Categories
Short Report

SSC vs SCC

Thanks to Luis Fernandes Silva for providing the sample. Which is it, sulphide stress cracking (SSC) or chloride-induced stress corrosion cracking (SCC)? I raised this question in one of my earlier posts where I described the aggressive corrosion of stainless steel at Cabo da Roca. In that particular post I highlighted the main differences between […]

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 (a)

The second of a four 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 during route refurbishment. […]

Categories
Multi-Part Report

Corrosion at Cabo da Roca – 1

The first of a four 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 during route refurbishment. […]

Categories
Quick Note

All parts made from 304 SS end up with the same corrosion resistance – right?

It’s not just the material you use, but critically, it matters how you use it. I have been researching the possibility that the brittle fractures we are seeing at Cabo da Roca and Sesimbra in Portugal are hydrogen embrittlement (HE) fractures mediated via the presence of sulphate reducing bacteria (SRB). Austenitic stainless steels like 304 […]

Categories
Quick Note

Never Say Never

The benign cliffs of Campo Escola da Barra da Lagoa I reported wall-wash results from this low-corrosion crag some time ago. The sulphate levels were not elevated, a fact which supports my mantra “no sulphate – no corrosion”. However, it always interesting to take a somewhat deeper look, which I was able to do thanks […]

Categories
Short Report

The Cliffs of Cabo da Roca

Home to some very corrosive sulphur crags. The Sintra volcanic complex, comprised mainly of granites and syenites, forms impressive, jagged sea cliffs that extend for several kilometres both north and south of the Cabo da Roca. Syenite is a low-silica form of granite, and looks very similar. Unlike typical granitic intrusions with their massive, sparsely-jointed […]

Categories
Quick Note

Laboratory Lock-down

This note was posted to the Titanium Bolting FB Group 1st April 2020 Being locked down is not so bad if you can keep working in your lab. I’ve finally caught up with some wall-wash samples sent to me by Rodrigo Castelan Carlson from the beautiful granite slab sea cliffs of Campo Escola da Barra […]

Categories
Quick Note

More Evidence for the Agency of SRB

This note was posted to the Titanium Bolting FB Group 10th March 2020 Warning: This gets a bit geekey, but I’ll simplify as much as possible. For the past few years I have concentrated on providing sufficient evidence for the theory that all marine crags showing SCC of 304SS are associated with high sulphate levels. […]

Categories
Quick Note

A Certain Ring of Truth

This note was posted to the Titanium Bolting FB Group 7 March 2020 Everyone knows and loves those huge lower-off rings we find at the top of climbs at Railay/Tonsai.However, some of us began to love them a whole lot less when it became clear that they too were subject to the dreaded SCC. If […]