Double the lifetime of continuous casting rollers with UTP

16 April 2025 |

At the topmost section of the continuous casting line, thermal shock, corrosion, and hot oxidation are most severe, whereas mechanical wear remains relatively low. Consequently, overlay materials with lower hardness but superior corrosion resistance are preferred. With our supermartensitic weld overlay you can double the lifetime of continuous casting rollers protect them for premature wear.

Super martensitic stainless steel offers significantly improved corrosion resistance compared to traditional martensitic types while maintaining acceptable wear performance. To address these challenges, UTP has developed two specialized overlay materials for the initial series of rollers in the vertical section, immediately following the mould in the continuous casting process:

WEARcore 768-S – A cored wire of the 12.5Cr-5Ni-2.5Mo type designed for submerged arc overlay welding.

SOUDOTAPE 430L / RECORD RT 168 – A strip/flux combination of the 12.5Cr-5Ni-2.5Mo type optimized for submerged arc strip cladding.

One of the most aggressive corrosion mechanisms in this environment results from the accumulation of fluorine and alkaline casting powders in the cooling water, known as mould-flux-induced corrosion. To address this issue, soft martensitic stainless-steel overlays are commonly used as a benchmark. The new strip/flux combination underwent extensive testing at the Dillinger Hütte steelworks in Germany to ensure superior performance.

The following performance criteria were established

Enhanced wear resistance in the primary roller section.
Martensite start temperature significantly above room temperature to ensure full transformation.
No impact of base material dilution in the third layer.
Delta Ferrite content below 10% (as per point counting method).
Compatibility with small roll diameters (typically 80-300 mm).
Effective slag release at operating temperatures of 300-350°C.

Results from laboratory and field tests

The super martensitic overlay using RECORD RT 168 / SOUDOTAPE 430L doubled the service life of overlaid rollers in the first segment of the continuous casting line.
Delta Ferrite content in the super martensitic structure of the third layer was maintained below 10% by applying an additional fourth “post-heating layer”.
Slag self-released after just half a turn of rollers with diameters of 80-160 mm.
Laboratory and field tests showed full alignment, confirming real-world applicability.

Soft martensite clad roll

Super martensite clad roll

Conclusion

Through extensive research and testing, the new super martensitic overlay materials significantly enhance the durability and corrosion resistance of rollers in continuous casting lines. With prolonged roller lifespan and improved operational efficiency, these solutions offer a clear advancement in overlay welding technology.

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