MAC’s Robotic ERW Phased Array Echomac® PA TW is an operator friendly system for detecting weld zone defects in tube and pipe due to scarf or problems with the welding process. Designed to meet API 5L, API 5CT and other global standards, this Robotic PA TW tester can detect N10 and N5, ID and OD longitudinal notches, and 3.2mm through drilled holes and half wall drilled holes, among others. Phased Array provides a unique advantage for weld zone inspection as the operator does not need to make any adjustment as long as the weld is within the system’s specified radial position. Electronic scanning ensures that the entire weld zone is covered without the need for mechanical movement or operator adjustment.
The PA probe is placed concentric to the tube or pipe. Performing normal incidence beams results in thickness measurements that are processed and displayed in B-scan and C-scan views resulting in a real-time image showing the weld profile. Visualizing the weld profile quickly alerts the operator to any issues with the scarfing process.
The same test that is used for scarf monitoring can be used for flaw evaluation for laminar defects in the HAZ (heat affected zone). By adding positive and negative angle beam cycles the system can detect longitudinal OD/ID defects typically found in the welding process. All the scans are performed sequentially, utilizing only one array.
The test head consists of a spring loaded transducer holder utilizing a liquid coupling (usually mill coolant), attached to a molded test shoe. To change for a different diameter, simply unlatch the transducer module and replace the test shoe with one sized for the new diameter. Test shoes for the customer’s required sizes are supplied with the system. The robot which holds and manipulates the test head is controlled entirely by an intuitive HMI using a push button panel. The robot’s concentric position, with respect to the tube during testing, is fixed and no adjustment is needed when changing test shoes. Any adjustments for the transducer settings are handled electronically so no manual changes are required.
This system provides operator friendly setup and run modes. The operator is alerted by visual and audible alarms. In addition, the signal is sent to the PLC for the down-line paint marker. The system is integrated into the customer’s plant by using signals from the mill PLC to ensure it quickly retracts the test head to prevent any damage after a cut-out or open seam is detected.