface technologies (nano-structured coatings) Design of tools High pressure coolant machining

3 Industrial Objectives - Reduction of production downtime - Reduction of machining time - Reduction of finishing time (better finished products) - Improved tool output/cost ratio Increase of machining productivity

4 Aeronautical Applications Jet engine components

low-pressure compressor high-pressure compressor

5 Titanium alloys Titanium- or nickelbased alloys Nickel-based alloys Nickel- or titaniumbased alloys fan low-pressure compressor high-pressure compressor high-pressure turbine medium-pressure turbine turbofan engine PW2037 (cutaway)

6 Turbine Vanes L P Turbine Cases

7 Valves Turbineblades Satellite nozzles

8 Consortium MACHERENA

9 Demands on the machining process Difficult to cut materials Fe-Ni Superalloys γ-tial Intermetallics Ni alloys Properties of difficult to cut materials: High heat resistance Low heat conductivity High ductility Brittleness... Build-up edges Adhesion Strain hardening... High thermal and mechanical loads on tool cutting edge Bad chip flow Damages to surface and subsurface Demands on processes: Decrease of mechanical and thermal loads on tool cutting edge

10 Decrease of mechanical and thermal loads on tool cutting edge Design of cutting tools Tool coating (nano-composite) High Pressure Cooling (150 bar)

11 Cutting tools design - Tool geometry: -Radial rake angle -Helix angle -Primary clearance angle -Primary clearance land width -Point angle (drills) -Point clearance angle (drills) -Edge preparation -Carbide grade

12 Tool parameters Variation of radial rake angle γ rad Variation of helix angle δ

13 Taguchi Roughing A Cutting length / mm EMT 210 EMT61 DK460UF Clear results for helix angle, clearance angle and carbide grade Radial Rake Helix Angle Primary Clearance Carbide Grade Biggest influence of helix angle Edge breakouts using big helix angle Low helix angle and big clearance angle preferable No clear result for the radial rake angle

14 IN100 FINISHING Best results for low helix and medium radial rake angles

15 Edge preparation MACHERENA -Increased cutting edge radius -Improved surface finish -Improved coating adhesion -Less microchipping at tool edges Before - But increased cutting forces After

16 Rough Mill for INCONEL 718 Efect of edge preparation: cutting edge radius of 10 µm appears as the most favourable value L 5µm = 1276 mm L 10µm = 1276 mm L 20µm = 1276 mm 5 µm (WZL) 10 µm (WZL) 20 µm (WZL)

17 Coatings - Requirements: -High hardness -Good toughness -Low material affinity -High thermal stability -Composite of a high strength amorphous phase as matrix (a-si 3 N 4 ) and hard transition metal-nitride nanocrystals: Ti 1-x Al x N/SiN y Cr 1-x Al x N/SiN y (plus lubricant film on top)

SiN y nc-altin or AlCrN SiN y Coating Nanocomposite PVD-coatings Nanocrystalline grains (Ti 1-x Al x Nor Cr 1-x Al x N) embedded into an amorphous matrix (SiN y )

18 SiN y nc-altin or AlCrN SiN y Coating Nanocomposite PVD-coatings Nanocrystalline grains (Ti 1-x Al x Nor Cr 1-x Al x N) embedded into an amorphous matrix (SiN y ) Monolayer or multilayer coatings Extremely high hardness (42-45 GPa) combined with very high toughness Extremely high heat resistance (up to 1200 C) Source: PLATIT

19 Characteristics of the coatings Hardness (GPa) TiN TiCN TiAlN AlTiN CrAlSiN TiAlSiN Hardness values over 40 GPa

20 Cr 1-x Al x N (no Si) Cr 1-x Al x N/SiN y low Si Cr 1-x Al x N/SiN y medium Si 40 Hardness [GPa] P870, x=0.41 P765, x= P966, x=0.49 P859, x=0.45 P768, x=0.49 P862, x=0.48 P965, x=0.61 P893, x=? P863, x=0.51 P867, x=0.57 P760, x=0.54 P967, x=0.64 P868, x=0.54 P757, x= Annealing Temperature [ C] Annealing Temperature [ C] Annealing Temperature [ C] Annealing performed for 2 hours in forming gas (N 2 / 8% H 2 ) Hardness measured at room temperature CrAlN without silicon loses up to 10 GPa after 1000 C annealing Cr 1-x Al x N/SiN y presents good stability at high temperatures important in cutting operations of heat resistant alloys

