Degree of graphitization
The degree of graphitization indicates how much free graphite is present in a cast iron alloy structure. A high degree leads to softer, but less tough materials.
Physical-Chemical Mechanism of Action
Graphitization is the process by which carbon is precipitated in cast iron alloys and remains as free graphite in the structure. This process depends on additives such as silicon and the melting process.
Metallurgical Relevance & Welding Risks
A high degree of graphitization can lead to a softer alloy, which reduces toughness and strength. This increases the risk of cracking and distortion under mechanical stress. With too high graphite content, the weld can also become coarser and its hardness reduced.
Workshop Practice & Instructions
To achieve an optimal degree of graphitization, the carbon content and silicon content in the alloy should be precisely controlled. When welding highly graphitic alloys, careful control of cooling steps is required to avoid cracking. Recommended cooling time: 10-20 minutes per cm³ of material.