The structure and stability of austenite in Cr−Mn−Ni steels containing nitrogen
We have defined the concept of steel "austeniticity." This term indicates the degree to which the austenite structure is stable and to what extent it is possible to change the composition of the steel (increase the concentration of ferrite-forming elements or decrease the austenite-forming elements) or subject the steel to deformation without inducing transformation of the austenite.
We investigated the effect of the variation of the chemical composition of Cr17G9ANi4 steel and showed that the standard composition of this steel is strongly austenitic. The concentration of the austenite-forming elements (N, Mn) can be decreased without inducing the occurrence of δ-ferrite and without rendering the steel susceptible to the formation of martensite under the effect of deformation.
Because of the high degree of austeniticity of Cr17G9ANi4 steel it can be alloyed with Nb (up to about 1%) and Mo (up to about 3%) without inducing the appearance of the ferritic component.
KeywordsNitrogen Austenite Martensite Austenite Structure Standard Composition
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