A hot rolled, low-carbon steel pot used to melt magnesium alloys leaked, releasing about 35 kg (80 lb) of molten magnesium onto the foundry floor and causing an extensive fire. Due to the fire, the original leakage hole could not be investigated. Samples of the failed pot were polished and etched and were found to be composed of ferrite and pearlite mixtures, as would be expected. However, the sample taken from a location about 75 mm (3 in.) from the hole contained a cluster of unusually large inclusions. By removing the beryllium window from in front of the detector, EPMA spectra were obtained from the inclusions and from the steel matrix. The inclusion spectrum contained primarily iron and oxygen, whereas the matrix spectrum contained primarily iron. X-ray maps were made to show the distribution of iron and oxygen. These results indicated that the inclusions were iron oxide. A similar inclusion at the failure site in the melting pot may have reacted violently with the molten magnesium, causing the leak.

Investigation of alleged corrosion damage to hot-rolled steel during transit requires metallurgical, chemical, and corrosion knowledge. Familiarity with non-destructive techniques and sampling procedures is necessary. A complete record of shipment history is also required, including the purchasing specifications and observations and photographs taken during surveys enroute. A frequent conclusion of such investigations is that the alleged corrosion is of no significance or did not occur during the voyage.