Several glass wool insulation sections from a heat-treat furnace showed visible, but only cosmetic discoloration. EDS showed the presence of silicon, aluminum, and oxygen in the nondiscolored region, and these elements are consistent with glass wool. Relatively high levels of chromium and nickel were detected in the discolored area, along with lower amounts of iron, manganese, sodium, calcium, cobalt, and sulfur, in addition to the surrounding glass wool elements. Results of this limited evaluation showed the discoloration was caused by the presence of elevated levels of chromium, nickel, and aluminum. The visual appearance, along with the EDS findings, suggested...
S.J. Suess, Discoloration of Furnace Insulation, ASM Failure Analysis Case Histories: Steelmaking and Thermal Processing Equipment, ASM International, 2019, https://doi.org/10.31399/asm.fach.steel.c9001623
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