Effect of Nitrogen on Blister Growth Process during High Temperature Oxidation of Steel

Abstract

Blistering occurs when oxide scale swells during oxidation at high temperatures. Blistered scale causes surface defects when rolled. The present study investigated the effect of nitrogen on blister growth when steel is oxidized at high temperatures, and drew the following conclusions. Atmospheric conditions before oxidation affect blister growth. Blisters nucleate but do not grow, when a steel sample is held in Ar gas or in vacuum before oxidation. Blisters inflate when a steel sample is held in N2 gas before oxidation. The gas inside the grown blisters is mainly N2 gas. The steel surface is nitrided in N2 gas at high temperatures. It is deduced that the steel surface is nitrided before oxidation, and the nitrogen component causes blister growth upon its release as N2 gas at the scale/steel interface.

The influence of high-temperature oxidation on the phase distribution of metal substrate in duplex stainless steel

“…In the case of low-alloy steel, Kondo et al reported that the gas permeability depends on the type of scale structure consisting of Fe. Oxides of FeO and Fe 3 O 4 have gas permeability, but Fe 2 O 3 does not [10]. However, it is unknown whether the gas permeability of the scale depends on its composition such as Cr 2 O 3 and MnO.…”

Role of Hematite Formation on Blister Generation during High Temperature Oxidation of Steel

“…6) At the growth stage of blister, N2 alone was also found to have an effect on blister growth. 7) These results suggest that the pressure of the CO, CO2, and N2 gases generated at the scale/steel interface has a significant influence on blister initiation. We assume that spaces are already formed at the scale/steel interface before blister initiation.…”

“…1,2,5) It was suggested that not only CO and CO2, but also N2, play a role in the blistering phenomenon. 6,7) No previous research has been reported on the role of scale structure on for blistering. Therefore, the present research is focused on the effects of the oxygen content in the atmosphere and scale structure on the blistering phenomenon.…”

The Influence of Preliminary Deformation Treatment on the Hardening and Quality of the Nitrided Surface of Austenite Stainless Steel

“…Подобный механизм образования газовых полостей и блистеров в приповерхностном слое наблюдается и при имплантации больших доз ионов инертных газов (гелия или аргона) или при отжиге нержавеющей аусте-нитной стали 12Х18Н10Т, предварительно облученной низкоэнергетическими альфа-частицами [27]. Пузыри из газообразного азота могут формироваться также под растущей оксидной пленкой, возникающей на поверх-ности азотированного слоя в результате высокотемпера-турного окисления [28]. Вызванное большими концен-трациями азота и количества ε-фазы «вспучивание» поверхностного слоя обусловливает его выкрашивание при последующей механической обработке, что должно отрицательно сказаться на износостойкости азотиро-ванного слоя [29].…”