PDFAll furnace typesRunning heat-up curves correctly
Why the first days decide over years of service life.
Only in the PDFExample curves for ramming mix, castable and brick lining with hold points and ramp rates
To the articleInspect and maintain2 min
The heat-up curve: why the first few days decide years of service life
The complete relining is finished — and now begins the phase that decides years of service life: the controlled heat-up.
The complete relining is finished — and now begins the phase that decides years of service life: the controlled heat-up.
Why this step is so critical
- Once set, refractory castable contains both free and chemically bound water. Heating up too quickly generates steam pressure inside the structure — the risk ranges from spalling to destruction of the new lining before the furnace has ever produced anything.
- Every plant is started up along a material-specific heat-up curve: defined heating rates and holding stages in the critical temperature windows in which the moisture escapes in a controlled way. Depending on the material and wall thickness, this takes two to five days.
- The process is monitored by temperature measurement and fully documented — the curve actually followed forms part of the as-built documentation and is the basis for the 12-month warranty.
Whoever saves two days during start-up pays for them several times over later — with shorter campaigns and unplanned shutdowns. A properly executed heat-up curve is the cheapest lifespan insurance there is.
At a glance
2–5 days
duration of a controlled first heat-up
Documented
heat-up curve as part of the as-built documentation
Further reading
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