Metal wire
Non-destructive eddy current testing for high-speed free-cutting steels
Trafilerie Assi Spa has specialized in the cold drawing of high-speed free-cutting steel bars and coils since the early 1970s, supplying material for machining applications across the metalworking industry.
Surface quality requirements have become increasingly stringent, particularly in sectors such as automotive, where the pursuit of the so-called “zero-defect” objective extends throughout the production chain. To address these demands, Trafilerie Assi has developed extensive expertise in the supply of steels inspected using eddy current non-destructive testing (NDT-ET), investing in dedicated surface inspection equipment and continuously upgrading its existing systems.
How does eddy current testing work?
Eddy current non-destructive testing allows inspection of the steel surface without altering or damaging the material. The technology works by inducing electrical currents in the material being inspected. Any surface discontinuity causes a variation in the resulting signal, allowing the inspection system to detect potential defects.
This technology can identify a wide range of surface defects and discontinuities and can be used on Trafilerie Assi products with round, hexagonal, and square cross-sections.
The type of discontinuity detected may vary depending on the stage at which it occurs. During hot rolling, for example, defects may include cracks and scale-related imperfections, while subsequent cold drawing can result in defects such as stress cracks, grooves, and scoring.
Material handling is another critical stage that requires careful monitoring, as improper handling can cause abrasions and indentations on the product surface.
The ability to detect these discontinuities is particularly relevant when bars are intended for high-productivity machining operations or for supply chains subject to stringent quality specifications.
Defectomat and Circograph: eight dedicated inspection lines
Trafilerie Assi carries out these inspections using Defectomat stationary-head equipment and Circograph rotating-head systems.
The company currently operates a total of 6 Defectomat inspection lines and 2 dual-inspection lines combining Circograph and Defectomat systems.
Round, hexagonal and square bars: inspected size range
Trafilerie Assi’s inspection capabilities cover a wide range of geometries and dimensions. The company can guarantee and certify the following size ranges as eddy current inspected:
- Round: 5 to 90 mm
- Hexagonal: 6 to 70 mm
- Square: 6 to 40 mm
For surface quality classification, the company refers to the European standard UNI EN 10277-1:2000. The maximum guaranteed surface quality is Class 2 for square and hexagonal bars and Class 3 for round bars, extending to Class 4 for ground and peeled products.
Through its investments in advanced inspection systems, Trafilerie Assi combines its long-standing expertise in cold drawing with specialized capabilities in the supply of inspected free-cutting steels.
For more information about the company’s product ranges and the available options for inspected material, please visit the Trafilerie Assi website using the contact details provided.
