NDT inspection

Inspections of the internal brazed joint areas have long been problematic. Prior to implementation of the AWS C3.7 brazing specification, it was required only on “Grade A” joints and rarely invoked on the engineering drawings.

This fundamentally changed with adoption of the AWS C3.7. Both destructive and non-destructive inspections are required on “Class B” brazing. Although the internal quality requirements are generous for Class B joints the real problem is with interpretation of the test results and the costs driven by this testing. It usually is not a large issue on flat plate type of assembles with a single axis braze joint such as vacuum brazed liquid cold plates. The major issue is complex salt bath brazed enclosures and heat exchanger chassis with many joints in all axis and multiple levels. The 2011 revision adds a new application of ultrasonic of braze joints, AWS C3.8, however this does not address the root problems for the contract brazer.

For a greater discussion on the ways in which we can help you with this issue please contact us.