Fe-Ni-Cr alloys

Intergranular corrosion of Fe-Ni-Cr alloys has been the subject of a comprehensive review by Cowan and Tedmon who summarised the various tests used for determining susceptibility (Table 19.3). Of these tests. Nos. 1-5, which are regarded as reliable test procedures by the ASTM, have been incorporated into ASTM A262 1986 Recommended Practice for Detecting Susceptibility to Intergranular Attack in Stainless Steel as follows ... 

M.O. Speidel, Corrosion Fatigue in Fe-Ni-Cr Alloys, Stress Corrosion Cracking and Hydrogen Emhrittlemment in Iron Base Alloys NACE 5, R.W. Staehle, J.H. Hochman, R.D. McCrigh, and J.E. Slater, Ed., National Association of Corrosion Engineers, 1973, p 1071-1080... 

Austenitic Fe-Ni-Cr alloys, which form Cr203 surface layers and have higher creep strength than ferritic aUoys, are used to about 850 °C. 

Another example involves grain boundary Cr depletion (commonly referred to as sensitization) in Fe-Ni-Cr alloys containing interstitially dissolved carbon [45, 46]. Here, Cr depletion occurs upon the formation of Cr23C6 and other carbides [47]. Carbide formation occurs profusely on boundaries as a result of C segregation, heterogeneous carbide nucleation, and fast... 

Che] Chevenard, R, Experimental Investigations on Fe-Ni-Cr Alloys (in French), Trav. Mem. 

Vre] Vrestal, J., Theiner, J., Broz, P., Tomiska, J., Mass-Spectrometric Determination of the Thermodynamic Mixing Behavior of Liquid Ternary Fe-Ni-Cr Alloys , Thermochim. Acta, 319(1-2), 193-200 (1998) (Experimental, Thermodyn., 11)... 

Kak] Kakeshita, T., Sato, Y, Saburi, T., Shimizu, K., Matsuoka, Y, Kindo, K., Effects of Magnetic Field on Athermal and Isothermal Martensitic Transformations in Fe-Ni-Cr Alloys , Mater. Trans., JIM, 40(2), 100-106 (1999) (Experimental, Kinetics, Phase Relations, 13)... 

Carburisation is observed in industrial processes where Fe-Ni-Cr alloys are used in carbonaceous atmospheres at high temperature, especially in the steam cracking of hydrocarbons for ethylene production. Carbon is transferred from the atmosphere into the metal matrix, diffuses inward and causes... 

Clarke, W. L. and Gordon, G. M., Investigation of Stress Corrosion Cracking Susceptibility of Fe-Ni-Cr Alloys in Nuclear Reactor Water Environments, Corrosion, January 1973, p. 1. 

Fe-Ni-Cr alloys are the basis of the 300-series austenitic stainless steels and a large number of industrially important high-tem-... 

Figure 5-23. The melting points of sulfide scales that form on Fe-Ni-Cr alloys (Smith, 1997).

At most conditions, Fe-Ni-Cr alloys are protected against carburization by an oxide layer. However, if this film is destroyed, a catastrophic corrosion can occur (Grabke, H.J. et al 1987). The corrosion starts by pointwise attack, probably by carburization at defects in the oxide layer. The corrosion products can easily be eroded and holes are formed in the material similar to pitting. This type of corrosion is called "metal dusting". Very often, it is observed in a narrow temperature gap. 

Spiedel, M. O. (1977). Corrosion fatigue in Fe-Ni-Cr alloys, Proc. International Conference on Stress Corrosion and Hydrogen Embrittlement of Iron-Base Alloys, Unieux-Finniny, France, June 1973, National Association of Corrosion Engineers, Houston, TX, pp. 1071-1094. 

In this chapter, the basic mechanisms of crevice corrosion are briefly presented but most of the text is devoted to the crevice corrosion of passive alloys, particularly Fe-Ni-Cr-. .. alloys in aerated chloride environments. Phenomenological aspects, the mechanisms of initiation, the conditions of propagation, the modeling, the experimental techniques, and the possibility of prevention are successively described. 

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