Phases in Heat Affected Zone
Martensite formation promote by increasing carbon or alloy content (higher hardenability)
- Produces a brittle HAZ
- Large austenite grain size promotes formation
Ferrite with M-A-C is the main microstructural constituent near the weld in C-Mn steels
- this may be aligned (AC) or non-aligned (FN)
Intragranular Widmanstatten ferrite formed with high heat input and slow cooling rates
- similar to casting microstructure
- weak