High Temperature Corrosion
Liquid (molten) metal corrosion resistance of stainless steels
Most of the literature on liquid metal corrosion of stainless steels discusses metals such as sodium, potassium, lithium etc. which have been used as liquid metal coolant media in applications such as nuclear power plant.
Sulphidation resistance of stainless steels
For practical considerations, sulphidation in relation to high temperature attack of stainless steels, is more a consideration of the effects of sulphur containing atmospheres, rather than a specific attack mechanism. Both oxides and sulphides may be formed depending on the atmosphere, but generally the resistance to sulphur containing gasses is related to chromium content, in the same way as oxidation.
Oxidation resistance of stainless steels
Oxidation is the formation of oxide rich scale. The scale, once formed, slows down further oxidation, unless it is mechanically removed or cracked, which can happen if the steel deforms under load. In stainless steels, used at elevated temperatures, (up to 1100 deg. C for heat resisting types), this is used to advantage, the scale formed being predominantly chromium rich. The reformed scale layer will prevent further oxidation, but the metal lost in the formation of oxide will reduce the effective strength of the steel section.
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