Inconel Grain Boundary Corrosion Susceptibility
Inconel grain boundary corrosion susceptibility is the susceptibility of Inconel alloys to intergranular corrosion due to carbide precipitation at grain boundaries under unfavorable thermal conditions. Titanium or niobium modifications reduce this effect.
Physical-Chemical Mechanism of Action
Inconel alloys contain nickel and can develop carbide precipitates such as cobalt carbide or niobium carbide. These precipitates accumulate at grain boundaries and can lead to intergranular corrosion when the alloy is subjected to unfavorable thermal cycles (e.g., high temperatures with rapid cooling).
Metallurgical Relevance & Welding Risks
This intergranular corrosion can lead to cracking and deformation, especially in weld areas. Susceptibility increases with high temperature exposure and rapid cooling. This can seriously compromise the mechanical strength of components.
Workshop Practice & Action Guidelines
To minimize Inconel grain boundary corrosion susceptibility, the following measures should be taken:
• Use targeted alloy modifications with titanium or niobium.
• Keep thermal cycles during fabrication and welding as constant as possible.
• Avoid rapid cooling after welding by using controlled cooling.
• Monitor temperature exposure throughout the process and keep it within specified limits.