The decomposition of austenite to ferrite or cementite begins at the equilibrium phase boundary of austenite/ (ferrite austenite) or austenite/(cementite austenite) in binary Fe–C phase diagram. The temperature values on the phase boundaries of austenite/(ferrite austenite) and austenite/(cementite austenite) at a certain carbon content are called Ae3 and Acm temperatures of the steel, respecti...

Many steels contain substitutional solutes which have a strong affinity for carbon or nitrogen. Such steels can be hardened by heat treatment which induces the precipitation of fine alloy carbides. Examples of such carbides include MX, 2 73 , 6 and 236 , where M stands for a mixture of iron and substitutional solute atoms and X stands for interstitial solute atoms. In practice, the heat treatme...

A systematic study of the influence of plastic deformation and low temperature ageing on the carbon Dislocation Enhanced Finkelshtain Rosin Effect (DEFREIC) in austenitic alloys of Fe-Ni, Fe-Ni-MO, Fe-Mn-A1 and Fe-Cr-Ni systems with different carbon content is reported. The experiments prove that after plastic deformation at room temperature the FR effect is transformed into DEFREIC. nith both ...

It has been possible in recent times to make large quantities of steels in which the controlling scale is 20 nm or less, i.e., comparable to that of carbon nanotubes. The mechanical properties of such steels are abnormal. For example, in some cases the ductility vanishes as the strength increases, whereas in others the ductility almost entirely consists of uniform plastic strain. Some of the st...

LOW-TEMPERATURE CARBURIZATION is a gaseous carburization process performed at atmospheric pressure, at temperatures where the kinetics of substitutional diffusion are very slow. Low-temperature carburization hardens the surface of austenitic stainless steels through the diffusion of interstitial carbon, without the formation of carbides. The surface must be activated, by modification and remova...

*Member of ASM International arburizing has been a popular method for obtaining a unique balance of properties in steels for many years. Steels with low carbon contents are characterized by good toughness and good ductility, but low strength and low wear resistance. By locally increasing the carbon content at the surface, followed by heat treatment to produce a very high hardness in this layer ...