The link which failed was a special long one connecting a grab chain to a swivel. It was made from En 14A steel and in continuous use for two years. On one of the fracture faces the chisel edge weld preparation was clearly visible and the crack progression markings present indicated failure was due to fatigue. Macro-etched cross sections showed a lack of penetration and fusion in the weld. Fatigue cracks developed and slowly progressed through the weld metal. Fracture occurred when the remaining area of sound metal was insufficient to support the load. Lack of penetration of this magnitude could be revealed by radiography or ultrasonics but it would be difficult to detect the presence of cracks in course of development from the defects. It would be more prudent to ensure that welded links of this type were free from internal cavities before being put into service.

Failure occurred by fatigue cracking of links from chains which were used to replace the ropes on grabs of the multirope type. In the first example, the links were made from high tensile steel rod. The fracture in the side of the link was duplex in appearance one half of the surface being discolored, indicative of a preexisting crack of the fatigue type, whilst the remaining portion was brightly crystalline, resulting from brittle fracture at the time of the mishap. In the second example, the fracture took place at a similar location adjacent to one of the butt welds situated at the mid-length of the sides. Brinell hardness values confirmed that the link was made from the higher tensile grade of material. The cracks were due to fatigue, there being no indications that the weld was initially defective.