JPWO2020074462A5 - - Google Patents

Claims (15)

A method (100) for detecting defects in arc welding, comprising:
During welding, measuring (101) the average weld pool temperature (WP) of the weld (W) by measuring at a single measuring spot using an infrared sensor (2) , said measuring spot substantially surrounds the weld pool (WP) and said infrared sensor (2) is arranged with the welding torch (3) , measuring (101) the average weld pool temperature of the weld;
determining a defect status of the weld by verifying whether the measured weld pool temperature deviates from an expected temperature profile based at least on the measured weld pool temperature; Method (100) . The method (100) of claim 1, wherein the expected temperature profile is determined as an average temperature profile from a plurality of measured welds without defects. 3. The method (100) of claim 2, wherein it is determined that there is no deviation from the expected temperature profile if the measured temperature stays within a defined bandwidth for the expected temperature profile. . calculating the temperature gradient between two different points in time;
The method (100) of any one of claims 1 to 3, further comprising determining a defect status if the temperature gradient exceeds a predetermined temperature gradient threshold. 5. The method (100) of claim 4 , wherein multiple temperature gradient thresholds are defined. 4. The method of claim 1, wherein determining a defect condition further comprises identifying variations in a measured weld pool (WP) temperature and verifying whether the amplitude of said variations is greater than an amplitude threshold. 6. The method (100) of any one of Clauses 1 to 5 . 7. The deviation from the expected temperature profile is determined when the measured temperature profile substantially corresponds to the profile of the defective weld (W) . (100) . said defect condition is at least one of burn-through, porosity, misalignment of said weld, fuse through, unstable weld, gap deviation between workpieces (6) to be joined, or combinations thereof. A method (100) according to any one of claims 1 to 7 , wherein the method (100) relates to one defect. The method ( 100) according to any one of the preceding claims, wherein the weld pool (WP) temperature is measured every 1 to 50 ms, in particular every 5 to 15 ms. The method (100) of any preceding claim, wherein the arc welding is applied to at least one joint of a butt joint, a lap joint, a T-joint, or a combination thereof. The method (100) according to any one of the preceding claims, wherein said arc welding is applied to a workpiece (6) made from at least one of steel, aluminum or alloys thereof. an arc welding torch (3) ;
an infrared sensor (2) arranged with the torch (3) such that the infrared sensor ( 2) is focused on the weld pool (WP) ;
A welding system (1) comprising a controller (8) in data communication with the infrared sensor (2) , comprising:
The measuring spot of the infrared sensor (2) substantially surrounds the weld pool (WP), and the welding system (1) detects defects in the weld according to any one of claims 1-11 . A welding system (1) configured to perform a method (100) for. Welding system (1) according to claim 12 , further comprising a cleaning system for cleaning the infrared sensor (2 ). Welding system (1) according to claim 13 , wherein said cleaning system comprises a nozzle and a high-pressure source for driving fluid towards said infrared sensor (2 ). Welding system (1) according to claim 13 or 14 , wherein said cleaning system comprises a mechanical brush.