21 ? Origin of the High Thermal Stability C? Crystallite Size (nm) nc-tin/a-si 3 N 4 Kinetic stabilization by a slow diffusion excluded Surf. Coat. Technol 1998; 1999; Annealing Temperature ( C)/ 30 min nc-(tial)n/a-si 3 N 4 Absence of (TiAl)N decomposition 1200 C S. C. T. 2001; Mater. Sci. Eng. A 366 (2004) 202 Plastic Hardness (GPa) plastic hardness (GPa) (Ti 1-x Al x )N annealing temperature ( C) crystallite size (nm)

22 High Oxidation resistance Weight gain ( g / m 2 ) D. Münz 1986 D. Münz et al Veprek & Reiprich 1996 nc-tin/a-si 3 N 4 Cemented Carbide TiN TiAlN TiAlCrYN nc-tin/a-si 3 N 4 TiAlCrYN +topcoat The oxidation resistance of nc-tin/a-si 3 N 4 compares with that of advanced coatings S. Veprek, S. Reiprich, Li Shizhi, Appl. Phys. Lett. 66(1995)2540; S. Veprek and S. Reiprich, Thin Solid Films 268(1995)64 Surfr. Coat. Technol (1996) 394

23 Reduction of Oxygen impurities Plastic Hardness [GPa] Coating hardness can be increased over 80 GPa! XXXX Standard nc-tin/a-si 3 N 4 P CVD: Cl < 0.5 at.%, nc-tin/a-si 3 N 4 P CVD: Cl = 0.5 to 0.8 at.%, nc-tin/a-si 3 N 4 P CVD: Cl = 1 to 3.5 At.%, nc-tin/a-si 3 N 4 P CVD, Cl < 0.5 at.%, nc-tin/a-si 3 N 4 /a- & nc-tisi But 2 P CVD, Cl > 0.5 at.%, nc-tin/a-si 3 N 4 /a- & nc-tisi 2 P CVD (LiShizi), Cl > 0.7 at.%, nc-tin/a-si 3 N 4 /a-tisi 2 React. Sputt. of Ti & Si in N 2 - centr. cathode, nc-tin/a-si 3 N 4 React. Sputt. of Ti in N 2, Ar, SiH 4 +H 2 - planar magnetron, nc-tin/a-si 3 N Process 4 React. Sputt. of Ti & cost Si in N 2 - planar has magnetron, to be nc-tin/a-si evaluated 3 N 4 React. Sputt. of Ti & Si in N 2 - planar magnetron, nc-tin/a-si 3 N 4, ann 800 o C + Magnetron Sputtering by P. V. Needs implementation from lab to industrial equipment Coated tool performance (lifetime, cutting speed) has to be checked [H]=0.9 at.% [H]=10 at.% Oxygen Content [at%]

24 Results Wear on IN100 finishing tool -FRAISA solid carbide end mill -Diameter: 10 mm -Tip radius: 1 mm -3 flutes -Cutting speed: 40 m/min -Feed per tooth: mm -a p : 6 mm -a e : 0.5 mm

25 Wear on the cutting edge after L=1110 mm finishing Uncoated TiAlCN AlTiSiN Coatings reduce chipping and result in a more controlled and stable flank wear AlCrN AlTiN AlCrSiN

Plunge Milling in Inconel 718 Tool description Tool insert: MM12-12008-R20-PL-MD05 Diameter: 12 mm Radius:

of cutting edges: 2 Cutting data Cutting speed: Feed per tooth: Depth of cut (a p ): With of cut (a e ):

