Laser cladding the flanks of mill roll grooves.

TO REDUCE THE costs of maintaining mill roll shells, efforts have been made to extend roll shell life and to maintain the roughness of the tips of roll grooves through a season without the need for roll arcing. Techniques for maintaining the diameter of the roll and the roughness of the groove tips have been previously developed, including tungsten carbide-impregnated hardfacing and picots. These techniques for coating the tips of the grooves have a deficiency in that they do not protect the lower flanks of the grooves. As a result, the lower flanks continue to wear away at an unacceptably high rate. This paper reports on the development of a coating to protect the lower flanks and root of the roll grooves. As part of the development, a change to SG iron as a roll shell material is recommended. Plasma transfer arc welding, metal inert gas welding and laser cladding techniques were developed, with laser cladding being the preferred methodology. There remains a need to test the clad surface in service to determine if the benefits from increasing the durability of the groove flanks justifies the cost of the coating.