time and again, we find that the nickel content of failed 316 is below specification, until… Thanks to Josh Lyons of the Thaitanium Project for the heap of corroded hardware pulled from the walls of Railay/Tonsai. Without such real world samples, all is mere speculation. We find a broken bolt from Railay/Tonsai which is absolutely […]
Tag: martensite
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Thailand Crags – 2
Sulphide Stress Cracking (SSC) The second part of a multi-part series For SCC see Part 1 Tonsai/Railay is where stainless-steel anchors go to die. We can now add, that the cause is SRB-mediated SSC. Introduction: I owe much to Martin Roberts of Titan Climbing for taking the initial steps of our great adventure into crag chemistry. […]
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Is this a 316 failure?
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 […]
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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 […]
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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 […]
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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 […]
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 […]
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 […]