hiIn 1938, Lludwig Bergman and some colleagues were experimenting with ultrasonic Waves and their effects on metal. He found that many metals could be combined by using ultrasonic welding that could not be joined by any other method. It was also found that any metal could be strengthened by subjecting the metal in its molten state to ultrasonic vibrations.

The ultrasonic effect upon the molten metal generates a smaller grain size, giving the metal more strength. Ultrasonic welding combines pressure and high frequency vibration motions to form a solid state bond.