Automated method for butt weld inspection and defect diagnosis

An automated method for non-destructive inspection and evaluation of a butt weld used to join two coils of sheet metal end-to-end, the method comprising the steps of:

• transmitting electronically from a welding apparatus to a data acquisition unit of a non-destructive weld inspection system information pertaining to the welding apparatus and to the process by which a butt weld has been made by the welding apparatus;
• storing on the data acquisition unit the information transmitted from the welding apparatus to the data acquisition unit;
• positioning near the butt weld a transport apparatus of the non-destructive weld inspection system, having a first and a second electromagnetic acoustic transducer (EMAT) attached to and housed within the transport apparatus;
• scanning the butt weld with the transport apparatus while the first EMAT produces an ultrasonic SH shear wave which is transmitted through an end portion of a first sheet metal coil toward a weld joining the end portion of the first sheet metal coil to an end portion of a second sheet metal coil and while the second EMAT receives an ultrasonic SH shear wave which is reflected from the butt weld and which produces an electrical signal in the second EMAT;
• transmitting to the data acquisition unit the electrical signal produced in the second EMAT;
• recording on the data acquisition unit the electrical signal produced in the second EMAT;
• analyzing in the data acquisition unit the electrical signal produced in the second EMAT;
• signaling the presence of a defect in the weld when an analysis of the electrical signal produced in the second EMAT indicates a defect;
• communicating electronically with the welding apparatus to reperform the butt weld and/or to alter the process for making one or more subsequent butt welds when the analysis of the electrical signal produced in the second EMAT indicates a defect.