V2 Blocks

V2 Blocks (IIW Type 2 Block): Quick UT Verification

The V2 Block, officially known as the IIW Type 2 Calibration Block (International Institute of Welding), is a standardized reference specimen primarily used in Ultrasonic Testing (UT). It is a smaller, more portable version of the IIW Type 1 (V1) block, designed for quick, on-site verification and functional checks of UT equipment and probes during an inspection shift.

Design and Features

The V2 Block is typically made of steel or aluminum and is significantly more compact than the V1 block, making it ideal for field use. Its key features are precisely engineered to verify critical inspection parameters:

• Arc/Radius: Features a $25\ \text{mm}$ radius section. This is used to check the refracted angle ($\theta$) and the Beam Index Point (BIP) (the sound exit point) of an angle beam transducer.

• Side-Drilled Hole (SDH): Contains a $3.0\ \text{mm}$ diameter side-drilled hole. This provides a reference reflector used to set or verify the sensitivity and amplitude linearity of the UT instrument.

• Straight Beam Reference: Contains material thicknesses for quick checks of the straight beam probe’s zero offset and range calibration.

• Through-Hole: A diameter through-hole is sometimes included for certain distance calibration checks.

Primary Applications

The V2 Block is indispensable for maintaining confidence in the UT system’s performance throughout an inspection campaign:

1. Quick Angle Verification: Allows the operator to rapidly confirm that the angle beam probe is refracting sound at the correct angle .

2. Beam Index Point (BIP) Check: Essential for ensuring the flaw location measured by the instrument is accurate.

3. Time-Base Linearity: Verifying the sweep on the screen correctly represents distance.

In summary, the V2 Block allows the inspector to quickly verify the calibration set up earlier on the larger V1 block, ensuring the equipment remains compliant with inspection standards like ASTM E164 throughout the day.