Just wanted to ask one more question to the metalurgical experts, they have been more than helpful! Hope you do not mind:
We have 1/2" rods (I think they are Aquamet 19, Navtec uses that material for this application) that tie the base of the lower stays to the chainplates. These rods are therefore tensile loaded (lengthwise pull). They have been in the boat for 31 years and the boat has been sailed a lot. They look great, however - I do not see any discoloration (due to rust) and no cracks, fissures, crevice corrosion
, IGC, etc.
Is there a time when metal reaches a point where it would be a good idea to replace even if there are no outward signs of fatigue?
Thanks again to all, this thread has been GREAT!!
PS Wichinox has worked well for us in passivating steel. Thanks osirissail.