| Industry: |
Shipping |
| Specimen Description: |
ship anchor |
| Material: |
KSC 40 high carbon cast steel |
| Environment: |
seawater, river water |
| Background: |
A ship's anchor failed due to complete separation just above the flukes while hosting the anchor in a US river. The river temperature at the time of the anchor failure was approximately 25C.
|
| Time in Service: |
Unknown |
| Findings: |
The anchor fracture was flat, brittle and contained chevron markings. After polishing a section at the fracture initiation point, it became evident that the anchor casting had been repair welded at some time. Cracks were following the heat affected zone (HAZ) of the weld at the surface. Observation of the microstructure showed that the cracks were intergranular, following prior austenite grain boundaries in the martensitic matrix. The maximum hardness in the cracked area was measured at Vickers 653. |