Imaging spot weld inspection using Phased Array technology – new features and correlation to destructive testing

Vogt, Goeran; VOGT Ultrasonics GmbH; Germany

Vogt, G.; VOGT Ultrasonics GmbH; Germany
Mußmann, J.; VOGT Ultrasonics GmbH; Germany
Vogt, B.; VOGT Ultrasonics GmbH; Germany
Stiller, W-K.; Hochschule Hannover; Germany

ID: ECNDT-0243-2018
Download: PDF
Session: Ultrasonic Inspection 2
Room: G2
Date: 2018-06-13
Time: 10:50 - 11:10

This presentation focuses on the suitability of using imaging ultrasonic phased array technology (PAUT) for the inspection of resistance spot welds. In this study 2- and 3- layer joints with a single sheet thickness of 0.7 up to 3 mm are tested using PAUT as well as the destructive hammer and chisel testing with a metallographic section analysis. The results of the testing methods are correlated and tested for deviations. This analysis will especially discuss the measurement accuracy of the nugget diameter. Additionally the precision of the attenuation due to structural transformation of high-strength steel and the residual wall thickness in the welded area of aluminium PHAsis is providing optional.
The phased array inspection of the welded spots was realized with the PHAsisone inspection device. With 121 ultrasonic elements in an 11 x 11 matrix, a physical resolution better than 0,35mm is achieved. More than 700 measuring points are documented per spot weld as a fast electronic scan image. For the adaption of the probes to the test part, the water path is used with the reliable bubbler technique or a fixed rexolite wedge. Like the conventional spot weld inspection with only one ultrasonic element, up to 500 to 800 spots can be inspected per shift. The software supports the spot weld testing by scan plans for programmed parts or by a “free testing mode”, where the user can test various spot welds, detached from set inspection plans.
For the test plan preparation, often all spots of the specimen are manually tested in an optimized order. The “free testing mode” offers detachment and simultaneously the possibility to store all data, sequences and evaluations. By using PHAsismanager PC-Software, the collected data can be transferred into a new test plan for the following serial inspection. This final test plan then can be synchronized with relevant inspection devices and easily be realized by a user with much less ultrasound know-how.