Evaluation of mechanical and laser surface pre-treatments on the strength of adhesive bonded steel joints for the automotive industry

Abstract

Recent research efforts in the automotive industry have been focused on the integration of high-strength steels within lightweight vehicles by using improved joining techniques. The present work falls in this subject area and is focused on the analysis of adhesive bonded dual-phase steel/epoxy joints for the automotive industry. Two quasi-static loadcases were considered, i.e. single-lap and T-peel tests, and various surface preparation strategies were evaluated. In particular, the mating surfaces were pre-treated by using pulsed laser irradiation with a fiber laser (1064 nm) and comparisons were made with degreasing and sand blasting. Moreover, the effects of bondline thickness and adhesive type were also assessed. To this aim, two epoxy adhesives with fairly different mechanical behavior (i.e. strain hardening versus elasto-plastic) were deployed for joints fabrication. Finally, T-peel tests were also carried out after sample cycling under controlled high humidity and temperature (i.e. accelerated aging). The obtained results highlighted the beneficial effect of laser irradiation on the joints’ mechanical behavior under both static and hydrothermal loadings

Influence of Adherend Surface Roughness on the Adhesive Bond Strength

“…In order to get a strong and durable bonded joint, a surface treatment of adherends should ensure the following aspects: removal of all contaminants (lubricants, dusts, loose corrosion layers, micro-organisms) from the surfaces (da silva et al, 2009), good surface wettability (Encinas et al, 2012;Sedev et al, 2014), surface energy (Guzanova et al, 2014;Islam et al, 2014), good activation of surfaces of elements being bonded (Encinas e al., 2014) etc. There are different chemical and physical surface treatments available, but proper selection of surface treatment is very important (Rotella et al, 2016;Williams et al, 2014;Maressa et al, 2015).…”

Impact study of single stage and multi stage abrasive machining on static strength of lap adhesive joints of mild steel

“…Before bonding all the samples' surfaces after mechanical working were degreased with a degreasing agent Loctite 7063. The processes of mechanical working and degreasing are described in the references [5,[15][16][17]. There were 16 samples in total -4 of each surface preparation variant served to the surface roughness examination.…”

Selected Strength Aspects of Adhesive Lap Joints and Butt Welded Joints of Various Structural Materials

“…Individual operations may consist of a number of stages of specific technological parameters; they might also require various items of equipment and instrumentation. Detailed conditions of adhesive bonding operation are selected based on, inter alia, the type of substrate, the geometry of elements and structures, joint assembly conditions, production type, etc [11].…”