Categories
Quick Note

Another SRB Resistant SS Anchor

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 […]

Categories
Short Report

Now This Is Different

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 […]

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Multi-Part Report

Corrosion at Cabo da Roca -5

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 […]

Categories
Multi-Part Report

Corrosion at Cabo da Roca – 4

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 […]

Categories
Multi-Part Report

Corrosion at Cabo da Roca – 3

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 […]

Categories
Short Report

Not all 304 SS is the same

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 […]

Categories
Quick Note

Nice Bar Stock – pay much for it?

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 […]

Categories
In Depth Investigation

Austenite stability – are we missing something here?

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 […]

Categories
Multi-Part Report

Corrosion at Cabo da Roca – 2

Sulphide Stress Cracking The second 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 extracted […]

Categories
Multi-Part Report

Corrosion at Cabo da Roca – 1

The story of a sulphate crag The first part of a multi-part 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 […]