Search
Filters
Close

Celebrate World Corrosion Awareness Day with 20% off eCourses and eBooks with code WCAD2024 at checkout!

An Exploratory Investigation of the Cracking Susceptibility of Three Corrosion Resistant Alloys under Thermal Cycles and Conditions Exceeding the Traditional NACE MR0175/ISO 15156 Recommendations

The environmentally-assisted cracking (EAC) of three wrought corrosion-resistant alloys (CRAs) with a minimum yield strength of 110ksi (760MPa) was investigated between 70°F (21°C) and 450°F (232°C) through weekly thermal cycles totalizing 42 days. The thermal cycling was introduced to approximate service equipment conditions and gain additional confidence on the EAC-free limits of all three CRAs. Alloys 17-4PH, K-500, and 925 were selected and exposed to a 180,000-ppm NaCl brine (pH=2.75) in equilibrium with 1000 psi (68.95 bar) H2S, 1000 psi (68.95 bar) CO2, and 2500 psi (172.37 bar) CH4. All three CRAs were (a) acquired as per the NACE MR0175/ISO 1516 requirements (1), (b) tested as per NACE TM0177 Method C at 30-to-90% of the CRA minimum specified minimum yield strength (SMYS), and (c) also compared for their weight-loss corrosion and localized corrosion. The results show: (a) Alloy 17-4PH remains resistant to EAC below 45% of its SMYS, (b) Alloy K-500 resists cracking at an estimated 80% of its SMYS, but uniformly corrodes by sulfide conversion under film at a rate of 64 mpy (1.63 mm/yr.), and (c) Alloy 925 continues to be immune to EAC at 90% of its SMYS. Alloy 17-4PH also corroded at a rate of 22.8 mpy (0.58 mm/yr.) in comparison to only 0.6 mpy (15.2 mm/yr.) for Alloy 925, with no CRA showing experiencing crevice corrosion.
Product Number: 51324-20455-SG
Author: Manuel Marya
Publication Date: 2024
$40.00
$40.00
$40.00