Application of innovative fibre optical thermal monitoring at CC-billet mould for improved control of product (FOMTM)

The aim of this pilot research was to develop and operate a better control of initial solidification at meniscus level to enhance surface quality of as-cast products. Innovative fibre optical temperature measuring technique was applied into a 185 mm × 185 mm billet mould of a six strand caster. Forty temperature measurement positions were spread onto four faces of the mould. Two moulds were equipped and about 340 heats are measured. No significant indications of wear caused on the harsh environment at the caster could be observed, neither after the revamping procedure. To operate the FOTS measuring system online analysing software was developed. This provides visual information on the behaviour in the mould, especially the current thermal profile and alarm value for unwanted occurrences. The stored data could also be classified later. A collection of data regarding as-cast billet surface quality was done. Analysis of the cast samples and relation to FOTS data are showing the dependence of temperature behaviour and longitudinal crack formation and further surface defects. The installed alarm value has been demonstrated to be useful to identify and control separately billets that could suffer from quality problems due to excessive mould powder additions. The usefulness of this technology could be demonstrated for comparisons of both mould powders and strategies of addition. After alignment with real measurement data the offline working heat transfer model indicates a good accordance within the meniscus region. This technology is also transferable to other casters or place where conclusions can be obtained from temperatures measurements.