Critical crevice corrosion temperature
The critical crevice corrosion temperature is the minimum temperature at which crevice corrosion starts in a narrow gap under specified test conditions. It is typically lower than the critical pitting temperature of the same material.
Physical-Chemical Mechanism of Action
The critical crevice corrosion temperature (CCCT) is the temperature above which corrosion initiates in tight crevices under specified test conditions. This process is triggered by the chemical reaction between the metal and the surrounding medium.
Metallurgical Relevance & Welding Risks
At temperatures above the CCCT, corrosion can occur in narrow crevices, such as in joint gaps or weld crevices. This leads to component degradation and can cause premature shutdown or cracking.
Shop Practice & Action Guidelines
To avoid the CCCT, careful attention must be paid to the ambient temperature during welding and assembly. At temperatures above the CCCT, special corrosion prevention measures are required, such as applying corrosion inhibitors or using metals with higher corrosion resistance.