Select NDT according to the likely defect and service risk
Nondestructive testing is not one fixed package for every casting. Alloy, section thickness, defect orientation, accessibility and consequence of failure determine the method, acceptance standard and production stage.
Typical methods
- Visual examination for accessible surface condition and obvious indications
- Liquid penetrant testing for surface-breaking indications on suitable nonporous surfaces
- Ultrasonic testing where material, section and geometry provide a technically suitable examination path
- Radiographic examination when the specification, geometry and target discontinuity make it appropriate
Dimensional and surface-roughness measurement are complementary inspection activities; they are not substitutes for NDT.
Define the acceptance requirement
The drawing or purchase specification should identify test zones, governing standard, sensitivity, sampling level, personnel qualification and reporting. Machining may expose previously hidden material, so the test stage matters as much as the method.