The Time-Temperature-Sensitization (TTS) diagram represents the duration required for the onset of sensitization at various constant temperatures. Figure 1 is an example of a TTS diagram determined for a Type 316 stainless steel.1 The TTS diagram can be used for evaluating the sensitization time for any isothermal heat treatment of steels, but it cannot be used directly to determine the extent of sensitization that can occur when the material is continuously cooled. Even the intersection of a superimposed cooling curve with the isothermal TTS diagram will not indicate whether the steel is sensitized or not, because it does not take into account the effect of time spent in different temperature regions. This report describes a method to predict the extent of sensitization during continuous cooling.
Use is made of the method2 adopted for relating time- temperature-transformation diagram of the carbon steels to their transformation behavior on continuous cooling....
