Tool and Die Design for Deep Drawing AHSS Prof. Dr.-Ing. Dr. h.c. Klaus Siegert Dipl.-Ing. M. Vulcan

Transcription

1 Prof. Dr.-Ing. Dr. h.c. Klaus Siegert Tool and Die Design for Deep Drawing AHSS Prof. Dr.-Ing. Dr. h.c. Klaus Siegert Dipl.-Ing. M. Vulcan

2 High Strength Steel Sheets Stretch Drawing of Flat Parts Controllable Draw Beads Cushion Systems and Die Design Summary WagnerS (2)

3 Multiphase Steel Increase of strength by microstructural change Isotropic Steel Higher-Strength IF-Steel Concerted control of grain refining by adding Titanium Solid solution hardening Bake Hardening Steel Dual Phase Steel Phosphorus-Alloyed Steel Diffusion of interst. N und C to increase the yield strength Embedding hard martensite parts in ferritic matrix Solid solution hardening by adding phosphorus Micro-Alloyed Steel Hardening by carbides of micro alloy elements Ti, Nb, V Source: Thyssen Development of High Strength Steels WagnerS (3)

4 Elongation at Fracture A 80 (%) Bake Hardening - Steel HSLA 180BH HSLA 300BH Isotropic HSLA 220i HSLA 280i IF- Steel IF 180 IF 260 Phosphor alloyed HSLA 220P HSLA 300P TRIP - Steel TRIP 700 TRIP 800 Micro Alloyed 10 HSLA 260 HSLA Dual-Phase Steel DP 500 DP 600 Complex-Phase - Steel CP-W 800 CP-W Martensite- Steel MS-W 1000 MS-W 1200 Tensile Strength R m (MPa) Comparison of Different Steel Grades WagnerS (4)

5 900 k f [N/mm²] TRIP 700 DP 600 DP 500 IF 260 FePO ,05 0,10 0,15 ϕ g Source: IFU Logarithmic True Strain Flow Curves of Actual Sheet Metals WagnerS (5)

6 Yield Strength in MPa min max UTS in MPa min max Elong. at Fracture A 80 in % 0 R-Value High Strength Bake-Hardening Steels HSLA 180 BH r m = 1,9 HSLA 220 BH r m = 1,5 HSLA 260 BH r m = 1,4 HSLA 300 BH r m = 1,3 High and Advanced High Strength Steels DP ,9 DP DP TRIP ,8 CP MS ,7 Source: Birzer WagnerS (6)

7 High Strength Steel Sheets Stretch Drawing of Flat Parts Controllable Draw Beads Cushion Systems and Die Design Summary WagnerS (7)

8 Punch Hydraulic Valves Gripper Frame Blankholder Source: T. Krockenberger, IFU Test Equipment for Stretch Drawing followed by Deep Drawing WagnerS (8)

9 Source: T. Krockenberger, IFU Test Equipment for Stretch Drawing followed by Deep Drawing, Installed in Single Acting Hydraulic Press at IFU WagnerS (9)

10 Source: D. Vlahovic, IFU First Stage: Clamping the Sheet WagnerS (10)

11 Source: D. Vlahovic, IFU Second Stage: Predefined Stretching of the Sheet WagnerS (11)

12 Source: D. Vlahovic, IFU Third Stage: Tool Closing WagnerS (12)

13 Source: D. Vlahovic, IFU Last Stage: Deep Drawing of the Sun Roof Panel WagnerS (13)

14 Principal Strain after Deep Drawing Principal Strain after Pre-Stretching Source: D. Vlahovic, IFU Results FEM Process Simulation WagnerS (14)

15 High Strength Steel Sheets Stretch Drawing of Flat Parts Controllable Draw Beads Cushion Systems and Die Design Summary WagnerS (15)

16 Springback Reduction: Increased Wall Stresses in the Straight Sides by Driving the Active Drawbeads Upwards. Guideline: σ Wall < 0,8 σ Fracture σ Fracture Safety Factor Safety Distance σ z, Wall, Drawbead σ z, Wall, Basic Source: S. Beck, IFU Desired Wall Stress Distribution WagnerS (16)

17 Safety Distance Additional Force by Increased Blankholder Force and/or Increased Drawbead Height Intention: Improved Wall Quality by Introducing Additional Forces Source: S. Beck, IFU Desired Punch Force Trajectory WagnerS (17)

