Abstract: Boiler tube studs of composite construction, particularly for protecting waterwall tubes in pulp mill recovery boilers. The studs include an inner solid cylindrical core of a material having thermal conductivity sufficient to provide proper heat transfer to the boiler tubes during operation, and an outer cylindrical sleeve of a material resistant to destructive conditions within a boiler during operation, such as chemical attack and abrasion. The sleeve surrounds the cylindrical surface of the core, but leaves an end surface of the core exposed. The core may be made of low carbon steel, and the sleeve of stainless steel. In order to avoid melting of the stainless steel sleeves when the studs are welded to the tubes, the cylindrical sleeves do not extend all the way to the attachment end such that axial gaps are defined where the sleeves do not cover the cylindrical surfaces of the cores.