Zinco Service: Using ultrasound to inspect cracking risk of steel kettles

 At hot dip galvanizing plants, zinc is melted in giant steel kettles. The temperature of the molten zinc is +450 degrees centigrade, and in the extreme heat the inner surface of the steel kettles gradually dissolves into the zinc. In theory approximately 1.8 millimetres of the five-centimetre steel surface dissolves each year, but in practice even more can dissolve. Maintaining the condition of the giant steel kettles is therefore a priority. Even the smallest kettles can hold around 200 tonnes of zinc. Should a crack appear in the kettle and molten zinc be released onto the factory floor, the costs of shutting down production and making repairs can be enormous.

Inspecting the condition of a steel kettle previously required pumping the zinc out or dismantling the equipment around the kettle. In practice this entails several days of work during which the kettle cannot be used for production.

“We are now trying a new method in which the thickness of the steel can be measured using ultrasound through the molten zinc. The time required for such an operation is less than a single work shift. This effectively eliminates the need for long shutdowns,” says Pekka Poutiainen from the Ylivieska plant of Caverion Industria, the first to test the method in Finland.

Like Caverion Industria, Teknotyö Kuumasinkitys Oy also ordered an inspection of its kettles in Ylistaro and Järvenpää. Measurements were taken in three locations and took just three days altogether. The logistics expertise of Algol Chemicals played a key role in successfully keeping to the tight schedule. A specially manufactured container is used to transport the KID - Kettle Inspection Device to the location.

Zinco Service srl and Algol Chemicals teaming up to carry out an inspection at the Teknotyö Kuumasinkitys plant in Ylistaro, Finland. Pictured from left to right: Enrico Foglia and Dan Alexandru from Pako Zinco and Juri Kongojev from Teknotyö. The Demag crane used by Teknotyö was supplied by Algol Technics.

Ask more information from Niko Mikkola, tel. +358 50 501 4578