Eccentricity is a zero-tolerance defect in seamless tubing, often caused when the heated solid billet is pierced slightly off-axis. We quantify this defect using the wall thickness (t) in a mathematical ratio:
Eccentricity(%) = tmax - tmin/tavg x 100
To detect this, quality control engineers use continuous Ultrasonic Thickness (UT) gauging around the circumference of the tube as it exits the sizing mill, instantly flagging any sections that deviate from concentricity.