What is CCT diagram of steel?
A continuous cooling transformation (CCT) phase diagram is often used when heat treating steel. These diagrams are used to represent which types of phase changes will occur in a material as it is cooled at different rates.
What does CCT and TTT diagram stand for?
CCT. TTT. CCT stands for Continuous cooling transformation which is a continuous cooling curve. TTT stands for time-temperature transformation which is basically a time-temperature transformation curve. CCT curves are useful to obtain different metastable products by controlling the rate of cooling.
What is the difference between CCT and TTT?
The primary difference between TTT diagrams and CCT diagrams is that TTT diagrams examine the progress of transformation as a function of time, at a fixed temperature. CCT diagrams examine the progress of transformation as a function of changing temperature.
What is the full form of TTT diagram?
Isothermal transformation diagrams (also known as time-temperature-transformation (TTT) diagrams) are plots of temperature versus time (usually on a logarithmic scale).
How many types of CCT diagrams are there?
How many types of CCT diagram are there? Explanation: There are two types of continuous cooling transformation diagrams which can be drawn. In the two type, some factors are changed to obtain a different curve.
What is shown by TTT diagram?
Isothermal transformation diagrams (also known as time-temperature-transformation (TTT) diagrams) are plots of temperature versus time (usually on a logarithmic scale). Time-temperature-precipitation diagrams and time-temperature-embrittlement diagrams have also been used to represent kinetic changes in steels.
What is TTT diagram for eutectoid steel?
At temperatures just below eutectoid temperature, austenite decomposes into pearlite; at lower temperatures (600 deg C) sorbite is formed and at 500 – 550 degree C troostites is formed. If the temperature is lowered from 500 deg C to 220 deg C acicular troostite or bainite is formed.
What is bainite structure?
Bainite is a plate-like microstructure that forms in steels at temperatures of 125–550 °C (depending on alloy content). A fine non-lamellar structure, bainite commonly consists of cementite and dislocation-rich ferrite.
Which type of curves are used to construct TTT diagram?
Explanation: S curve, C curve isothermal diagram and Bain’s curve are all names given to time temperature transformation diagrams.
How do you create a TTT diagram?
On quenching in water austenite transforms to martensite. Transformation of austenite is plotted against temperature vs time on a logarithm scale to obtain the TTT diagram. The shape of diagram looks like either S or like C. temperature due to low driving force or nucleation rate.
What is bainite for?
One of many applications for bainitic steel is in railway transport for highly strength and wear resistant rails. Rail steel must be designed to be able to resist plastic deformation, wear, rolling contact fatigue, bending stress and thermal stress during rail welding process and rails resurfacing.
