Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Austenite
Summary
Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K (727 °C); other alloys of steel have different eutectoid temperatures. The austenite allotrope is named after Sir William Chandler Roberts-Austen (1843–1902); it exists at room temperature in some stainless steels due to the presence of nickel stabilizing the austenite at lower temperatures.
From alpha iron undergoes a phase transition from body-centered cubic (BCC) to the face-centered cubic (FCC) configuration of gamma iron, also called austenite. This is similarly soft and ductile but can dissolve considerably more carbon (as much as 2.03% by mass at ). This gamma form of iron is present in the most commonly used type of stainless steel for making hospital and food-service equipment.
Austenitization means to heat the iron, iron-based metal, or steel to a temperature at which it changes crystal structure from ferrite to austenite. 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.
For some iron metals, iron-based metals, and steels, the presence of carbides may occur during the austenitization step. The term commonly used for this is two-phase austenitization.
Austempering
Austempering is a hardening process that is used on iron-based metals to promote better mechanical properties. The metal is heated into the austenite region of the iron-cementite phase diagram and then quenched in a salt bath or other heat extraction medium that is between temperatures of . The metal is annealed in this temperature range until the austenite turns to bainite or ausferrite (bainitic ferrite + high-carbon austenite).
By changing the temperature for austenitization, the austempering process can yield different and desired microstructures.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.