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Picture for The Effect of Hydrogen on Plain and Notched Test Specimens of PH Nickel Alloys
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51317--9655-The Effect of Hydrogen on Plain and Notched Test Specimens of PH Nickel Alloys

Product Number: 51317--9655-SG
ISBN: 9655 2017 CP
Author: Stephen McCoy
Publication Date: 2017
$20.00

This paper reviews previous work and shows laboratory results using different test techniques to demonstrate the influence of yield strength and microstructure on the resistance to Hydrogen Stress Cracking of precipitation hardenable Nickel alloys N07718, N09925, N07725, N09945 and N09946.

Picture for Comparison Of Hydrogen Embrittlement Testing Methods Of Alloy 718
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Comparison Of Hydrogen Embrittlement Testing Methods Of Alloy 718

Product Number: 51321-16821-SG
Author: Brian Kagay; Stevew Coryell; Kip Findlet; Steve McCoy
Publication Date: 2021
$20.00
Picture for High-strength Nickel Low Alloy Steels for Oil and Gas Equipment: ASTM A508 Grade 4N under cathodic protection and simulated sour environments.
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High-strength Nickel Low Alloy Steels for Oil and Gas Equipment: ASTM A508 Grade 4N under cathodic protection and simulated sour environments.

Product Number: 51320-14706-SG
Author: Andreas Viereckl, Esteban Rodoni, Zakaria Quadir, Garry Leadbeater and Mariano Iannuzzi, Yuta Honma
Publication Date: 2020
$20.00

Low alloy steels (LASs) combine relatively low cost with exceptional mechanical properties, making LASs commonplace in Oil and Gas equipment. However, the strength and hardness of LASs for sour environments and for applications that generate atomic hydrogen at the surface, e.g., cathodic protection, is limited to prevent different forms of hydrogen embrittlement (HE) such as hydrogen stress cracking (HSC) and sulfide stress cracking (SSC). As a result, the specified minimum yield strength (SMYS) of forged LASs for, e.g., subsea components, rarely exceeds 550 MPa (80 ksi), while the most common pipeline steels are API(1) X65 to X70, with a SMYS of 450 MPa (65 ksi) and 482 MPa (70 ksi), respectively. Moreover, ISO(2) 15156-2 restricts LASs to a maximum of 1.0 wt% Ni due to SSC concerns. The LASs that exceed the ISO 15156-2 limit have to be qualified for service, lowering their commercial appeal.  

In this work, the HSC resistance of the high-nickel (3.41 wt%), quenched and tempered (Q&T), nuclear-grade ASTM(3) A508 Gr.4N LAS was investigated using slow strain rate testing (SSRT) as a function of applied cathodic potential. Results showed that the yield strength (YS) and ultimate tensile strength (UTS) were unaffected by hydrogen, even at a high negative potential of -2.0 VAg/AgCl. HE effects were observed once the material started necking, manifested by a loss in ductility with increasing applied cathodic potentials. Indeed, A508 Gr.4N was less affected by H at high cathodic potentials than a low-strength (YS = 340 MPa) ferritic-pearlitic LAS of similar nickel content. SSRT results were linked to microstructure features, which were characterized by light optical microscopy (LOM), scanning electron microscopy (SEM) coupled to electron backscatter diffraction (EBSD). 

Picture for Hydrogen Stress Cracking Resistance of Precipitation Hardenable Nickel Alloys and Optimization
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Hydrogen Stress Cracking Resistance of Precipitation Hardenable Nickel Alloys and Optimization

Product Number: 51324-20719-SG
Author: Stephen McCoy; Brian A. Baker; William MacDonald
Publication Date: 2024
$40.00
The material trend in the Oil & Gas sector is for high strength materials with high levels of corrosion resistance to resist increasingly harsh sour downhole environments. Compared to sweet wells the presence of hydrogen sulphide, elemental sulphur and hydrogen generally requires material selection of tubular and bar products in high performance stainless steels and nickel base alloys to withstand the pressures and temperatures. The materials of choice must be corrosion resistant, cost effective, reliable and have the strength required for the well design conditions. The material selection for downhole and well head equipment such as hangers, sub-surface safety valves, pumps and packers require age-hardenable materials to obtain the strength in heavier cross sections which cannot be strengthened by cold work. The commonly used nickel alloys for the sour service applications are alloy UNS N09925 (925), alloy UNS N07718 (718) and alloy UNS N07725 (725) with the more recently developed alloy UNS N09945 (945) and alloy UNS N09946 (945X) designed for HP/HT and sour wells. The metallurgical stability and freedom from detrimental phases of these materials being increasingly important to optimise the mechanical and corrosion resistant properties, particularly as larger section thicknesses of higher strength materials. The effect of the microstructure of these materials is shown to have a significant effect on the resistance to hydrogen attack and corrosion in sour environments. Optimising the compositional control, thermomechanical processing and microstructure is shown to give significant improvements in resistance to sour corrosion and hydrogen stress cracking resistance of materials used for critical downhole components. Over recent years there has been increasing industry demand to improve quality control and categorise the various PH Nickel alloy grades resistance to Hydrogen Stress Cracking (HSC) for critical High Pressure-High Temperature environments. HSC is a complex corrosion mechanism with many factors including composition, strength, microstructure, and grain boundary cleanliness influencing susceptibility. Evaluation efforts have used multiple techniques to measure the effects of HSC resistance, with this paper focusing on the Slow Strain Rate Test (SSRT) method according to TM0198 Method C(1) and using the quality control standard API*6ACRA(2). The purpose of the paper is to present results using the TM0198:C slow strain rate test method in a hydrogen charging environment and show the HSC resistance of the grades 925, 718, 945, 945X, and 725. This paper shows how the composition can be controlled within the defined limits of the alloy grade to optimise the HSC resistance by reducing precipitation of deleterious phases and reduce mill heat batch variation. The SSRT results are compared with mechanical properties determined according to API6ACRA(2) and detailed microstructural analysis.
Picture for The Effect Of Interactions Between Cathodic Protection Potential And Stress Concentration On Hydrogen Embrittlement Of Precipitation-Hardened Nickel Alloys
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The Effect Of Interactions Between Cathodic Protection Potential And Stress Concentration On Hydrogen Embrittlement Of Precipitation-Hardened Nickel Alloys

Product Number: 51321-16663-SG
Author: Imran Bhamji; Kasra Sotoudeh; Menno Hoekstra; Herman Amaya; Bryan Fahimi
Publication Date: 2021
$20.00