ECOSHAPE. Economic Advanced Shaping Processes for Integral Structures. Tobias Hornfeck Achim Schoberth

Transkript

1 ECOSHAPE Economic Advanced Shaping Processes for Integral Structures Tobias Hornfeck Achim Schoberth

2 Structure 1. State of the art 2. ECOSHAPE consortium 3. Project aims 4. Laser beam forming of aluminium alloys 5. Mechanical properties of formed structures 6. Corrosional behavior 7. Further work content Seite 2

3 1. State of the art Sheet Metal (planar) Machining (planar) Mechanical forming Joining (3-D-formed) Reshaping Challenges: Cost intensive forming tools (specific for each structure) High effort for 3-D-Processing Seite 3

4 2. Consortium founded by the EC Industrial End-Users University research instutues Industrial R&D Seite 4

5 3. Project aims Sheet Metal (planar) Mechanical Processing (planar) Joining (Laser) Laser Beam Forming (LBF) Project Aims: Reduction of process steps Processing in flat condition Reduction of tooling costs Requirements: Max. 10 % decrease of material Properties acceptable Processing of several alumnium alloys: 1424, 2022, 2024, 6013, Seite 5

6 4. LBF - Basic mechanism Heat absorption by Laser Thermal extension of irradiated surface: Elastic contrary forming Further energy induction by Laser: Plastification of irradiated side Thermal extension of opposite side Forming to desired direction Temperature Gradient Mechanism Solidification of plastificated area Seite 6

7 4. Structure of control system Geometrical data for formed structure by design actual shape of structure Structure i Control system Structure ready for assembly location and power for LBF Seite 7

8 5. Maximum forming capability Biegewinkel T4 Bend Angle [deg] 1 0,8 0,6 0,4 0,2 Power 0 0,00 5,00 10,00 15,00 20,00 Feed Rate [mm/s] BUT: Surface brightness influences absolute Laser Power and Feed Rate values! mittlerer Biegewinkel [ ] Bend Angle [deg] Result: Forming capability increases with increasing Laser Power Risk of lokal melting increases with increasing power Power W, 12.5 mm/s, mech. gefräste Oberfläche Leistung [W] Thickness [mm] Seite 8

9 5. Hardness and strength HV0, Depth 0,5 mm Depth 1,0 mm Depth 1,5 mm Abstand Distance in [mm] Laserpath Result: Negligible influence of laser forming on static mechanical properties BUT: AA 1424TX shows heavy loss of hardness and strength after LBF Alloy in aged condition not suitable for LBF! Tension Zugkraft [MPa] Several Reference forming 150 variations Dehnung [%] Elongation [%] Seite 9

10 5. Crack propagation 0,1 AA6013 T6 AA6013 T6 LBF AIMS ,01 da/dn (mm/cyc) crackform right side: V left side: 45 0,001 Material: Specimen ID: Width: Thickness: Stress Ratio: Frequency, Hz: AA6013 T6 RiFo4 3,2 400,1 3,25 0,1 6 mm mm 0, delta k (MPam^0,5) Seite 10

11 5. Fatigue laser beam formed laser beam formed; run outs laser beam formed; Whöler curve reference reference; run outs reference; Whöler curve 250 Tension [MPa] ,00E+00 1,00E+01 1,00E+02 1,00E+03 1,00E+04 1,00E+05 1,00E+06 1,00E+07 1,00E+08 Cycles Seite 11

12 6. Corrosional behavior Intergranular corrosion (ASTM G110): Very slight increase of corrosion depth within LBF after 6 h, but uncritical in all cases Grain boundary Exfoliation corrosion (ASTM G34): No visible attack after 72 h Scattered corrosion visible after 72 h; improvement of corrosion behavior by LBF Salt spray test (ASTM B117): No corrosion effects on surface visible Seite 12

13 6. Corrosional behavior Intergranular corrosion (ASTM G110): Very slight increase of corrosion depth within LBF after 6 h, but uncritical in all cases Laser path Exfoliation corrosion (ASTM G34): No visible attack after 72 h Scattered corrosion visible after 72 h; improvement of corrosion behavior by LBF Salt spray test (ASTM B117): No corrosion effects on surface visible Seite 13

14 6. Corrosional behavior Intergranular corrosion (ASTM G110): Very slight increase of corrosion depth within LBF after 6 h, but uncritical in all cases Exfoliation corrosion (ASTM G34): No visible attack after 72 h Scattered corrosion visible after 72 h; improvement of corrosion behavior by LBF Salt spray test (ASTM B117): No corrosion effects on surface visible Seite 14

15 7. Further work contents Summary: Laserpower and feed rate found to be the major inluencing parameters for the process control Negligible influence of laser forming on mechanical properties except 1424TX Corrosional behavior comparable to basic material BUT: Surface brightness influences forming parameters strongly! LBF & Further work contents: Automation of process control Integration of quality assurance Influence of stiffening elements Seite 15

16 Contact Dipl.-Ing. Tobias Hornfeck Room 1306 Tel +49 (0) 89 / Fax +49 (0) 89 / tobias.hornfeck@iwb.tum.de Adress iwb - TU München Boltzmannstraße Garching Coordinator: Dipl.-Ing. Achim Schoberth Tel +49 (0) 89 / Achim.Schoberth@eads.net