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Early stage oxidation behavior of Al‐ and Si‐alloyed stainless steels as well as Ni‐based alloys in air at elevated temperatures
Author(s) -
Romu Jyrki,
Sarikka Teemu,
Heikkilä Mikko,
Virkkunen Iikka,
Hänninen Hannu
Publication year - 2018
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201709836
Subject(s) - materials science , metallurgy , oxide , alloy , austenite , austenitic stainless steel , welding , microstructure , corrosion
Several alloys including Al‐alloyed austenitic and ferritic stainless steels, Ni‐based alloy and Si‐alloyed ferritic stainless steel were annealed at 550, 750, and 950 °C for up to 700 h. AISI 347HFG and 10CrMo910 were used as reference materials. Weight gain was measured and the samples were analyzed with SEM/EDS and XRD. Materials having high enough Al‐content performed best due to ability to form a continuous protective Al 2 O 3 ‐oxide layer on their surface at elevated temperatures. Lower Al‐content materials were not able to form a continuous protective Al‐oxide on their surface and suffered from accelerated internal Al‐oxide formation due to alloying elements. Si‐alloying improves the oxidation resistance of the studied materials and their performance was practically in the same level as that of the best Al‐alloyed materials. In Al‐alloyed materials the crystallinity of Al 2 O 3 on ferritic stainless steel weld metal was higher than that on welded and wrought austenitic stainless steels.