26 Plunge Milling in Inconel 718 Tool description Tool insert: MM R20-PL-MD05 Diameter: 12 mm Radius: 2,0 No. of cutting edges: 2 Cutting data Cutting speed: Feed per tooth: Depth of cut (a p ): With of cut (a e ): Cutting method: Machining length: Machining length: 21 m/min (first parameter set) 30 m/min (second parameter set) 0,05 mm (0,1 mm/rev) 20 mm 3 mm Plunging Measurement no. 1 = 220 mm Measurement no. 2 = 440 mm

27 Results: Second parameter set VB measured on end 0,150 0,125 Reference coating AlTiSiN 0,100 Vb 0,075 0,050 0,025 AlCrSiN AlCrSiN AlTiSiN + TiAlCO AlCrSiN AlTiSiN AlCrSiN AlCrSiN + CBC AlTiSiN 0,000 new tool used one time used twice Seco standard End Platitt Batch 838 End Platitt Batch 839 End Platitt Batch 884 End Platitt Batch 894 End Platitt Batch 938 End Platitt Batch 939 (tool 1) End SHM End SHM End SHM End

Commercial Ti(C,N)+(Ti,Al)N+TiN CrAlSiN (#838)

temperature properties of the nanocomposite

28 Commercial Ti(C,N)+(Ti,Al)N+TiN CrAlSiN (#838) CrAlSiN + CBC (#884) TiAlSiN (#894) Used two times Used one time In this demanding application, the coatings act like a thermal barrier and the high temperature properties of the nanocomposite coatings maintain the flank and end wear at an acceptable level

29 Benefits Increase machining efficiency: -Tool cost -Coating cost -Tool refurbishment -Machine cost -Tool life (from chipping catastrophic to continuous wear controllable) -Machining conditions

30 Tool life From catastrophic (chipping) to controllable (continuous wear): In production conditions, always in the safe side: Dispersion Tool life Usable tool life Average tool life With a continuous wear mechanism, tool life is much more predictable (less dispersion) -> less risk of unexpected failure (which can cause severe damage in very expensive components) -> Usable tool life is actually increased

31 But how does all this affect production costs? Let s see past experiences (project TITALUM 5FP)

32 UNIMERCO Reference Tool Cost ( ) Refurbishment Cost ( ) 62 No. of refurbishments 3 Lifetime of refurbished tool 100% Machine cost ( /hour) 60 No. of demonstrators/year Roughing with solid carbide tools. Same cutting conditions for all tools. -> The benefit comes mainly from tool saving Tool Machine Reference Coating A Coating B Coating C Coating D Coating E Untreated Ref. Project TITALUM (V FP) Machining costs of manufacturing 400 demonstrators. No tool refurbishment

33 What happens if machining conditions are optimised? 7.000, ,00 Material removed Tool lif etime Slotting , , , , , ,00 Unt r b Coat ing 1 a Coat ing 1 b Coat ing 2 Coat ing 3 Coat ing 4 0 Material removed during the lifetime of coated and uncoated UNIMERCO roughing end mills Ref. Project TITALUM (V FP)

34 Tool Machine Process cost ( ) Untr b Coating 1 a Coating 1 b Coating 2 Coating 3 Coating 4 Machining costs of roughing Ti6Al4V, corresponding to the production of one component in one year (several hundreds of units) Ref. Project TITALUM (V FP)

35 The benefits are (will be) related to the increase in productivity, i.e. reduction of machining time with an additional contribution in tool consumption saving. This will be achieved by the new developments allowing for more advanced machining conditions (tougher and quicker) and controlled tool wear development.

36 Thank you for your attention! And many thanks to all the participants in the project MACHERENA

Wear of PVD Coated and CVD+PVD Coated Inserts in Turning

Wear of PVD Coated and CVD+PVD Coated Inserts in Turning Paper No.: 65 Session No.: Author Name: Title: Affiliation: Address: Email: 56 (Dynamics and Vibrations in Experimental Mechanics) M.A. Zeb Assistant