18 Load Cell Vertical Force Elastic Hinge Horizontal Force in the Sheet (Restraining Force) Side Wall Stress Sensor Force in the Sheet Punch Source: S. Beck, IFU Side Wall Stress Sensor WagnerS (18)

19 Drawbead 3 Connected Optional Drawbead 2 Sensor Drawbead 4 Drawbead 1 Source: S. Beck, IFU Position of the Wall Stress Sensors and Position of the Drawbeads WagnerS (19)

20 Stress at Fracture Stress in N/mm Stress 1 Stress 2 Stress 3 Stress Stroke in mm Quelle: S. Beck, IFU Side Wall Stress vs. Stroke for Constant Draw Bead Heights WagnerS (20)

21 R r= 1/R Source: S. Beck, IFU Curvature of the Side Wall for Variable Draw Bead Heights vs. Stroke WagnerS (21)

22 Source: M. Beth Springback Phenomena when Drawing U-Profiles WagnerS (22)

23 Sidewall of the Part, drawn without Drawbeads Sidewall of the Part, drawn with Controllable Drawbeads Source: S. Beck, IFU Surface Quality with and without Controllable Drawbeads (Measured with the System Diffracto) WagnerS (23)

24 High Strength Steel Sheets Stretch Drawing of Flat Parts Controllable Draw Beads Cushion Systems and Die Design Summary WagnerS (24)

25 Box-Profile C-Profile Source: M. Häussermann, IFU Design of Conventional Draw Dies WagnerS (25)

26 Blankholder Pressure: N/mm 2 Source: M. Häussermann, IFU Blankholder Pressure by the Box-Profile WagnerS (26)

27 Locally increased Blankholder Pressure Blank Draw Ring Blankholder F Pin F Pin F Pin F Pin, increased Source: M. Häussermann, IFU Principle of the Segment-Elastic Blankholder WagnerS (27)

28 Prismatc Designed Draw Ring Draw Die with Segment-Elastic Blankholder, Prismatic Designed Draw Ring and 10-Point Cushion System Integrated into the Die Segment-Eelastic Blankholder Punch Guide Return Stroke Cylinders Stroke Measurement Servo Valves Hydraulic Cylinders Bottom Plate Source: M. Häussermann, IFU WagnerS (28)

29 Source: M. Häussermann, IFU Hydraulic Multipoint Cushion System in the Die WagnerS (29)

30 Normal Pressure: 4, N/mm 2 Equal Pin Forces Increase of 100% in the Middle Area Source: M. Häussermann, IFU WagnerS (30)

31 Total Blankholder Force 530kN Good Part with 68 mm Draw Depth 7 kn 102 kn 99 kn 13 kn 43 kn 24 kn 2 kn 90 kn 98 kn 52 kn Source: M. Häussermann, IFU Optimization of the Cushion Pin Forces WagnerS (31)

32 Die for the Deep Drawing of Longitudinal Beams with Cushion System integrated into the Die Punch Blankholder Valves 18 Nytrogen Cylinders Source: D. Haller, IFU Cables and sensors WagnerS (32)

33 Die for the Deep Drawing of Longitudinal Beams with Cushion System integrated into the Die Source: D. Haller, IFU WagnerS (33)

34 Experimental Die Source: J. Hengelhaupt, IFU WagnerS (34)

35 Hydraulic HMI Main Mobile Hydraulic Unit Press HMI 10 Point Flexible Binder Die kn Hydraulic Press at the IFU IFU HMI MOOG Controller Units Source: IFU HYDAC Power Unit Cooling System 2 x Return Tank Units 2 x Bladder Accumulators Station (each 1 x 60 bar and 2 x 10 bar) WagnerS (35)

36 Source: M. Vulcan, IFU Control system with Touch Screen to Adjust the Blankholder Pressure Area by Area WagnerS (36)

37 Nominal Value Friction Force versus the Stroke Max. Wrinkle Height Controller Actual Values Stroke Ram Measuring Friction Force and Wrinkle Height Upper Binder Segment-elastic Blankholder Cushion System integrated into the Die Source: IFU Design of Closed Loop Control of the BHF WagnerS (37)

38 Tool and Die Design for Deep Drawing AHSS WagnerS (38)

39 Stuttgart w University w w. a u t o s t e e l. o r g AK Steel Corporation Dofasco Inc. Great Designs in Steel is Sponsored by: Mittal Steel Company Nucor Corporation Severstal North America Inc. United States Steel Corporation WagnerS (39)