Decarburizing and Coating Line (DCL) for Silicon Steel Strip

Tenova, with its over 40 years of experience, is the only company with the competence and knowledge, of the entire multi-stage thermal process chain, which is required for the production of grain-oriented electrical steel strip.

The final cold rolled GO silicon steel strip needs to be annealed in a continuous process line for primary recrystallization and decarburization to a level below 30 ppm. The decarburization of the silicon steel strip is necessary to make the steel ageing-resistant, so that the magnetic properties are stable even after long term operation as transformer core material. Besides the high requirement on accurate and reliable temperature profiles during annealing, soaking and cooling the atmosphere control in the DCL is essential.The atmosphere control, mixing and humidification system is the part with the highest degree of complexity in this annealing furnace.

The Cleaning Section is a key process component to remove the residual Rolling oil and Iron Fines. This helps in minimizing the Furnace roll contamination and thus the frequency of pitting defect on the strip surface

The Tenova cleaning section is equipped with the special high efficiency electrolytic cleaning unit (HTMCD) properly combined with spray alkaline cleaning, high efficiency-quick maintenance brushing units ( brush to brush type) to enhance the strip cleanliness and allowing to reduce of 20-25% the electrical consumption.

The annealed strip coming from the Furnace is coated with a MgO slurry layer that is dried in a dedicated oven (generally a gas infrared type is used) and cooled before recoiling on Tension reel. This heat resistant MgO layer is will avoid coil wrap sticking in the following step of production cycle in batch annealing and also it will contribute to the formation of the insulation glass film on strip surface.