Bonding Studies between Fracture Toughened Adhesives and Galvannealed Steels with Zinc Coating Dow Automotive Systems

Format:

Conference/Event

Author/Creator:

Bandekar, Bandekar, author.

Contributor:

Fenton, Jeffrey L.

Golden, Michael R.

Meyers, Greg

Yan, Benda

Conference Name:

SAE 2010 World Congress & Exhibition (2010-04-13 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2010

Summary:

Adhesive bonding technology is rapidly gaining acceptance as analternative to spot welding. This technology is helping automobilemanufacturers reduce vehicle weight by letting them use lighter butstronger advanced high strength steels (AHSS's). This can makecars safer and more fuel efficient at the same time. The otherbenefits of this technology include its flexibility, ability tojoin dissimilar materials, distribute stress uniformly, providesealing characteristics and sound dampening, and provide a moisturebarrier, thus minimizing the chance for corrosion. The lap shearwork reported in the late 1980s and early 1990s has led to theprevalent perception that the galvannealed (GA) coating candelaminate from the steels, resulting in poor joint performance.However, the above work was carried out on steels used primarily inautomobile outer body panels. The Dow Chemical Company andArcelorMittal collaborated on a joint project to carry outcomparative studies of bonding efficacies of fracture toughenedadhesives (FTA's) with conventional versus AHSS's. Three GAsteels, namely, extra deep drawing quality interstitial-free steel(EDDS-IF) and two high strength steels, namely, DP780 and TRIP 780were tested with two different adhesives, one FTA with a modulus of~ 1500 MPa and another conventional adhesive with a modulus of ~3500 MPaThe results of this joint study showed that the FTA, BETAMATE1496, exhibits significantly better energy absorption/impact loadthan the conventional hem flange adhesive, BETAMATE 73305.Whereas EDDS-IF steel led to coating delamination, the AHSS'sstudied showed cohesive failure without any coating delamination.This underscores the importance of an FTA during a crashperformance. Surface texture does not seem to be a factor inbonding in these systems. The AHSS's can take advantage of theadhesive bonding in automotive body structures to improvestructural integrity and crash performance. Results of lap shear,impact peel, microscopy, as well as suitable analytical testingwill be presented and discussed.This initial work primarily dealt with lap shear and impact peelwork carried out at ambient temperatures; it also included only alimited number of steels and adhesives. Future work plannedincludes GA steels covering a broader range of strengths as well asadhesives of broader modulus range. Also in plans is high speedimpact work covering a broader temperature range following theprocedure outlined in ISO 11343

Notes:

Vendor supplied data

Publisher Number:

2010-01-0434

Access Restriction:

Restricted for use by site license