NDT for Austenitic Stainless Steel: The Shift to Phased Array Ultrasonic

For years, industrial radiography has been the standard inspection technique for austenitic stainless steel. But that has changed. Now, more asset owners rely on phased array ultrasonic testing (PAUT) to get faster and more accurate results. 

Just as the field has evolved, there are new ideas about the best methods of nondestructive testing (NDT) for austenitic stainless steel. This article will address how using these cutting-edge techniques can help save money, time, and protect assets.

The Problem With Radiographic Testing for Austenitic Stainless Steel

In many industries, radiographic testing (RT) is still the standard when conducting NDT for austenitic stainless steel. After all, it has been used for years. 

However, there are some primary flaws to this kind of testing, including:

• Insensitivity to misoriented planar defects
• Lack of immediate feedback
• Disruption and compromised safety of other workers

The third is extremely important. Radiography is accompanied by extremely strict regulatory guidelines for non-user proximity. So, when testing is being done, other workers can’t be near and if they are, there are many safety risks involved. That can cause a lot of disruption, especially when it comes to mission-critical facilities. 

Example: Phased array ultrasonic technology (UT) examination of austenitic welds (homogeneous stainless steel welds, dissimilar metal welds) has been applied and formally qualified for in-service austenitic weld inspections for more than 10 years.

As regulations around the world have become more strict, standards and codes have changed to make room for safer, less disruptive NDT testing.