What do we call metal blocks that contain holes to simulate discontinuities?

The term "reference blocks" is used to describe metal blocks that contain holes or other artificial discontinuities designed to simulate flaws for the purpose of testing and calibrating ultrasonic testing (UT) equipment. These blocks serve as a benchmark against which the performance of the testing system can be evaluated. By using these calibrated artifacts, technicians can ensure that the equipment is properly detecting and sizing discontinuities like cracks or voids in actual materials.

Reference blocks are an essential aspect of quality control in NDT, as they allow for consistent testing and validation of ultrasonic instruments across various applications. They are typically made of the same material as the components being inspected, with features that mimic potential defects, enabling accurate assessments during real inspections.