Originally Posted by
Casey302
Here’s one theory -
“The combined effects of stress and corrosion can result in a special type of failure known as Stress Corrosion Cracking (SCC). This arises under a particular set of circumstances for a given alloy: specific alloy condition plus specific corrosive media and sufficient local tensile stress. Chloride induced cracking of stainless steels, caustic cracking of plain carbon steels and ammonia damage to copper alloys are typical examples of this problem.
SCC is believed to be nucleated at pitting damage sites and develops under the action of local tensile stresses as a highly branched network of fine cracks. At each crack tip the combined action of the tensile stress and specific ions in the corrosive media cause continual crack propagation with little evidence of local deformation.
Stress corrosion cracking presents an especially difficult problem, since not only is it highly localized but it can occur in environments that are merely mildly corrosive to the material. The damaging concentration of the harmful ions in that environment may be quite small and difficult to detect and, even in the absence of applied stress, residual stresses in a structure can often be of a sufficiently high level to cause SCC and failure in service.
In a given situation the time of exposure needed to cause SCC failure depends on the stress intensity at any pre-existing or developed crack tip. The concentration of stress at the tip of a sharp crack or flaw can be quantified in terms of the Stress Intensity Factor, K1. It determines the growth rate of SCC cracks for a specific alloy environment combination. Catastrophic failure of a component will occur when this factor reaches a critical value, the Fracture toughness of the material, K1C. This enables the determination of allowable defect size in design to avoid failure under given loading conditions.”
Your fine old Wade & Butcher has likely been exposed to over 100 years of corrosive influences and in all probability the stress induced in the polishing & honing process was sufficient to begin the failure.
There is obviously no way of telling how far the micro-cracking permeates the metal or how much will have to be removed to find that perfect edge, but I wish you good luck!