Intergranular Corrosion
Intergranular corrosion is a selective attack along the grain boundaries of a metal, primarily caused by the precipitation of chromium carbides. This leads to localized wear and reduces the service life of the material.
Physicochemical Mechanism of Action
Intergranular corrosion occurs when chromium carbides precipitate at the grain boundaries of a metal. This precipitation leads to a depletion of protective elements such as nickel and cobalt. The resulting gaps are sites for corrosive agents to concentrate and damage the material.
Metallurgical Relevance & Welding Risks
Intergranular corrosion can cause localized wear and reduce the service life of the material. It can also increase susceptibility to cracking and fracture, especially under mechanical stress. This can lead to premature failure of components or machine parts.
Workshop Practice & Action Guidelines
To avoid intergranular corrosion, it is important to adhere to correct welding techniques and parameters. This includes careful cleaning of the weld surface, using appropriate protective coatings, and following proper cooling times. For heavily stressed parts, it is also advisable to use additional corrosion prevention methods such as flame spraying or painting.