TTT diagram indicates when a specific transformation starts and ends and it also shows what percentage of transformation of austenite at a particular temperature is achieved. Look at figure 1b and 1c.

Isothermal transformation diagrams (also known as time-temperature-transformation (TTT) diagrams) are plots of temperature versus time (usually on a logarithmic scale). They are generated from percentage transformation-vs time measurements, and are useful for understanding the transformations of an alloy steel at elevated temperatures.

TTT diagram stands for “time-temperature-transformation” diagram. It is also called isothermal transformation diagram. Definition: TTT diagrams give the kinetics of isothermal transformations. Davenport and Bain were the first to develop the TTT diagram of eutectoid steel.

The TTT-curve is most useful in presenting an overall picture of the transformation behaviour of austenite. This enables the metallurgist to interpret the response of steel to any specified heat-treatment, to plan practical heat-treatment operations and to control limited hardening or softening and the time of soaking.

TTT diagram is a plot of temperature versus the logarithm of time for a steel alloy of definite composition. TTT diagram indicates a specific transformation starts and ends and it also shows what percentage of transformation of austenite at a particular temperature is achieved.

Time-Temperature-Transformation (TTT) diagram or S-curve refers to only one steel of a particular composition at a time, which applies to all carbon steels. This diagram is also called as C-curve isothermal (decomposition of austenite) diagram and Bain’s curve.

2023年4月28日 · Time-Temperature-Transformation (TTT) diagram is also known as isothermal transformation diagram, sigmoidal diagram, C-curve, orS-curve of the steel. It shows the time needed for austenite to begin to transform, to proceed halfway, and to be completely transformed at any constant temperature in the range covered by the curves.

The Ttt diagram consists of two main components: the time-temperature curve and the transformation curve. The time-temperature curve represents the heating and cooling cycles that the material undergoes, while the transformation curve shows the phases or microstructural changes that occur during these cycles.

Isothermal transformation diagram, also called as TTT diagram, measures the rate of transformation at a constant temperature i.e. it shows time relationships for the phases during isothermal transformation.

3） 通过特定钢种的TTT曲线图，可以（为了得到特定的组织）指导我们在什么温度范围下冷却，需要保温多长时间，对 等温退火 、 等温正火 、 等温淬火 有重要的指导意义，比如指导我们在什么温度下等温，需要等温转变多长时间。 4） 对于冷却速度，可以忽略。 或者说，只保留曲线的横线便可，可以擦掉曲线的斜线部分。 1） 特定钢种的CCT曲线不是确定的，加热温度、形变和晶粒度都有影响，但CCT曲线对指导实践还有有很大的参考意义的。 2） 一般CCT曲线都会注 …