Intergranular corrosion
The Intergranular corrosion ( IK ) is a form of corrosion which can occur in most alloys at corresponding conditions. It is also called "grain disintegration". The corrosion runs along the grain boundaries .
When alloyed with chromium steels , the material contained in the connecting chromium upon heating (such as when welding ) with the carbon to chromium carbide ( ). As a result, the chrome is no longer available for corrosion protection (formation of a passive layer ) in the heated area. This occurs especially with higher carbon steels.
In the case of corrosion-resistant steels, the carbon is bound by niobium or titanium to form niobium or titanium carbide (stabilized steels) or the carbon content is reduced ( IF steel , or LCS = low carbon steel or ELC = extra low carbon, C content ≤ 0 , 03%) counteracts IC susceptibility: These measures prevent the harmful reduction of the chromium content along the grain boundaries, i.e. increase IC resistance.
literature
- Karl-Helmut Tostmann: Corrosion. Causes and Avoidance. Wiley-VCH Verlag, Weinheim 2001, ISBN 3-527-30203-4 .
- Helmut Kaesche: The corrosion of metals. Third edition. Springer Verlag, Berlin / Heidelberg 1990, ISBN 3-540-51569-0 .
- Elsbeth Wendler-Kalsch, Hubert Graefen: Corrosion damage theory . Springer Verlag, Berlin / Heidelberg 2012, ISBN 978-3-642-30431-6 .
Web links
- Horst Heinrich: The corrosion of metals using the example of intergranular corrosion (IC). (PDF) OTH Regensburg , 2001, accessed on April 22, 2014 (PDF; 1.25 MB).
- Corrosion in stainless steels (accessed September 10, 2018)
- Corrosion resistance of stainless steel (accessed on September 10, 2018)
- Types of corrosion - Part 2 (accessed September 10, 2018)
- Corrosion Resistance (accessed September 10, 2018)