Why are TTT diagrams called isothermal temperature diagram?As far as I know the temperature variation is plotted with the variation of time in a TTT diagram. Then why do we call it "isothermal".What is so constant about the temperature?
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$\begingroup$ They are there to show you what happens while holding a sample at fixed temperature for different times. For non-isothermal conditions they are not particularly useful as normally presented. $\endgroup$– Jon CusterCommented Jul 24, 2019 at 16:46
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2$\begingroup$ “Put up in a place / where it's easy to see / the cryptic admonishment / T.T.T. / When you feel how depressingly / slowly you climb, / it's well to remember that / Things Take Time.” (Piet Hein, T.T.T.) $\endgroup$– andselisk ♦Commented Jul 24, 2019 at 20:22
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They are two names for the same procedure. A steel is heated to a temperature in the austenite range then quenched/quickly cooled to some specific temperature. Held at that constant ( isothermal) temperature ( T) for a specific time (T) then quenched to room temperature for examination of the transformation (T) products. You may be thinking of CCT ; continuous cooling diagrams ; where a steel sample is austenitized then continuously cooled at some specific rate. Then examined for transformation products. The results can have similarities depending on alloy content , etc.
