Protect ya neck (aka Bad bolts in Sardinia)

Brian Sabourin wrote:SCC requires both corrosion and a sustained tensile stress. While the expansion bolts are in tension, a glue in bolt would not be. Wouldn't this suggest a different failure mechanism for the glue-ins?

Stainless glue-ins last longer than expansion bolts, but they still crack.

Brian's correct. The residual stresses in the metal, intentionally added to strengthen the steel, is enough for SCC to start. The same goes for hangers.

Search for "Low-Temperature Stress Corrosion Cracking of Stainless Steel in the Atmosphere in the Presence of Chloride Deposits" by Prosek, "Corrosion", February 2009, Vol 65, nos 2, page 105-117.

Standard U-bend samples of 304 and 316L stainless were exposed to CaCl2 and MgCl2 in controlled temp and relative humidity for a period of time. All samples cracked in ONLY 10 WEEKS when exposed to CaCl2 at 30C and 30%RH.

Limestone is essentially CaCO3, which disassociates in rainwater, producing Ca+ ions which combine with Cl- ions which are everywhere, but most abundant in marine environments. Limestone that is embedded with shells/fossils has its own Cl source.