Hydrogen-Induced Cracking Caused by Galvanic Corrosion of Steel Weld in a Sour Environment

Abstract

This study examined the hydrogen-induced cracking (HIC) caused by galvanic corrosion of an ASTM A516-65 steel weld in a wet sour environment using a combination of standard immersion corrosion test, electrochemical analyses, and morphological observation of corrosion damage. This study showed that the weld metal has lower open circuit potential, and higher anodic and cathodic reaction rates than the base metal. The preferential dissolution and much higher density of localized corrosion damage were observed in the weld metal of the welded steel. On the other hand, the presence of weldment can make steel more susceptible to HIC, specifically, in areas of the base metal but not in the weld metal or heat affected zone, which is in contrast to typical expectations based on metallurgical knowledge. This can be explained by galvanic corrosion interactions between the weldment and the base metal, acting as a small anode and a large cathode, respectively. This type of galvanic couple can provide large surface areas for infusing cathodically-reduced hydrogen on the base metal in wet sour environments, increasing the susceptibility of welded steel to HIC.

Localized Depth of Galvanic Corrosion at Dissimilar Metal Welding A508/Inconel 182/316L

“…Previous studies (Okonkwo et al, 2019) found that in the welded parts of A508 and other series stainless steel areas, the fine-grained region of low-alloy steel near the fusion boundary is the most prone to galvanic corrosion. However, the crack produced by galvanic corrosion may induce crevice corrosion, which intensifies the corrosion of welded parts (Park et al, 2021).…”

Special Issue: Corrosion Properties and Mechanism of Steels

“…The article reports the results of the examination of the protective properties of silane coatings based on vinyltrimethoxysilane and ethanol, doped with the following electrolytes: acetic acid, lithium perchlorate LiClO 4 , sulphuric acid H 2 SO 4 and ammonia NH 3 . Park et al [ 10 ] examined the hydrogen-induced cracking caused by galvanic corrosion of an ASTM A516-65 steel weld in a wet sour environment using a combination of a standard immersion corrosion test, electrochemical analyses and morphological observation of the corrosion damage. Wang et al [ 11 ] investigated the effects of Ti and Cu addition on inclusion modification and corrosion behavior in the simulated coarse-grained heat-affected zone of low-alloy steels by using an in situ scanning vibration electrode technique, a scanning electron microscope/energy-dispersive X-ray spectroscopy and an electrochemical workstation.…”