How should high-temperature oxidation be specified for industrial heating elements?

Whether high-temperature oxidation is acceptable for industrial heating elements depends first on the sheath material ceiling and the actual atmosphere, since air, flue gas or sulphur- and chlorine-bearing media sharply accelerate scaling and shorten life. Selection should relate watt density, tube diameter and continuous running hours to the true wall temperature, keeping it well below the material limit and leaving more margin at higher watt density. Confirm the maximum allowable wall temperature against medium dew point and flow velocity to avoid local overheating, and ensure adequate mounting clearance and support to prevent deformation or short circuits. Acceptance should reproduce field thermal cycling, logging resistance, insulation resistance, heat-up curve and oxide scale thickness, and check protection rating, mounting clearance and temperature control such as thermocouple position, over-temperature cut-off and start-up current limitation; request corrosion data from the supplier when needed.