Role of Contact Angle in the Performance Improvement of Adhesively Bonded Metal Joints at Cryogenic Temperatures

Abstract

The performance of adhesively bonded joints composed of aluminum sheet and stainless steel foils was investigated at the cryogenic temperature for the secondary barrier LNG (Liquefied Natural Gas) containment system. Since the huge adhesive bonding area such as LNG carriers or floaters cannot be surface-treated economically by chemical treatment, in this work, a new flame surface treatment method for the stainless steel foil, is evaluated and compared with other conventional surface treatments such as mechanical or chemical surface treatments at the cryogenic temperature. The effects of adhesive thickness on the adhesive bond strength and fracture toughness have been also investigated at the cryogenic temperature, and the effect of repeated thermal shocks on the adhesive joint was evaluated. The experimental results showed that the bonding performances depended strongly on the surface treatment method, adhesive thickness and reinforcement for the adhesive. It was also found that the thick adhesive joint had a reduced bonding strength at the cryogenic temperature, but the randomly oriented glass fiber reinforcement improved much the bonding strength and fracture toughness for thicker adhesive at the cryogenic temperature.