Demand for products manufactured by processing wire rods and round bars, particularly automotive parts, has been remarkably increasing. At the same time, requirements for dimensional accuracy and guarantee of surface and inner quality of such parts have become increasingly diversified and severe.
To meet these requirements, Nippon Steel Corporation has developed and put into practive various advanced inspection equipments and techniques for processing of billets, wire rods and round bars under the policy of "user-in" and "parts-in".
In this paper, newly developed inspection methods for eddy current testing and magnetic leakage flux testing are introduced.
The first is miniaturization of probe, suppression of electro-magnetic noise and self-check by signal observation for eddy current testing. The second is reduction of bar-end dead zone for magnetic leakage flux testing.
These new techniques are put into practive inspection equipments for an "automatic finishing line (AFL) for wire rods" and a "finish production inspection system (FPIS) for round bars".
