Investigation on the influence of adhesive properties on the formability of adhesive-bonded steel sheets

Abstract

The main aim of this research work is to study the influence of adhesive properties on the formability of adhesive-bonded steel sheets. The adhesive properties were varied by having two different adhesives, epoxy based and acrylic based, and by changing the hardener to resin ratios. The deep drawing quality cold rolled steel and stainless steel (SS 316L) sheets were used as base materials. The epoxy and acrylic adhesives show improved elongation with increase in hardener to resin ratio. This is because of changeover of resin-rich formulation to hardener-rich formulation, making the sample more ductile. The adhesive-bonded blanks show improved elongation as compared to double sheets, which is due to the presence of adhesive delaying the onset of necking. With increase in hardener to resin ratio of both the adhesives, the elongation of individual sheets has improved. This is due to the improvement in elongation of adhesives with increase in hardener to resin ratio. The strain hardening exponent ( n) of adhesive-bonded blanks has improved with increase in hardener to resin ratio in all the regions of deformation. The limit strain of deep drawing quality and SS 316L sheets constituting adhesive-bonded blanks shows improvement with increase in hardener to resin ratio. The adhesive-bonded blanks with interface bonding exhibit better limit strain as compared to the case without interface bonding.