The results for the clad surfaces were very similar to the standard series with individual values lying within the scatter band over the whole test range. All the welds failed in the fracture toughness K1c mode along the line of the weld bead. On mechanical testing, the clad welds showed similar cracking to that of the standard series with clear cracking along the weld bead. This is caused by the lower ductility of the clad zones, which can lead to brittle failure. The strong ductility differences between the weld and heat affected zones of the base metal had a small impact on the cracking mainly along the diameter of the weld at which the crack initiated.
The results for the small welds resemble those that we obtained for the large welds in the standard series: A characteristic failure, which differs only in the cut off size, with clear cracking within the ductility limits along the weld bead. The small welds showed clearly the transition from the welded zone to the heat affected zone of the base metal, where there was a large difference in hardness between the zones. On mechanical testing of these samples, the welds failed along the same line, showing the typical tensile cracking mechanism. 7211a4ac4a