Laser cladding of continuous caster lateral rolls: Microstructure, wear and corrosion characterisation and on-field performance evaluation

• Application of laser cladding with nickel base powders to improve roll life.
• Chromium with molybdenum in nickel matrix improves corrosion resistance of clad layers.
• Boron forms hard boride precipitates which contribute to high wear resistance.
• Rolls cladded with high wear resistance powders, perform better in slab caster conditions.

Laser cladding has been used to improve the service life of lateral rolls which experience high temperature wear and corrosion in the zero segment zone of continuous slab caster. Three different compositions of nickel base powders with varying chromium, molybdenum, boron and niobium content with different wear and corrosion resistance properties have been used as cladding consumables. The microstructure of the clad layers shows a two phase cellular dendritic structure, with nickel–chrome dendrites surrounded by hard phases rich in chromium and boron or niobium. Hard precipitates contribute to wear resistance whereas the presence of chromium along with molybdenum in nickel-rich matrix improves resistance to corrosion. Actual performance results suggest that the powder material with higher wear resistance property gives the maximum life when the corrosion conditions are less hostile. In rolls cladded with highest boron and nickel containing powders, the layers were intact, whereas fine cracks and de-lamination was observed in the other rolls.