Intercrystalline Corrosion
Chromium-nickel austenitic stainless steels are prone to this form of corrosion when they are welded and subsequently in contact with certain types of corrosive media. When heated within a temperature range of 450-800oC precipitation of the chromium carbides takes place at the grain boundries in the area of the weld and these areas not longer have the protection of the chromium on the peripneries of the grains. This type of corrosion is also known as Weld Decay and Intergranular Corrosion. The most common way to avoid the problem is to select a grade of steel that is very low in carbon i.e. 0.03% or less, or one that is stabilzed with niobium or titanium.
