Eddy Current Testing in Steel & Primary Metals: What It Finds, What It Misses, and What Governs It
What ET is actually used for in steel & primary metals
Hot and cold mill product inspection uses eddy current for surface defect detection at line speed, where a missed defect becomes a claim.
How ET works
Eddy current testing induces circulating currents in a conductive material and reads the impedance change a discontinuity causes. It needs no couplant and no contact, which makes it the fastest surface and near-surface method available — and, in tube form, the only practical way to screen thousands of heat-exchanger tubes inside a shutdown window.
What ET will not do
What ET will not do: examine non-conductive material, penetrate deeply (the effect is confined near the surface, more so as frequency rises), or produce results anyone can interpret without training — signal interpretation is the whole skill, and lift-off, edge effects and permeability variation all masquerade as indications.
The steel & primary metals assets this applies to
Continuous casters, rolling mills and their rolls, furnace shells and ducting, cranes, and the plate, bar and tube the mill produces.
The damage mechanisms driving the examination
Product soundness — laminations, inclusions and surface defects — alongside plant-side thermal fatigue, wear, and structural fatigue in heavily loaded cranes and mill housings.
What governs acceptance
Product examination runs to ASTM and customer specifications, often inline and automated; plant maintenance examination runs to ASME and jurisdictional requirements. On the method side: ASME Section V Article 8 for tubing; ASTM E243 and E571 for specific product forms; aerospace surface examination runs under NAS 410 with OEM technique requirements. An examination that is technically sound but performed outside the governing regime is not an examination anyone will accept, which is why the code family matters as much as the technique.
How Atlantis delivers ET in this sector
Atlantis mobilises examination teams to your site under Atlantis procedures with ASNT Level III oversight — we do not claim a depot or laboratory in every market, and say so plainly. What you receive is the examination performed to a qualified procedure, findings evaluated against the acceptance criteria your contract names, and records structured to survive a client audit years later.
Eddy Current Testing services · ET training and certification · Steel & Primary Metals NDT training · scope a ET examination.
ET in other sectors
Refining · Petrochemical · LNG · Offshore · Pipeline · Marine & Shipbuilding.