Comparative study of high temperature oxidation behaviour in AISI 304 and AISI 439 stainless steels

Abstract

This work deals with a comparison of high temperature oxidation behaviour in AISI 304 austenitic and AISI 439 ferritic stainless steels. The oxidation experiments were performed between 850 and 950 °C, in oxygen and Ar (100 vpm H2). In most cases, it was formed a Cr2O3 protective scale, whose growth kinetics follows a parabolic law. The exception was for the the AISI 304 steel, at 950 °C, in oxygen atmosphere, which forms an iron oxide external layer. The oxidation resistance of the AISI 439 does not depend on the atmosphere. The AISI 304 has the same oxidation resistance in both atmospheres, at 850 °C, but at higher temperatures, its oxidation rate strongly increases in oxygen atmosphere. Concerning the performance of these steels under oxidation, our results show that the AISI 439 steel has higher oxidation resistance in oxidizing atmosphere, above 850 °C, while, in low pO2 atmosphere, the AISI 304 steel has higher oxidation resistance than the AISI 439, in all the temperature range investigated

Development of a Methodology for Structural and Mechanical Characterization of Extended Sheets Made from Stainless Steels

“…The 304A stainless steel had a complex austenitic microstructure, strongly strain hardened, which is in accordance with the literature 14,15,17 . It is observed a high density of slip lines and twinned regions that darken the etched microstructure.…”

“…It is observed that the 1010, 439, 444A and 410D steels, have predominantly ferritic microstructure, as expected [8][9][10][11][12][13][14][15][16] . However, there is a significant difference in the morphology …”

“…The 304A stainless steel has a good ductility, good resistance to stress-corrosion in environments containing chloride, good resistance to pitting corrosion and is hardenable by mechanical forming [13][14][15][16][17] . As there are no international standards accepted for mechanical tests on extended sheets, this work has a original character, regarding the experimental methodology and the fact that it presents the possibility of materials substitution in extended sheet manufacturing.…”

Wetting and interactions of Ag–Cu–Ti and Ag–Cu–Ni alloys with ceramic and steel substrates for use as sealing materials in a DCFC stack

“…However, in higher temperatures and in high oxygen partial pressures, Cr 2 O 3 and Fe oxides can exist simultaneously and the growth of the oxides is controlled by kinetic factors. As the interdiffusion coefficients of Cr in the ferritic steels is about 10 times higher than in the austenitic steels, this Fe-O layer is not formed in the Crofer steels [19]. During the wetting experiment of SS316L by Ag, this very brittle Fe-O layer is formed, and as the systems cool down it causes the formation of cracks in the Ag-steel interface which leads to the complete separation of the droplet from the substrate.…”

“…The grain boundary diffusion coefficients for the Mn, Cr and Fe ions of the steel through the Cr 2 O 3 layer are in the order [33] and so the faster diffused Mn migrate towards the interface reacting with the Cr. This Cr-Mn reaction zone acts as stabilizer to the Cr-O protective layer of the steel and increases the oxidation resistance of the steel [19]. Diffusion of Cr and Fe in the liquid phase created inclusions of a Fe-Cr alloy that can be found in the interface but also inside the droplet (Fig.…”