Mechanical Attachment of Fasteners to UHSS Materials

Transcription

1 Mechanical Attachment of Fasteners to UHSS Materials Rob Edwards PROFIL System Incorporated

2 Agenda Mechanical Attachment of Fasteners to UHSS Materials 1. Mechanical Fastener Basics 2. Evolution: Market Demands 3. Response to Evolution 4. UHSS Challenges 5. Initial Response to UHSS 6. Second Generation UHSS 7. Conclusion

3 Mechanical Fastener Basics Panel Preparation Self-Pierce Pre-Pierce and Form Joining Configuration Clinch Rivet Panel is packed into the fastener Fastener is formed around the panel

4 Evolution: Market Demands 70 Years of Evolution And Beyond Mild Steels High Strength Steels AHSS UHSS IF Mild IF IS BH CMn TRIP HSLA DP MART Innovation Drivers Material advancements CAFE standards Structural demands Assembly efficiencies

5 Response to Evolution Mild Steels High Strength Steels AHSS UHSS IF Mild IF IS BH CMn TRIP HSLA DP MART Rectangular Pierce Nuts

6 Response to Evolution Mild Steels High Strength Steels AHSS UHSS IF Mild IF IS BH CMn TRIP HSLA DP MART Rectangular Pierce Nuts Round Clinch Fasteners

7 Response to Evolution Mild Steels High Strength Steels AHSS UHSS IF Mild IF IS BH CMn TRIP HSLA DP MART Rectangular Pierce Nuts Round Clinch Fasteners Round Rivet Fasteners

8 Response to Evolution Mild Steels High Strength Steels AHSS UHSS IF Mild IF IS BH CMn TRIP HSLA DP MART Rectangular Pierce Nuts Round Clinch Fasteners Round Rivet Fasteners

9 UHSS Challenges Fastener Challenges in UHSS MPa Hot form / post quench Dimensional variability due to thermal deformation Post quench holes require special processing Laser cutting Non-traditional piercing

10 Initial Response to UHSS Panel Preparations No Emboss Laser Hole Emboss Laser Hole No Emboss No Hole

11 Initial Response to UHSS Thermal Deformation Panel Preparation Case 1 Case 2 Pre-press hardening Press hardening Laser cutting Emboss Installed fastener position Actual Intended Actual

12 Initial Response to UHSS No Emboss Laser Hole Laser cut hole after press hardening punch nut die button

13 Initial Response to UHSS Emboss Laser Hole Emboss formed during press hardening Laser cut hole after hardening punch nut die button

14 Initial Response to UHSS Emboss Laser Hole Emboss formed during press hardening Laser cut hole after hardening punch stud die button

15 Initial Response to UHSS Series Production Application Emboss formed during press hardening Laser cut hole after hardening

16 Initial Response to UHSS Rivet Performance Mild Steel (210 MPa) HSS (600 MPa) UHSS (1500 MPa) OEM A OEM B Destruct Test Test Torque (Nm) Push-Out (kn) na 4.9 Property Class mm sheet thickness RND Nut - M6

17 Second Generation UHSS Goal: Improve Manufacturing Efficiency Eliminate laser hole cutting Time savings Solves positional accuracy issues hole and emboss Eliminate emboss positional deviation from thermal deformation

18 Second Generation UHSS Development Criteria 1. Self-piercing 2. Post-quenching installation 1500 MPa minimum 3. Minimal stress concentration resulting from piercing 4. > 30 Nm torque performance 5. >2.0 kn push-out performance

19 Second Generation UHSS Development Criteria 1. Self-piercing 2. Post-quenching installation 1500 MPa minimum 3. Minimal stress concentration resulting from piercing 4. > 30 Nm torque performance 5. >2.0 kn push-out performance

20 Second Generation UHSS Development Criteria 1. Self-piercing 2. Post-quenching installation 1500 MPa minimum 3. Minimal stress concentration resulting from piercing 4. > 30 Nm torque performance 5. >2.0 kn push-out performance

21 Second Generation UHSS Development Criteria 1. Self-piercing 2. Post-quenching installation 1500 MPa minimum 3. Minimal stress concentration resulting from piercing 4. > 30 Nm torque performance 5. >2.0 kn push-out performance

22 Second Generation UHSS Development Criteria Self-piercing 2. Post-quenching installation 1500 MPa minimum 3. Minimal stress concentration resulting from piercing 4. > 30 Nm torque performance 5. >2.0 kn push-out performance Cutting edge at 2 0 draft, creating an under cut to set the panel material into, achieving push-out performance

23 Second Generation UHSS Benchmarking Development nut vs weld nut - dynamic load durability Laser cut hole preparation vs self-pierced hole Microstructure grain orientation bias

24 Second Generation UHSS Benchmarking Development nut vs weld nut - dynamic load durability Development Nut Weld Nut

25 Peek Force F [N] Second Generation UHSS Benchmarking Laser cut hole preparation vs self-pierced hole Self-Pierced Laser Cut Nut: Pierce Nut RSE08, Self-Piercing / Pre-Pierced by Laser Sheet metal: USIBOR, 1.7 mm Counterpart: DC04, 5 mm Screw: M8 PC 8.8 with flange Fastening Torque: 24 Nm Load Transmission: Chuck Forth Ratio Fu/Fo: R = Number of Cycles n

26 Second Generation UHSS Benchmarking No microstructure grain orientation bias 45 0 Orientation 0 0 Orientation

27 Second Generation UHSS Installation tooling and feeding equipment to support production Photo 1 Photo 2

28 Second Generation UHSS 1.8 mm PHS 1500 MPa

29 Conclusion Self-piercing is an ideal process for press-hardened steel Push out and torque values are production worthy Dynamic properties are superior to weld fasteners No cracking has been observed during micro inspection Feeding equipment and installation tooling are production ready Die button has demonstrated acceptable performance at over 10,000 hits This is the Next Generation of UHSS fasteners

30 Thank you for your attention Questions and Discussion

31 North American Light Vehicle Metallic Material Trends PRESENTATIONS WILL BE AVAILABLE MAY 16 Use your web-enabled device to download the presentations from today s event Great Designs in Steel is Sponsored by: