The ultrasonic method that steers a sound beam by the use of multiple elements is known as:

usual multiple elements used Phased array method.

Ultrasonic control of rolling stock and subway components – AFER 1999

Phased Array ultrasonic testing

visuel examination,

magnetic particle

liquid penetrant tests 

radio-graphic inspection.

Phased Array Ultrasoic Testing with Multiple elements 

The method is Phased Array Technique

this method is called phased array