ISO 4386-1:2012 specifies an ultrasonic testing method for determining bond defects between the bearing metal and the backing. The test can be performed on metallic multilayer plain bearings consisting of steel- or copper-based material backings lined with bearing metal based on lead and tin, with layer thicknesses greater than or equal to 0,5 mm. For cast iron backings, ISO 4386-1:2012 is applicable with restrictions.