Pass / fail judgment system and pass / fail judgment method for steel pipes, and manufacturing method for steel pipes

摘要

PROBLEM TO BE SOLVED: To take care of a steel pipe which has no room for maintenance when acquiring information on a flaw on the outer surface and the inner surface of the steel pipe and a wall thickness of the steel pipe by using ultrasonic flaw detection and making a pass / fail judgment. We will provide technology that will not be judged as rejected even for steel pipes. SOLUTION: A steel pipe pass / fail determination system that performs ultrasonic flaw detection to acquire information on the outer and inner surfaces of a steel pipe and the wall thickness of the steel pipe and determines the pass / fail of the steel pipe is the presence or absence of defects on the outer and inner surfaces of the steel pipe. It has a defect determination unit that determines the thickness of the steel pipe, a wall thickness determination unit that determines the wall thickness of the steel pipe, and a setting unit that sets the wall thickness determination standard of the wall thickness determination unit. , From the lower limit of the first wall thickness applied when the flaw determination unit determines that there is no flaw and the lower limit of the first wall thickness applied when the flaw determination unit determines that there is a flaw. The lower limit of the second wall thickness, which is also large, is set, and when ultrasonic flaw detection is performed on the steel pipe, the wall thickness is judged according to different judgment criteria depending on the presence or absence of flaws. [Selection diagram] Fig. 1