What is ISO 22232-2 about?  
ISO 22232-2 is the second part of the ISO 2223-2 series of standards that specifies the characteristics of probes. The probe is used for non-destructive ultrasonic testing in the following categories with center frequencies in the range of 0,5 MHz to 15 MHz, focusing or without focusing means:
- Single-or dual-transducer contact probes generating longitudinal and/or transverse waves
- Single-transducer immersion probes
Where material-dependent ultrasonic values are specified in ISO 22232-2 they are based on steels having a sound velocity of (5 920 ± 50) m/s for longitudinal waves, and (3 255 ± 30) m/s for transverse waves.
Note1: ISO 22232-2 excludes periodic tests for probes. Routine tests for the verification of probes using on-site procedures are given in ISO 22232-3.
Note2: ISO 22232-2 also excludes ultrasonic phased array probes, therefore see ISO 185632.
Note3: If parameters in addition to those specified in ISO 22232-3 are to be verified during the probe’s lifetime, as agreed upon by the contracting parties, the procedures of verification for these additional parameters can be selected from those given in ISO 22232-3.
Who is ISO 22232-2 for? 
 ISO 22232-2 on characterization and verification of ultrasonic test equipment is useful for: 
- Probe manufacturers 
- Testing companies 
- Companies holding tested materials 
- Quality control
- Engineers
 Why should you use ISO 22232-2?  
Probes are a key part of ultrasonic non-destructive testing procedures. They generate high-frequency sound waves. If the probe doesn’t perform properly, flaws smaller than those detected by a standard ultrasonic probe will likely go unnoticed. Not only that but cracks that branch off or have unusual orientations can be missed or improperly sized.
ISO 22232-2 specifies methods and acceptance criteria for the characteristics of probes used for non-destructive ultrasonic testing operating within the frequency range 0,5 MHz to 15 MHz which ensures satisfactory performance.
