Three industries (power generation, paper and steel) have been faced with finding means to protect and extend the operating cycles of their boilers due either to the fuel they burn, method of combustion, and/or the impact of environmental regulations. A common method to protect these tube surfaces is to use weld overlays. In coal-fired boilers with tangential or wall mounted Low NOx burners, corrosion resistant overlays are being used to lower wastage rates caused by the reduced environment above the burners. Also, in some cases high ash levels have resulted in the need for erosion resistant overlays around soot blower openings and sloped walls. Cyclone, fluidized-bed, and basic oxygen furnace (BOF) boilers use ovedays to resist particle erosion. Black liquor recovery boilers and waste-to-energy boilers use overlays to resist corrosion damage from the fuels being burned. As an improved overlay alternative, the laser cladding process: (1) produces a very low dilution overlay
(typically 5%) to obtain the optimum benefits of the alloy being deposited even at a low thickness of 0.020" (0.5mm) and (2) increases the selection range of materials since the process can utilize powders .