Weld Metal Microstructure
Principal microstructural types
- acicular ferrite
- (AF) small feathery laths of ferrite with low aspect ratio
- transformation occurs at relatively high temperature (~800oC)
- Ferrite with aligned carbides (AC)
- martensite, austenite and carbides at lath boundaries
- parallel laths with higher aspect ratio
- poor toughness and low strength welds