| 摘要 |
A flaw detection apparatus and flaw detection method for automatically detecting the occurrence of a flaw in a mother tube manufactured by rolling a hollow shell using a mandrel mill are provided. A flaw detection apparatus 100 according to the present invention includes a wall thickness gauge 1 which is installed on the exit side of a mandrel mill M and which measures the tube wall thickness in each of the reducing directions of a hollow shell P in the #1-#5 stands of the mandrel mill, rolling load measuring devices 2 which measure the rolling load in the #1-#5 stands, and a decision unit 3 which determines whether there are flaws in the mother tube based on the measured value of the tube wall thickness in each of the reducing directions of the hollow shell P and the measured value of the rolling load in each stand. The decision unit 3 determines that a flaw has occurred in the mother tube when the measured value of the tube wall thickness in any of the reducing direction in the #1-#5 stands locally varies by at least a predetermined amount and the measured value of the rolling load in any of the #1-#5 stands locally varies by at least a predetermined amount.
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