At what temperature should refractories be held for 5 hours during oven firing?

The correct temperature to hold refractories for 5 hours during oven firing is 1500F. This temperature is critical because it allows the refractory materials to achieve the necessary physical and chemical stability needed for their intended applications. The firing process promotes the vitrification of certain materials, which enhances their density, strength, and overall performance in high-temperature environments.

At 1500F, many refractories reach an optimal point where binders and other components are sufficiently activated without being overly stressed, which can happen at higher temperatures. Holding the refractories at this temperature for an extended period ensures that the materials are fully cured and can withstand the thermal cycles they will encounter in service.

Overall, proper adherence to the specified firing temperature and duration is vital for ensuring that the refractory linings perform as required in industrial processes, enhancing longevity and efficiency.