Sootblower nozzle tip B-12 failed due to thermal fatigue likely from repeated quenching when the high temperature sootblower nozzle tip was exposed to the relatively cold steam/condensate in the blowing media. Higher operating temperatures were likely due to location of sootblower and/or poor shielding/retractable mechanism. Higher carbon was detected than specified maximum. Higher carbon content likely played a role in the failure to propagate the cracks at a faster rate. The cracks may have followed the inter-dendrites due to lack of ductility. Higher carbon in the steel likely diminished the fatigue strength due to lack of ductility. Relatively higher hardness was observed than typical range