What is a2 line in iron carbon diagram?

A2: The temperature where iron looses its magnetism (so-called Curie temperature). Note that for pure iron this is still in the α-phase.

What is the hardest phase of Fe C system?

Martensite
Explanation: Martensite is the hardest phase that can be produced by quenching a steel. Its BHN is about 700. The high rate of strain hardening and dispersion strengthening mechanisms makes the martensite hardest among steel phases.

What is Curie temperature on iron carbon equilibrium diagram?

The A2 temperature is the Curie point when iron changes from the ferro to the paramagnetic condition. This temperature is 769 Deg. C for pure iron, but no change in crystal structure is involved.

What is the difference between pearlite and Ledeburite?

Ledeburite arises when the carbon content is between 2.06% and 6.67%. The pearlite results from the eutectoidal decay of the austenite that comes from the ledeburite-I at 723 °C. During more rapid cooling, bainite can develop instead of pearlite, and with very rapid cooling martensite can develop.

What is fec3?

Cementite consists of iron and carbon compounds combined chemically, having the chemical symbol Fe3C. It is composed of 93% iron and 7% carbon. This compound is brittle, hard and falls under the ceramic classification. Cementite is also known as iron carbide.

What is Eutectoid alloy?

Alloys. Eutectic alloys have two or more materials and have a eutectic composition. When a non-eutectic alloy solidifies, its components solidify at different temperatures, exhibiting a plastic melting range. Conversely, when a well-mixed, eutectic alloy melts, it does so at a single, sharp temperature.

What is critical temperature in iron carbon diagram?

Thus, it is the temperature corresponding to gamma + alpha / gamma phase boundary for hypo-eutectoid steel and is a function of carbon content of the steel, as it decreases from 910 deg C at 0 % C to 727 deg C at 0.76 % C. It is also called the upper critical temperature of hypo-eutectoid steels.

What is iron-carbon diagram?

The Iron-Carbon Diagram: A map of the temperature at which different phase changes occur on very slow heating and cooling in relation to Carbon, is called Iron- Carbon Diagram. Iron- Carbon diagram shows –

What are the various phases of iron carbon equilibrium diagram?

Various phases that appear on the Iron- Carbon equilibrium phase diagram are as under: •Austenite •Ferrite •Pearlite •Cementite •Martensite •Ledeburite Definition of structures:

Why is iron cementite diagram not a true equilibrium diagram?

Iron-Cementite diagram is not a true equilibrium diagram, since equilibrium means no change of phase with time, however long it may be. Graphite is more stable form of carbon.

What is Fe-C equilibrium diagram?

Fig. shows, the Fe-C equilibrium diagram in which various structure (obtained during heating and cooling), phases and microscopic constituents of various kinds of steel and cast iron are depicted. The main structures, significance of various lines and critical points are discussed as under. 1.