Oxidation of stainless steels (AISI 304 and 316) at high temperature. Influence on the metallic substratum

Abstract

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Thermodynamic and Kinetics Aspects of High Temperature Oxidation on a 304L Stainless Steel

“…Reflections of the bulk phases (austenite and ferrite) are present in all samples. The presence of a ferrite phase is somehow unexpected in an austenitic steel, even if it has been already reported in the literature [3] In order to perform quantitative analysis of phase fraction, a XRD measurement with higher acquisition time, and hence with a higher signal-to-noise ratio, was performed for a samples annealed in industrial-like conditions (that is 2 hours at 1050 °C and 0.087 atm of oxygen partial pressure …”

“…Samples were cut from the core of the rods and prepared in the form of parallelepiped of about 3x3x1 mm 3 . All the surfaces were finished with a 1200 emery paper.…”

“…Several models for the oxide growth on stainless steels are present in the literature [1][2][3][4][5]. They can be summarized considering the formation of a chromia (Cr 2 O 3 ) layer at low temperatures, which acts as a protective barrier against further oxidation.…”

Time-Dependent Crack Growth Thresholds of Ni-Base Superalloys

“…From Eq. [20], it is obvious that material [48] 41.61 200 [71] 96 to 131 [70] NbC Fcc a o = 4.470 [51,52] 93.91 340 to 400 [54] 3.0 to 4.0 [54] Cubic a o = 10.63 [51,53] 1201.2 325 to 334 [57] 7.1 [56] Ni 3 Al Cubic a o = 3.57 to 3.60 [48][49][50] 45.5 178 [58] 30 [ [64] 257.59 362 [54,59,60] 3.5 [54,59,60] TiO 2 tetragonal a o = 3.784; c o = 9.514 [65] 136.27 270.7 [59,60] 2.49 [59,60] …”

“…Hcp a o = 3.607; c o = 3.925 [66] 44.22 125 [61] 1.5 CoO cubic a o = 4.254 [67,68] 75.44 189 [66] 1.12 [62] NiO cubic a o = 4.173 [66,68] 72.67 230 to 260 [62,63] 1.5 [62] CrO cubic a o = 4.1 [69] 68.92 -1.5 NiCr 2 O 4 cubic a o = 8.32 [70] 573.9 106.6 [62] 0.57 [62] FeO cubic a o = 4.334 [72] 81.41 130 [74] 1.7 [75] a-Fe 2 O 3 rhombohedral a o = 4.99; c o = 13.61 [73] 338.6 219 [74] 1.7 [75] c-Fe 2 O 3 cubic a o = 8.40 [73] 591.92 208 [74] 1.7 [75] parameters that enhance K th also reduce the crack growth rates at K > K th by reducing the near-tip crack driving force. The beneficial effects of transformation toughening, however, diminish with increasing K levels above K th as the relaxed crack-tip stress field approaches the K-field, as shown in Figure 9.…”