ASTM Test Bar (Test Block)

The ASTM Yoke Test Block is a specialized tool designed to verify the performance and effectiveness of magnetic particle testing (MPT) yokes. It serves as an essential reference standard for evaluating magnetization strength and flaw detection capability in various industrial and military applications.

This test block features seven artificial flaws (side-drilled holes) of varying depths, simulating subsurface defects to ensure reliable and repeatable test results. It is compact, portable, and suitable for onsite inspections, making it a valuable asset in non-destructive testing (NDT) environments.

The ASTM Yoke Test Block is commonly referred to as an MPT Test Bar and is used to verify proper yoke function under both AC and DC magnetization conditions:

• AC Yoke Testing: A minimum of three visible lines must be detected.

• DC Yoke Testing: A minimum of five visible lines must be observed.

This test block is designed to meet or exceed industrial and military standards for artificial test specimens, ensuring accuracy and consistency in magnetic particle inspection (MPI) applications.