Using EMATs to measure the wall thickness of hot galvanizing kettles

摘要

The authors demonstrate that a single EMAT send-receive system can be used to measure the wall thickness of steel galvanizing kettle at their normal operating temperatures, which are in excess of 450℃. The kettles are typically fabricated from 50 mm-thick steel, the steel reacts with the liquid zinc to form an alloy layer which grows slowly resulting in thinning of the vessel wall. The kettles can be safely operated until a reduction of around 40% in the wall thickness has occurred and this normally takes at least five years. Studies indicate that it is possible to measure the steel wall thickness to within ±0.5 mm and also to observe changes within the alloy layer.