Some of many hundreds of miles of prestressed pipe installed in the late 1960’sand 1970’s have failed due to corrosion of the prestressing wire. Is it safe to follow conventional CP protection guidelines? Should the protection criteria be selected by age and condition of the pipeline, physical and mechanical properties of the wire, and the environmental conditions surrounding the pipeline?
Residual stresses are self-equilibrating stresses that exist in materials and structures at the absence of instantaneous application of external loadings. In industrial manufacturing and fabrication processes, such stresses can be prominent and may lead to premature failures if uncontrolled. Such failures can be manifested in many forms including stress corrosion cracking, fatigue cracking or brittle facture. This paper is devoted to providing a comprehensive review on residual stress in the manufacturing and fabrication domain with a greater emphasis on welding based residual stresses. Three residual stress evolution mechanisms will be evaluated covering deformation driven stresses during manufacturing, thermally driven during welding and surface modifications such as grinding, carburizing and plating. In welding processes, the residual stresses in the cooling cycle are characterized using Gleeble testing illustrating the stress profiles as a function of temperature. The effect of residual stresses in welded structures will be discussed covering fatigue performance, brittle fracture and effect on Stress Corrosion Cracking resistance. To ensure residual stresses are effectively measured and quantified, a total of nine (9) destructive, semi-destructive and non-destructive residual stress measurement techniques are evaluated. A comparison and evaluation of four (4) common residual stress mitigation techniques are also discussed covering Ultrasonic Impact Treatment, High Frequency Mechanical Impact, shot peening and Post-weld Heat Treatment. The review discussion extends to four (4) factors towards impacting the residual stress magnitude and distribution covering material properties, welding process and clamping and preheating during welding.
Material requirements for resistance to sulfide stress cracking (SSC) in sour refinery process environments (i.e., environments that contain wet hydrogen sulfide [H2S]). AKA "wet H2S cracking".
CORRECTION OF PUBLICATION:
In January 2016, NACE published an incorrect version of ANSI/NACE MR0103/ISO 17945:2015 (Petroleum, petrochemical and natural gas industries — Metallic materials resistant to sulfide stress cracking in corrosive petroleum refining environments). That document was incorrectly titled ANSI/NACE MR0103/ISO 17495:2016. The erroneous standard was retracted at the time and the NACE Store has the corrected version. NOTE: The contents of both versions of the standard are identical. The only discrepancies are in the title.