The analysis of spot welding joints of steel sheets with closed profile by ultrasonic method

• Ultrasonic method allows to control steel body sheets and closed profile joints.
• Impulses from the area of specific joint are similar to sheet–sheet joint impulses.
• High costs of ultrasonic equipment are balanced by its applicability.

Resistance spot welding is widely used in the fabrication of vehicle bodies and parts of their equipment. The article presents the methodology and the results of non-destructive ultrasonic testing of resistance spot welded joints of thin steel sheet with closed profile. Non-destructive test results were verified on the basis of welded joint area after destructive testing. The obtained results were used to develop an assessment technique for spot welded joints of closed profile with steel sheet, which could be used in factories employing such joints. In addition, the article makes comparison between the costs of the developed assessment technique and currently used destructive method.