HEARTH ROLL FOR HEAT TREATMENT EXCELLENT IN RESISTANCE TO BUILD-UP

摘要

PURPOSE:To improve the build-up resistance of a hearth roll for heat treatment, by forming a Si-contg. metal layer on the surface of the metal roll by telescoping a sintered sleeve or spraying. CONSTITUTION:An annular sleeve formed by sintering metal powder containing 15% or more Si in a reducing or inert atmosphere is telescoped onto a metal roll. Powdery metal containing 15% or more Si or a cored wire containing it may be directly sprayed onto the surface of the metal roll by gas or plasma sparay, instead. The metal layer forms a SiO2 film on the surface even at extremely low oxygen partial pressure, and alleviate the formation of build-up while suppressing the reaction of iron powder or iron oxide with the roll surface.