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

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 […]