Weld Metal Microstructure (cont)
- Ferrite-Carbide Aggregates (FC)
- high heat input welds with low cooling rate
- polygonal ferrite rejects carbon
- equiaxed ferrite/carbide or pearlite aggregate produced
- Polygonal ferrite
- grain boundary ferrite (GF)
- intragranular ferrite (PF) - not significant quantities
- nucleated at austenite grain boundaries in high heat input welds
- low strength and can reduced toughness