Nondestructive testing for castings is most useful when the inspection question is clear. A buyer may need to detect surface-opening cracks, examine internal soundness or verify a particular region after machining. No single method answers every question equally well, and a request for NDT without further definition leaves too much uncertainty.

Separate surface questions from internal questions

Liquid penetrant testing is used for discontinuities open to an accessible, suitably prepared surface. Magnetic particle testing applies to ferromagnetic materials and addresses surface and near-surface indications. Their suitability depends on the material and the condition of the area being examined.

Radiographic and ultrasonic methods can address internal examination, but geometry, material structure and the expected discontinuity affect their usefulness. Method selection should be made with qualified inspection personnel for the actual component.

Define the region and the inspection stage

A requirement covering an entire rough casting differs from one focused on a machined sealing region. Access and surface preparation may change during production. State when examination is required so the supplier can plan it at the appropriate point in the route.

For example, machining may expose a region that was previously below the surface. If that region is critical, the inspection plan should account for the delivered condition rather than assume an earlier examination answers the same question.

A test method is not an acceptance criterion

The order should identify the applicable procedure or standard and the required acceptance basis. Detection of an indication does not automatically establish whether the component is acceptable; that decision depends on the governing requirements.

ASNT’s manufacturing NDT overview describes the roles of different methods. For a purchase order, the inspection scope must be translated into component-specific requirements rather than left as a general reference to nondestructive testing.

Make the records traceable to the supplied parts

Agree the required report and identification arrangement. Results should connect to the correct drawing revision, lot and examined region. Any repair and re-examination obligations need to follow the approved requirements.

Tousin Metal can discuss casting inspection scope during quotation. Defining the question first makes NDT a useful acceptance tool and helps suppliers price the actual examination obligation accurately.