Hydrogen stress cracking resistance and hydrogen transport properties of ASTM A508 grade 4N

CORROSION ◽  
10.5006/3949 ◽  
2021 ◽  
Author(s):  
Esteban Rodoni ◽  
Andreas Viereckl ◽  
Zakaria Quadir ◽  
Aaron Dodd ◽  
Kim Verbeken ◽  
...  

Low alloy steels combine relatively low cost with exceptional mechanical properties, making them commonplace in oil and gas equipment. However, their strength and hardness are restricted for sour environments to prevent different forms of hydrogen embrittlement. Materials used in sour services are regulated by the ISO 15156-2 standard, which imposes a maximum hardness of 250 HV (22 HRC) and allows up to 1.0 wt% Ni additions due to hydrogen embrittlement concerns. Low alloy steels that exceed the ISO 15156-2 limit have to be qualified for service, lowering their commercial appeal. As a result, high-performing, usually high-nickel, low alloy steels used successfully in other industries are rarely considered for sour service. In this work, the hydrogen stress cracking resistance of the high-nickel (3.41 wt%), quenched and tempered, nuclear-grade ASTM A508 Gr.4N low alloy steel was investigated using slow strain rate testing as a function of applied cathodic potential. Results showed that the yield strength and ultimate tensile strength were unaffected by hydrogen, even at a high negative potential of -2.00 V<sub>Ag/AgCl</sub>. Hydrogen embrittlement 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 hydrogen at high cathodic potentials than a low-strength (yield strength = 340 MPa) ferritic-pearlitic low alloy steel of similar nickel content. Additionally, hydrogen diffusivity was measured using the hydrogen permeation test. The calculated hydrogen diffusion coefficient of the ASTM A508 Gr.4N was two orders of magnitude smaller when compared to that of ferritic-pearlitic steels. Hydrogen embrittlement and diffusion results were linked to the microstructure features. The microstructure consisted in a bainitic/martensitic matrix with the presence of Cr<sub>23</sub>C<sub>6</sub> carbides as well as Mo and V-rich precipitates, which might have played a role in retarding hydrogen diffusion, kept responsible for the improved HE resistance.

Author(s):  
Steven L. McCracken ◽  
Richard E. Smith

Temperbead welding is common practice in the nuclear power industry for in-situ repair of quenched and tempered low alloy steels where post weld heat treatment is impractical. The temperbead process controls the heat input such that the weld heat-affected-zone (HAZ) in the low alloy steel is tempered by the welding heat of subsequent layers. This tempering eliminates the need for post weld heat treatment (PWHT). Unfortunately, repair organizations in the nuclear power industry are experiencing difficulty when attempting to qualify temperbead welding procedures on new quenched and tempered low alloy steel base materials manufactured to modern melting and deoxidation practices. The current ASME Code methodology and protocol for verification of adequate fracture toughness in materials was developed in the early 1970s. This paper reviews typical temperbead qualification results for vintage heats of quenched and tempered low alloy steels and compares them to similar test results obtained with modern materials of the same specification exhibiting superior fracture toughness.


CORROSION ◽  
10.5006/2724 ◽  
2018 ◽  
Vol 74 (7) ◽  
pp. 801-818
Author(s):  
Hans Husby ◽  
Philip Wagstaff ◽  
Mariano Iannuzzi ◽  
Roy Johnsen ◽  
Mariano Kappes

Nickel additions to low alloy steels improve mechanical and technological properties. However, Part 2 of ISO Standard 15156 limits the nickel content to a maximum of 1 wt% in oil and gas environments containing H2S because of controversial concerns regarding sulfide stress cracking. The objective of this work was to investigate the effect of nickel in solid solution in the ferrite phase on hydrogen stress cracking resistance. Ferritic/pearlitic research-grade low alloy steels with nominal nickel contents of 0, 1, 2, and 3 wt% were tested by the slow strain rate test method with cathodic hydrogen charging to −1.05 VAg/AgCl and −2 VAg/AgCl. No difference in fracture mode or morphology was found between the alloys. However, the plastic elongation ratios and reduction in area ratios decreased with increasing nickel content when tested at −2 VAg/AgCl. The direct and indirect effects of nickel, such as the influence of an increasing fraction of pearlite with increasing nickel content, are discussed.


CORROSION ◽  
1982 ◽  
Vol 38 (9) ◽  
pp. 457-463 ◽  
Author(s):  
Bruce D. Craig

Abstract Literature is reviewed on the effect of nickel in low alloy steels on their resistance to hydrogen stress cracking. The greatest portion of literature pertains to H2S environments since there is a controversy in the petroleum industry as to the effect of Ni. Addition of greater than 1 % Ni to carbon and low alloy steels is considered to be either detrimental or of no effect in an alloy's resistance to hydrogen stress cracking. This review should provide a starting point from which more organized studies can be performed to evaluate the true effect of Ni on hydrogen cracking resistance.


2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Harsisto .

