QUANTITATIVE QUALITY INDICATORS (QQI)
Artificial flaw shim standards for MPI increase productivity by minimizing magnetizing “shots.” Placed on part surface to verify field direction and relative strength. Particularly useful for balancing multi-directional fields. Approved by major specifications including ASTM E 1444 (replaced MIL-Std-1949A).
For more quantitative work, three concentric circular flaws of differing depth, .0004″, .0006″, and .0008″ (20%, 30%, 40%).
