In-line inspection method, in-line inspection apparatus, and plasma-MIG welding method

摘要

PROBLEM TO BE SOLVED: To provide an in-line test method and an in-line test device with which the in-line inspection can be performed whether or not a through hole capable of realizing the desired strength is formed.SOLUTION: In the in-line inspection method, penetrated holes are subjected to the in-line inspection when executing the penetration-welding of a plurality of superposed workpieces W. The in-line inspection device 10 includes a storage means 12 for storing the calibration curve data indicating the relationship between the lower hole diameter of the through hole formed in the workpiece and the arc voltage of the plasma arc welding for each thickness and each welding condition of the workpieces, and a processing means 13. The processing means 13 performs a penetration detection step S1 of monitoring the arc voltage during the plasma arc welding, and detecting on the basis of the arc voltage whether the plurality of superposed workpieces are penetrated, and a penetrated hole diameter detection step S2 of detecting the prepared hole diameter of the penetrated hole by monitoring the arc voltage, and collating the arc voltage measured after the elapse of the prescribed time from the workpiece penetration with the calibration curve data.