| Abstract: | Kinds of crack-producing corrosion and their significance for the availability of components of chemical plants. Interor transcrystalline cracks in metallic components of chemical plants can occur under the combined influence of mechanical stress and corrosion. Since they usually remain unrecognized before the occurrence of visible damage – leakage of a vessel or fracture of a structural part – such crack-producing corrosion processes are greatly dreaded. Based on differences in the mechanism of the process of damage, one distinguishes two groups, i. e. stress corrosion cracking (SCC) and corrosion fatigue (CF). SCC stands for an interaction between local corrosion attack and quasi-static tensile stresses (load- and/or residual stresses). CF means a combination of mechanical stresses differing in time and corrosion. Hydrogen induced SCC is a special kind of crack corrosion, initiated by atomic hydrogen absorbed in a metal. The paper describes the different systems of SCC and CF, the forms of failure, the parameters, and the possibilities of avoiding damages, especially emphasizing their significance in practice. |
