1. Johnny K Larsson et al. Page 1 Issue date: 2008-10-28, Security Class: Open LättUHS Slutseminarium Swerea IVF, sal “Vinga”, Mölndal 2008-10-28 Weldability Testing of new Grades of Ultra High Strength Steels [Svetsbarhetsbedömning av nya UHSS-kvaliteter] Johnny K Larsson Joel Lundgren Martin Olsson Gert Larsson Glenn Hopkins Volvo Car Corporation, Gothenburg

2. Johnny K Larsson et al. Page 2 Issue date: 2008-10-28, Security Class: Open Table of Content LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28  Introduction of VCC’s Routines for Joinability  Scope of Welding Trials  Criteria for an Approved RSW 1-D Lobe  Aspects on RSW of UHSS  GMAW 2-D Lobe and Process Tolerances  Summary and Future Outlook

3. Johnny K Larsson et al. Page 3 Issue date: 2008-10-28, Security Class: Open Routines for Evaluation of “Joinability”  Resistance Spot Welding  Gas Metal Arc Welding  Laser Beam Welding  Brazing Technologies  Adhesive Bonding  Mechanical Joining  Fasteners (weld bolts & nuts) LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28

4. Johnny K Larsson et al. Page 4 Issue date: 2008-10-28, Security Class: Open Five Material Combinations for RSW : 21-5221.4 mm USIBOR 1500 P / 0.9 mm Rephos260 70G70G HD / 1.5 mm DP1000 70G70G HD 21-5231.5 mm DP1000 70G70G HD / 1.4 mm USIBOR 1500 P / 2.5 mm Rephos260 70G70G HD 21-5241.4 mm USIBOR 1500 P / 1.5 mm DP1000 70G70G HD / 2.0 mm Boron 1500 P 21-525Same as above but with adhesive Betamate XW-1496V between USIBOR and DP1000 21-5261.5 mm DP1000 70G70G HD / 1.5 mm DP1000 70G70G HD Two Material Combinations for GMAW: 135-911.5 mm DP1000 70G70G HD / 2.0 mm Boron 1500 P 135-921.5 mm DP1000 70G70G HD / 1.5 mm DP1000 70G70G HD LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Scope of Welding Trials RSW and GMAW of Material Stack-ups including DP1000 Reference Object: Volvo XC90

5. Johnny K Larsson et al. Page 5 Issue date: 2008-10-28, Security Class: Open Robust 1-D Welding Lobe for a Three Sheet Metal Stack-Up DP600 (1.65mm), Boron steel (1.4mm), mild steel (0.77mm) Current range > 1.0kAGood weldability 05 - 1.0kALimited weldability < 0.5kAUnacceptable weldability Minimum nugget diameter: 4.5 mm N.B. For classification in accordance to the above criteria, a nugget diameter d = d min + 1 mm shall be obtained before the spatter limit is reached 8.2-9.6 kA 6.4-4.5 mm LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28

6. Johnny K Larsson et al. Page 6 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #1 [JPS-nr. 21-522] Sill Inner / Rfr. Sill Inner / Sill Outer MaterialsThickness WSS-M1A322-A3 / AlSiBoron 15001.60 WSS-M1A341-A2 / 70G70G-HDRP 2600.90 WSS-M1A348-A9 / 70G70G-HDDP 10001.50 OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Electrode Force = 4.9 kN; Welding Time = 530 ms; Cooling Time = 150 ms

7. Johnny K Larsson et al. Page 7 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #2 [JPS-nr. 21-523] Sill Outer / Sill Inner / Cover Plate [without adhesive between sills] MaterialsThickness WSS-M1A348-A9 / 70G70G-HDDP 10001.50 WSS-M1A322-A3 / AlSiBoron 15001.60 WSS-M1A341-A2 / 70G70G-HDRP 2602.50 OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Electrode Force = 5.1 kN; Welding Time = 720 ms; Cooling Time = 150 ms

8. Johnny K Larsson et al. Page 8 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #3 [JPS-nr. 21-524] B-pillar Rfr. / Sill Outer / Sill Inner [without adhesive between sills] MaterialsThickness WSS-M1322-A3 / un-coatedBoron 15002.00 WSS-M1A348-A9 / 70G70G-HDDP 10001.50 WSS-M1A322-A3 / AlSiBoron 15001.60 OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Electrode Force = 5.2 kN; Welding Time = 680 ms; Cooling Time = 150 ms

9. Johnny K Larsson et al. Page 9 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #4 [JPS-nr. 21-525] B-pillar Rfr. / Sill Outer / Sill Inner [with Betamate XW-1496V adhesive between sills] MaterialsThickness WSS-M1322-A3 / un-coatedBoron 15002.00 WSS-M1A348-A9 / 70G70G-HDDP 10001.50 WSS-M1A322-A3 / AlSiBoron 15001.60 Weld lobe size identical to 21-524 !! 7.9 – 9.4 kA OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Electrode Force = 5.2 kN; Welding Time = 680 ms; Cooling Time = 150 ms

10. Johnny K Larsson et al. Page 10 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #5 [JPS-nr. 21-526] Basic Testing MaterialsThickness WSS-M1A348-A9 / 70G70G-HDDP 10001.50 OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Electrode Force = 4.9 kN; Welding Time = 400 ms; Cooling Time = 150 ms

11. Johnny K Larsson et al. Page 11 Issue date: 2008-10-28, Security Class: Open Aspects on Spot Welding of High, Extra High and Ultra High Strength Steels  Increased electrode force  Increased weld time  Decreased weld current  Optimized hold time to avoid brittleness  Pulsed welding is favourable  Larger electrode caps are recommended Risk of pore formation Occurrence of partial plug failure LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28

12. Johnny K Larsson et al. Page 12 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #6 [JPS-nr. 135-91] Sill Outer / B-pillar Rfr. OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Power Source:Fronius TPS4000 Wire Feeder: Robacta Drive VR 1500 Shielding Gas:Ar 80% / CO2 20% [ATAL] Filler Wire:EN-440 G3Si1  1.0 mm MaterialsThickness WSS-M1A348-A9 / 70G70G-HDDP 10001.50 WSS-M1322-A3 / un-coatedBoron 15002.00

13. Johnny K Larsson et al. Page 13 Issue date: 2008-10-28, Security Class: Open Welding Lobe for Materials Combination #7 [JPS-nr. 135-92] Basic Testing OK LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 MaterialsThickness WSS-M1A348-A9 / 70G70G-HDDP 10001.50 Power Source:Fronius TPS4000 Wire Feeder: Robacta Drive VR 1500 Shielding Gas:Ar 80% / CO2 20% [ATAL] Filler Wire:EN-440 G3Si1  1.0 mm

14. Johnny K Larsson et al. Page 14 Issue date: 2008-10-28, Security Class: Open Robot  Correct welding position  Perpendicular angel towards the sheets Product  Geometry and gaps  Spatter protection (covers) Welding gun  Good electrode matching  No electrode slipping  The electrical circuit and copper parts checked  Cooling water circuit OK Critical Parameters for an Optimal Spot Welding Result Welding parameters  Welding current  Welding time  Gun force  Pulse & slopes )  Polarity at MFDC (Peltier effect) Tipdresser  Good cutter-knifes LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28

15. Johnny K Larsson et al. Page 15 Issue date: 2008-10-28, Security Class: Open LättUHS Slutseminarium, Swerea IVF Mölndal, 2008-10-28 Johnny K Larsson, jlarsso1@volvocars.com Thank you for your attention!