Graphite flakes
Graphite lamellae are free carbon precipitates in gray cast iron that act as notches in the structure and lead to high vibration damping. However, they significantly reduce toughness and ductility of the material.
Physicochemical Mechanism of Action
Graphite lamellae are microscopic carbon surfaces in cast iron that develop during cooling. These lamellae consist of free carbon and can occur in various sizes and shapes.
Metallurgical Relevance & Risks in Welding
Graphite lamellae impair the mechanical properties of cast iron as they act as notches in the structure. This leads to reduced toughness and ductility, making the material more prone to cracking. During the welding process, these lamellae can further develop or coarsen, which can affect the quality of the weld.
Workshop Practice & Instructions
To minimize the growth of graphite lamellae, it is important to ensure careful cooling of the cast iron. This can be achieved by using cooling water or special cooling plates. When welding cast iron with high graphite content, it is advisable to ensure slow and controlled cooling of the weld to avoid the formation of additional lamellae.