Search results
Results From The WOW.Com Content Network
For a eutectoid steel (0.76% C), between 6 and 10% of austenite, called retained austenite, will remain. The percentage of retained austenite increases from insignificant for less than 0.6% C steel, to 13% retained austenite at 0.95% C and 30–47% retained austenite for a 1.4% carbon steel. A very rapid quench is essential to create martensite.
The iron-chromium phase diagram shows that up to about 13% Cr, the steel undergoes successive transformations upon cooling from the liquid phase from ferritic α phase to austenitic γ phase and back to α. When some carbon is present, and if cooling occurs quickly, some of the austenite will transform into martensite.
TTT diagram of isothermal transformations of a hypoeutectoid carbon steel; showing the main components obtained when cooling the steel and its relation with the Fe-C phase diagram of carbon steels. Austenite is slightly undercooled when quenched below Eutectoid temperature. When given more time, stable microconstituents can form: ferrite and ...
Austenitization means to heat the iron, iron-based metal, or steel to a temperature at which it changes crystal structure from ferrite to austenite. [3] The more-open structure of the austenite is then able to absorb carbon from the iron-carbides in carbon steel. An incomplete initial austenitization can leave undissolved carbides in the matrix ...
300 series stainless steels are the larger subgroup. The most common austenitic stainless steel and most common of all stainless steel is Type 304, also known as 18/8 or A2. Type 304 is extensively used in such items as cookware, cutlery, and kitchen equipment. Type 316, also known as A4, is the next most common austenitic stainless steel.
Duplex stainless is widely used in the industry because it possesses excellent oxidation resistance but can have limited toughness due to its large ferritic grain size, and they have hardened, and embrittlement tendencies at temperatures ranging from 280 to 500 °C, especially at 475 °C, where spinodal decomposition of the supersaturated solid ...
In carbon steel, cementite precipitates from austenite as austenite transforms to ferrite on slow cooling, or from martensite during tempering. An intimate mixture with ferrite, the other product of austenite, forms a lamellar structure called pearlite. The iron-carbon phase diagram
Martensitic stainless steels can be high- or low-carbon steels built around the composition of iron, 12% up to 17% chromium, carbon from 0.10% (Type 410) up to 1.2% (Type 440C): [8] The chromium and carbon contents are balanced to have a martensitic structure.