Input control: Identification of bad quality material, e.g. rolled wire (drawing lines for thick wire), bar, tube or pipe
Quality control: Detection of defective areas in test material and assignment of test piece to a quality category
Process control: Monitoring of production lines to avoid scrap, e.g. through transport mechanisms causing periodic defects
Final inspection: Assurance of crack-free material
Typical defects: Laps, holes, longitudinal cracks, tension cracks from annealing (wire), damage from transport devices (tube, bar, wire), damage through defective drawing lines (wire) or rollers (hot rod)
Inline testing of tube, bar, and wire takes place in the production line at the time the material is produced. It assures that the material is free of cracks, holes and other material defects or periodic defects as even small surface defects can lead to defective end products, critical in items such as surgical instruments. Eddy current testing is extremely successful in detecting surface defects at various stages during the production process. For the best test results, encircling testing is used together with rotational testing. This testing method is also highly recommendable for hot environments such as hot rolled bar or hot rolled ferrous rod production.
Air conditioner tubing is inspected inline after extrusion. An encircling coil tests for outer surface defects and checks that the walls of the interior chambers are intact. It is spec
