Abstract:Non-destructive testing of spot weld joints on 1 mm thick SUS304 stainless steel sheet is carried out
by the scanning acoustic microscope(SAM). The C-scan images under different welding process are analyzed, and A-
scan signals in the specific parts of the C-scan images are collected and processed. Then the relationship between
them is analyzed. The diameter of the spot weld is measured through ultrasonic C-scan imagery method. The result
show that SAM can be used to inspect the flaws of spot welded joints. The C-scan images can be used to distinguish
the type of inner defects. When the electrode force is 0. 15 MPa and the welding current is 8 kA or above C-scan ima-
ges can clearly reflect the splash and burnt and so on. The A-scan signals of the specific parts of the ultrasonic C-scan
images are different. The diameter of the spot weld are in the range of 4. 39 to 5. 25 mm based on ultrasonic C-scan
imagery method.
