Evaluation of Welding Quality using Servo-Gun Displacement Data for Field Spot Welding

다국어 초록 (Multilingual Abstract)

To ensure quality of spot welds, various nondestructive testing methods are used in addition to destructive testing methods, such as tensile shear tests and metallographic examination. Specifically, ultrasonic evaluation is widely used for measuring the nugget size in resistance spot welding. This study focuses on determining the possibility of establishing a standard to evaluate the quality of resistance spot welding in real time using servo-gun displacement data. Two-, three, and four-layered materials, including galvanized steel and hot stamped steel, were used in the experiment. To obtain a welding lobe diagram, we performed resistance spot welding three times under the same conditions, and secured the servo-gun data, which change depending on the expansion and contraction of the material. The strength and fracture mode data obtained from a tensile shear test were compared with the servo-gun displacement data, and the results were analyzed. The results evidently confirmed that the displacement data of the electrode of the medium-sized C gun clearly correlated with the tensile strength data of welding. However, the displacement data of the large C gun exhibited a slightly low correlation, presumably because of a mechanical issue. Furthermore, it was predicted that the results of this study could be used for real-time welding quality evaluation with minimal additional costs.

목차 (Table of Contents)

• Abstract
• 1. Introduction
• 2. Experimental method
• 3. Experimental results and discussion
• 4. Conclusion
• Reference