Search results
Results From The WOW.Com Content Network
As the sample is quenched, an increasingly large percentage of the austenite transforms to martensite until the lower transformation temperature M f is reached, at which time the transformation is completed. [1] For a eutectoid steel (0.76% C), between 6 and 10% of austenite, called retained austenite, will remain. The percentage of retained ...
In the iron–carbon system (i.e. plain-carbon steels and cast irons) it is a common constituent because ferrite can contain at most 0.02wt% of uncombined carbon. [6] Therefore, in carbon steels and cast irons that are slowly cooled, a portion of the carbon is in the form of cementite. [ 7 ]
Acicular ferrite steels: These steels are characterized by a very fine high strength acicular ferrite structure, a very low carbon content, and good hardenability. Dual-phase steels: These steels have a ferrite microstructure that contain small, uniformly distributed sections of martensite. This microstructure gives the steels a low yield ...
When some carbon is present, and if cooling occurs quickly, some of the austenite will transform into martensite. Tempering or annealing will transform the martensitic structure into ferrite and carbides. Above about 17% Cr the steel will have a ferritic structure at all temperatures.
It can take the form of ferrite, martensite, or austenite. The binary Fe-Ni system has been investigated for analogic purposes to steel because the presence of nickel in high-alloy steels such as austenitic stainless steels and maraging steels is a key driver for the transition from body-centered cubic ferrite to face-centered cubic austenite. [11]
The large density of dislocations in the ferrite present in bainite, and the fine size of the bainite platelets, makes this ferrite harder than it normally would be. [4] [5] The temperature range for transformation of austenite to bainite (125–550 °C) is between those for pearlite and martensite. In fact, there is no fundamental lower limit ...
Further excessive heat-treatment brings about the decomposition of the martensite and reversion to austenite. Newer compositions of maraging steels have revealed other intermetallic stoichiometries and crystallographic relationships with the parent martensite, including rhombohedral and massive complex Ni 50 (X,Y,Z) 50 (Ni 50 M 50 in simplified ...
The main differences in composition, when compared with austenitic stainless steel is that duplex steels have a higher chromium content, 20–28%; higher molybdenum, up to 5%; lower nickel, up to 9% and 0.05–0.50% nitrogen. Both the low nickel content and the high strength (enabling thinner sections to be used) give significant cost benefits.