What do you call holes, grooves, or notches introduced into a reference standard for quality levels?

The term for holes, grooves, or notches introduced into a reference standard for quality levels is "an artificial discontinuity." These features are intentionally created during the manufacturing or calibration of standards to simulate the presence of defects or to establish specific criteria for testing and evaluation. They serve as controlled references that allow technicians to assess the sensitivity and response of non-destructive testing methods to different types of discontinuities.

In contexts such as ultrasonic or eddy current testing, artificial discontinuities are useful because they provide a consistent benchmark against which real-life scenarios can be compared. This is essential for ensuring that the testing devices are properly calibrated and can reliably detect actual defects in materials. Natural discontinuities, on the other hand, occur without human intervention and are inherent to the material.

Understanding the distinction between artificial discontinuities and natural ones is crucial for quality control and assurance in various industries, ensuring that materials meet required safety and performance standards.