CARBON –  Carbon enhances strength but may have an adverse affect on corrosion resistance by the formation of chromium carbides. It is an austenite stabiliser.

CHROMIUM  –  Chromium prompts the formation of ferrite within the alloy structure and is described as ferrite stabiliser.

MOLYBDENM – Molybdenum increases resistance to both local (pitting, crevice corrosion, etc) and general corrosion. Molybdenum and tungsten are ferrite stabilisers which, when used in austenitic alloys, must be balanced with austenite stabilisers in order to maintain the austenitic structure. Molybdenum is added to martensitic stainless steels to improve high temperature strength. 

MANGANESE – Manganese is an austenite former, which increases the solubility of nitrogen in the steel and may be used to replace nickel in nitrogen-bearing grades. 

NITROGEN  – In “austenitic” and “duplex” stainless steels, nitrogen increases the resistance to localized pitting attack and inter-granular corrosion. The low carbon levels in austenitic grades tend to reduce  the yield strength. The addition of nitrogen helps to raise the yield strength levels back to the same level as standard grades

NICKEL – Nickel improves general corrosion resistance and prompts the formation of austenite (i.e. it is an austenite stabiliser). Increasing nickel content beyond 8-9% improves both corrosion resistance  (especially in acid environments) and workability.

TITANIUM – Titanium is the main element used to stabilize stainless steel before the use of AOD (Argon-Oxygen Decarburization) vessels. When stainless steel is melted in air, it is difficult to reducing the  carbon levels. At this high level, titanium stabilize the carbon. Titanium will react with the carbon to form titanium carbides and prevent the formation of chrome carbides, that could affect the formation of the “passive” layer. 

NIOBIUM – Niobium additions prevents inter-granular corrosion, particularly in the heat effected zone after welding. Niobium helps prevent the formation of chrome carbides, that can rob the microstructure  of the required amount of chromium for passivation.