Abstract
The delamination cracks and its effects on the fracture of pipeline steel were investigated. The results show that the three-dimensional stress state is prerequisite for delamination crack and the strength distribution of material influences the form and direction of delamination crack. The delamination cracks are produced on the weak interfaces in the material by the tensile stress perpendicular to them before main crack propagation. The occurrence of delamination crack and its direction depend on the three-dimensional stress fields and strength distribution of material near the crack tip or notch root. The delamination cracks change the form of the crack and influence the three-dimensional stress fields of the crack tip; this can influence the fracture obviously. The delamination cracks of the fracture through wall thickness make the effective thickness decrease and the delamination cracks of surface crack are perpendicular to the direction of fracture propagation direction. The more energy is needed to produce delamination crack, the three-dimensional constraint of crack tip decreases, the effective thickness decreases or main crack tip is blunt. These factors all make fracture more difficulty, the toughness of the material will be improved.
| Original language | English |
|---|---|
| Pages (from-to) | 311-318 |
| Number of pages | 8 |
| Journal | Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research |
| Volume | 21 |
| Issue number | 3 |
| State | Published - Jun 2007 |
| Externally published | Yes |
Keywords
- Delamination crack
- Fracture
- Metallic materials
- Pipeline steel