TESTING FOR WELD INTEGRITY

Destructive Testing

Destructive testing is performed on all prototype welds and per customer specifications.

Non-Destructive Testing

Ultrasonic inspection is used regularly to ensure weld integrity. This test is performed per customer specifications.

As the name states, Destructive Weld Testing involves the physical destruction of the friction welded components. A variety of testing methods can be employed to evaluate the weld's characteristics.

Sampling inspections of production welds are performed to:

• Qualify weld performance
• Troubleshoot using failure analysis
• Research inspection processes to improve or validate current testing methods

One test involves examining a cross-section of the weld.

Using a macro etch test (and depending on the base material(s) joined in the weld), a mild acid mixture is applied to the cross-section surface. The resultant etching provides an excellent study of the internal structure of the weld, which is also helpful in detecting welding problems.

Additional tests may be applied to validate ductility, soundness of welded joints, tensile strength or any presence of slag inclusions or weld discontinuities within the entire length of the weld.

Depending on the characteristics to be inspected, we use various destructive test methods for friction welds:

• Bend tests:
  Free bend, Guided bend, Longitudinal bend, Transverse bend
• Etch test
• Hardness tests:
  Brinell hardness, Rockwell hardness
• Impact test
• Nick-break test
• Tensile test
• Torque test

Non-destructive testing involves inspection of welded components by subjecting them to the required service conditions to determine suitability.

The non-destructive tests are designed to reveal defects that may impair service performance. They will not break or alter the structure or appearance of the friction welded piece.