| Popis: |
The effect of the morphology and distribution of ferrite, especially acicular ferrite in a Widmanstatten structure, on the fracture behaviour of mild steel at low temperatures is discussed in detail. The microstructures of polygonal ferrite, intersecting acicular ferrite and parallel acicular ferrite were obtained using an interrupted cooling procedure, and the different effects on the fracture toughness at low temperature were found. If an intersecting acicular ferrite microstructure is present, then the steel has superior toughness at low temperature in comparison with that of polygonal ferrite. If the microstructure is mainly composed of parallel acicular ferrite, however, the steel toughness is comparable to that of polygonal ferrite. |
