Connect, no.86, May 1997, p.3
Permabond has been working for a client to develop a material to be used in stainless steel fabrications. TWI was asked to examine the use of ultrasonics to produce a quantifiable assessment of bond quality at the steel/adhesive interface for all steel material combinations tested.
Two types of adhesive and two surface preparations - as-received and degreased and shot-blasted - were examined. Preliminary ultrasonic tests gave good results and confirmed the superior performance of one of the adhesive systems. The necessity to pre-treat the metal surfaces to ensure long-term durability of the adhesively bonded interface was also established.
Following this, it was decided to take one steel/adhesive combination for both surface preparations and subject them to environmental testing to establish the tolerance of the bond to more extreme variations in temperature. Again ultrasonic results showed the importance of surface preparation, with the shot-blasted specimen showing little or no apparent deterioration in bond quality and the specimen in the as-received condition showing severe disbonding over the whole inspected surface.
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