Method and device for the ultrasonic material testing of workpieces

摘要

The invention relates to a method for the acoustic coupling of a specimen in ultrasonic material testing of workpieces with an ultrasonic test head, in which the transmission of the emitted sound onto the specimen is achieved by means of a magnetic liquid arranged between the specimen and the test head, the said liquid being held by a magnetic field acting on it and having the emitted sound running through it. In order to provide a method which, under exactly defined coupling conditions and in a long-lasting testing cycle, allows a safe and reliable as well as reproducible test in the case of ferromagnetic and non-ferromagnetic and electrically non-conducting specimens, and to provide a device which is simple to produce and easy to manage, it is proposed that a strongly inhomogeneously pronounced magnetic field is generated, whose field gradient reaches its largest value in the region of the introduced quantity of the magnetic liquid between the test head and the specimen surface, the bundle of sound waves is led through the magnetic liquid inside the propagation surface which is adjusted by means of the magnetic field and the magnetic liquid which is gradually consumed during a long-lasting test cycle is continuously replaced. <IMAGE>