Phosphide Eutectic Network
A phosphide eutectic network is a brittle, hard ternary eutectic in gray cast iron structures made of iron, carbon, and phosphorus (steadite). It impairs machining.
Physical-Chemical Mechanism of Action
The phosphide eutectic network forms with specific addition rates of iron, carbon, and phosphorus. It consists of a mixed crystal that is both brittle and hard.
Metallurgical Relevance & Welding Risks
This network can cause increased stress strength, making machining difficult. It can also lead to hot cracks and grain refinement issues in the weld if not handled correctly.
Workshop Practice & Action Guidelines
To minimize the phosphide eutectic network, the addition rates of iron, carbon, and phosphorus must be precisely controlled. During welding, slow cooling is recommended to stabilize the structure. The cooling rate should be set so that t8/5 is between 10 and 20 seconds.