In ferrous alloys, annealing is usually accomplished by heating the metal beyond the upper critical temperature and then cooling very slowly, resulting in the formation of pearlite.
42.
Ferrous alloys are usually either " full annealed " or " process annealed . " Full annealing requires very slow cooling rates, in order to form coarse pearlite.
43.
As a consequence a rapidly cooled steel may reach a temperature where pearlite can no longer form despite the reaction being incomplete and the remaining austenite being thermodynamically unstable.
44.
The end product below 0.8 % carbon content is a pearlite-ferrite mixture, and that above 0.8 % carbon content is a pearlite-cementite mixture.
45.
The end product below 0.8 % carbon content is a pearlite-ferrite mixture, and that above 0.8 % carbon content is a pearlite-cementite mixture.
46.
When viewed through a magnifying lens, the nioi appears as a sparkly line, being made up of many bright martensite grains, which are surrounded by darker, softer pearlite.
47.
For instance, in the iron-carbon system, the austenite phase can undergo a eutectoid transformation to produce ferrite and cementite, often in lamellar structures such as pearlite and bainite.
48.
If the steel is cooled slowly the transformation will agree with the equilibrium predictions and pearlite will dominate the microstructure with some fraction of proeutectoid ferrite or cementite depending on the chemical composition.
49.
HSLA steels are also more resistant to rust than most carbon steels because of their lack of pearlite the fine layers of ferrite ( almost pure iron ) and cementite in pearlite.
50.
HSLA steels are also more resistant to rust than most carbon steels because of their lack of pearlite the fine layers of ferrite ( almost pure iron ) and cementite in pearlite.
