Hmm! it appears we have A4 (316) SS failing on a sulphate crag? It’s time to measure stuff. Many thanks to Simon Alden for the sample and photographs. This story comes from the sea cliffs of Malta. Whilst I don’t have significant geochemical sampling for Malta, I have every reason to believe the Mediterranean location […]
Occasionally we see evidence for the diffusional path of hydrogen. Many thanks to Luis Fernandes Silva for the photos and sample. I was skimming through some photos that Luis sent me a few years ago when one in particular, from Sesimbra del Drento, caught my eye. This crag is a high-sulphate, sea cliff where the […]
The sulphate cliffs of Cabo da Roca demolish stainless steel. This fixed hanger is an exception. Many thanks to Luis Fernandes Silva for the sample. To date, the main thrust of this blog has been to attribute the extreme corrosivity of sulphate crags to the action of sulphate reducing bacteria (SRB). It has been observed […]
An example of an SS anchor chain exhibiting marked resistance to SRB attack Many thanks to Luis Fernandes Silva for the sample. On previous occasions I have reported on the sulphate-rich sea cliffs of Cabo da Roca. They are notorious for the aggressive corrosion of low grade austenitic stainless steels such as 304 (A2). Sulphate […]
Hydrogen Embrittlement THE FIFTH PART OF A MULTI-PART SERIES In conducting this work I have been greatly assisted by Luis Fernandes Silva and Rui Rosado who have provided multiple samples and photos for analysis. Luis has spent a great deal of time measuring spot-sulphate levels, and the pH profiles of the bolts that he has […]
We Find SRB Deep Inside the Bolt The fourth part of a multi-part series In conducting this work I have been greatly assisted by Luis Fernandes Silva and Rui Rosado who have provided multiple samples and photos for analysis. Luis has spent a great deal of time measuring spot-sulphate levels, and the pH profiles of […]
We Observe Brittle Fracture The third part of a multi-part series In conducting this work I have been greatly assisted by Luis Fernandes Silva and Rui Rosado who have provided multiple samples and photos for analysis. Luis has spent a great deal of time measuring spot-sulphate levels, and the pH profiles of bolts he has […]
This is so, even for a matching nut and bolt Thanks to Luis Fernandes Silva for providing the sample. It is not possible to talk sensibly of corrosion resistance without reference to the specific environment that is to be resisted.Whilst it is true we might not see performance differences between commercial samples of 304 SS […]
A tale of poor materials quality control. I needed a couple of samples of 304 for the development work I was doing, so I cut them from the threaded end of the bolt illustrated below. It’s nothing special, just a random sample from my large collection of old, glue-in, machine bolts extracted from crags around […]
The title should be fair warning. This one is going to get geeky. If an anchor component is at all attracted to a strong magnet, don’t install it at a crag with a reputation for eating hardware. If you asked your supplier for 316, yet find the product is attracted to a strong magnet, don’t […]