Research-based characterization of low alloy steel chrome andmanganese is done because of the problem of corrosion and corrosion limit water evenly on low carbon steel. Based on the findings, the engine coolant is switched on-and off every day so there was influence of outside air and the decrease of the temperature to room temperature. Based on the research and discussion of the characteristics of the five types low alloy steel containing 0.5 wt% manganese in the medium 60% LiBr + 0.2% LiOH at a temperature of (150 ± 2) ° C and exposure to atmospheric air for 50 hours and 110 hours , it showed that the corrosion rate is dependent on the level of content of the chromium. In the addition of the chromium in low alloy steels exposed in the test solution, there is no consistency in the natural corrosion potential value, but in general all test objects were in a corroded state.Keywords : air conditioner, low alloy steel, corrosion, LiBr, LiOH, the boiling temperature and the room temperature.AbstrakPenelitian karakterisasi baja paduan rendah berbasis krom dan mangan ini dilakukan karena adanya masalah korosi merata dan korosi batas air pada baja karbon rendah. Berdasar fakta di lapangan,mesin pendingin tersebut dilakukan “on-Off” setiap hari sehingga ada pengaruh udara luar dan turunnya suhu hingga suhu ruangan. Berdasarkan penelitian dan pembahasan tentang karakteristik 5 jenis baja paduan rendah dengan kandungan 0,5% berat unsur mangan dalam media 60% LiBr + 0,2% LiOH pada suhu(150±2) °C dan ekspos udara atmosfer selama 50 jam dan 110 jam, hasilnya menunjukkan bahwa laju korosi masih tergantung pada kadar kandungan unsur krom. Pada penambahan unsur krom dalam baja paduan rendah yang diekspos dalam larutan uji, tidak menunjukkan adanya konsistensi harga potensial korosi alaminya, tetapi secara umum semua benda uji berada dalam keadaanterkorosi.Kata Kunci : mesin pendingin ruangan, baja paduan rendah, korosi, LiBr,LiOH, suhu didih dan suhu ruangan.AbstrakPenelitian karakterisasi baja paduan rendah berbasis krom dan mangan inidilakukan karena adanya masalah korosi merata dan korosi batas air padabaja karbon rendah.Berdasar fakta di lapangan,mesin pendingin tersebut dilakukan “on-Off” setiaphari sehingga ada pengaruh udara luar dan turunnya suhu hingga suhuruangan. Berdasarkan penelitian dan pembahasan tentang karakteristik 5jenis baja paduan rendah dengan kandungan 0,5% berat unsur mangandalam media 60% LiBr + 0,2% LiOH pada suhu(150±2) °C dan ekspos udaraatmosfer selama 50 jam dan 110 jam, hasilnya menunjukkan bahwa lajukorosi masih tergantung pada kadar kandungan unsur krom. Padapenambahan unsur krom dalam baja paduan rendah yang diekspos dalamlarutan uji, tidak menunjukkan adanya konsistensi harga potensial korosialaminya, tetapi secara umum semua benda uji berada dalam keadaanterkorosi.Kata Kunci : mesin pendingin ruangan, baja paduan rendah, korosi, LiBr,LiOH, suhu didih dan suhu ruangan.


1988 ◽  
Vol 19 (9) ◽  
pp. 2171-2177 ◽  
Author(s):  
Hitoshi Asahi ◽  
Yasuo Sogo ◽  
Masakatsu Ueno ◽  
Hirokichi Higashiyama

Author(s):  
Yu.S. Slupska ◽  
L.M. Dadiverina ◽  
D.Yu. Chashyn ◽  
H.O. Toropchenov ◽  
M.O. Pyko

Problem statement. Most modern materials have a polycrystalline structure. Their most important property − mechanical strength − is determined by the defective structure of the crystals. Under the defective structure should be understood not only the concentration and distribution of point defects, dislocations, packaging defects, but also the grain boundaries. The development of such processes as diffusion, recrystallization, plasticity, creep, fragility, cracking and corrosion resistance depends on the grain boundaries. The degree of this influence is directly related to the peculiarities of the atomic structure of boundaries and their interaction with other defects. Therefore, the study of the influence of interfacial and intraphase boundaries on the development of plastic deformation in modern materials is an urgent task. Purpose of the article. Investigation of the influence of the type of polycrystalline boundaries on the kinetics of propagation of plastic deformation in low-carbon low-alloy steel 06Х1. Conclusion. Investigation of the influence of the type of polycrystalline boundaries on the kinetics of propagation of plastic deformation in low-carbon low-alloy steel 06Х1. Conclusion. For low-carbon low-alloy steel 06Х1 the influence of the type of polycrystalline boundaries on the kinetics of plastic deformation propagation is investigated. The relationship between the propagation of plastic deformation and the type of interfacial and intraphase boundaries is established. The proposed physical model takes into account the ability of structural components to block plastic deformation. Keywords: propagation of plastic deformation; boundaries of a special type; boundaries of a general type


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