Performance of High Strength UNS N08830 in Hydrogen Stress Crack Testing to Simulate Conditions Arising from Subsea Cathodic Protection

摘要

The study of hydrogen stress cracking of various Nickel based alloys has recently been reported by others and is a subject of increasing interest. This paper describes results for different test methods, including Slow Strain Rate Testing (SSRT), Incremental Step Loading (ISL), and Constant Load Verification (CLV). A new Ni-Cr-Mo-Fe alloy UNS N08830 alloy was recently evaluated for resistance to Hydrogen Induced Stress Cracking (HISC), simulating conditions arising during cathodic protection in a subsea environment. The unique set of test methods and conditions included SSRT and ISL, all using pre-charged specimens with ongoing continuous charging during testing. Test specimens utilized different geometries, including smoothed and notched, along with round and rectangular cross sections. The paper draws key conclusions based on comparisons of test methods, and also compares UNS N08830 alloy results to other high strength CRA's used in Oil and Gas subsea production equipment.