Forskningstrender inom mekanisk fogning vid Centre for Joining and Structures Svets- och fogningsteknik, Elmia

Transkript

1 Forskningstrender inom mekanisk fogning vid Centre for Joining and Structures Svets- och fogningsteknik, Elmia Karl Fahlström Research leader, Joining Technology Ph.D. student at University West

2 Forskningsfokus för mekanisk fogning Svårsvetsade material Höghållfasta material R&D Fixturering vid limning Mixfogar CFRP

3 Svårigheter med olika materialkombinationer B-stål Fe Svårt att få B-stålet att deformeras Dålig låsning Svårt att penetrera fogen Sprött beteende Fe - Al Olika egenskaper efter fogning Korrosion CFRP - Fe Deformerad/delaminerad fiberstruktur Sprött beteende Korrosion

4 Borstål Lösning 1: Utan softzone Med softzone Lösning 2: Högre hållfasthet på nitar!

5 RIVTAC Source: LWF, Paderborn

6 Source: LWF, Paderborn

7 Specimen type Crosssection view Joining test Materials 1: CFRP with epoxy matrix, t=2,6 mm 2: 22MnB5+AS150 t=1,5 mm Joining Method High-speed punch nailing w/o bonding Process parameter Join pressure: 4,5 bars Blank holder: 1,5 bars Joining possible 1: homogeneous rim hole 2: reduction of joining pressure (-0,25 bars) Source: LWF, Paderborn

8 Specimen type Close-up of lower rim hole Joining test Materials 1: CFRP with epoxy matrix, t=2,6 mm 2: 22MnB5+AS150, t=1,5 mm Joining Method High-speed punch nailing w/o bonding Process parameter Join pressure: 4,5 bars Blank holder: 1,5 bars Top layer of coating (Al 2 O 3 ) damaged around rim area by deformation of sheet Homogeneous rim hole area Source: LWF, Paderborn

9 Resistance Element Welding Source: LWF, Paderborn

10 EjoWELD Joining aluminium to press-hardened steels Joining direction from aluminium to steel No pre-hole operation needed High mechanical strength Possible to combine with adhesive Two-sided access required Need of an extra element Head side elevation 3 mm Head side needs to be seeled off in wet zones Source: Johnny K Larsson, EJOT

11 Friction element welding (FEW) Source: LWF, Paderborn

12 Specimen type Joining test Crosssection view, treated with acid Materials 1: CFRP with PA matrix, t=3,1 mm 2: DP800+Z100, t=1,5 mm Joining possible Almost perfect torus Sufficient friction welding zone No fiber rovings are transfered or deflected in head cavity 1 mm Joining Method Friction element welding Process parameter rotation: rpm max. force: 7,16 kn

13 Specimen type Joining test Crosssection view, treated with acid Materials 1: CFRP with PA matrix, t=3,1 mm 2: 22MnB5, t=1,5 mm Joining Method Friction element welding w/o bonding Process parameter rotation: rpm max. force: 7,7 kn result with increased force, better-looking torus, but head of element enters CFRP Source: LWF, Paderborn

14 Specimen type Joining test Crosssection view, treated with acid Materials 1: CFRP with PA matrix, t=3,1 mm 2: 22MnB5+AS150, t=1,5 mm Joining Method Friction element welding w/o bonding 1 mm Process parameter rotation: rpm max. force: 14,0 kn Joining not possible, even with maximum force of machine AlSi top coating with it s high hardness avoids propper surface activation of 22MnB5 sheet Source: LWF, Paderborn

15 Self-piercing-turn-solid-riveting In-forming of the rivet head by softening the polymer matrix and displacement of the CFRP material Source: Johnny K Larsson

16 Flow Drill Screwing Source: EJOT

17 Utmattningsdata - olika metoder och materialkombinationer

18 Latest All-Aluminium Body Structure Range Rover [L405; SOP 2012] SPR is the main joining technology (3,873 rivets) In combination with 1K adhesive* bonding (161 m) Blind rivets for single sided joint access No welding in the bodyshop 18 types of rivets 28 types of dies 95 rivet/die combinations 246 different material stack-ups 1 to 9 stacks per rivet gun 212 (51 designs) C-frame rivet guns 48 pedestal rivet machines Passive or active rapid (4 sec) filling of magazines by blow feeding 170 2T-stack-ups 2,762 rivets 76 3T-stack-ups 1,111 rivets *) SikaPower Source: Johnny K Larsson

19 Vi arbetar på vetenskaplig grund för att skapa industrinytta.