Control the unknown – Uddeholms monitors slag carry-over

The slag carry-over between process areas is one of the events with major quality and processing influence that still remains uncontrolled in most metal producing plants. An unknown quantity of slag carry-over between process areas will influence on both quality, processing and production.

Quality

Slag carry-over in most cases means to introduce an oxidizing slag into a reducing processing step. The following uncontrolled and undesired reoxidation will influence negatively on the product inner quality, with a likelihood of additional formation of non-metallic inclusions in the final product.

Processing

Introduction of additional oxygen into a process step is detrimental to all operations to be performed under reducing conditions, e.g. alloying and desulphurisation. The effect will be poor performance, low yields, missed targets and/or prolonged processing.

In addition, the existing standardised practice might be designed to handle the worst case slag carry-over scenario, i.e. an costly overkill treatment is performed in most cases.3-cam ex 1

Production

Processing problems eventually lead to production problems due to delays. Any major logistic problem is costly with interrupted casting sequence as maybe the most likely consequence.

Uddeholms monitors deslagging operation

Uddeholms steel plant (Hagfors, Sweden) has recognized the above and monitors the deslagging operation using the LadleSlag technological package.

 – “Keeping previously unknown process variables under control is an important step to obtain a higher and more consistent product quality”, says Rikard Robertsson, process development manager at Uddeholms AB.

Special cameras and image analysis evaluates the operations in order to determine the slag coverage in the ladle during the deslagging process. The image analysis classifies the ladle surface in different phases (metal, thin slag, thick slag) which is represented as a graphical display, see the right hand section of the figure above. The slag coverage is also converted to a value by the LadleSlag vision system. This value is presented to the operator for guidance during the operation and stored in database for future process evaluation.

LadleSlag – more information

Read more about how the LadleSlag system monitors and register the deslagging operations in order to assist the operator and capture data for follow-up and development purposes.

Contact

If you are interested in deslagging monitoring for a more consistent slag-carry over, please contact Mårten Görnerup.