Study of the Susceptibility of API 5L X80 Girth Welds to Sulfide Stress Corrosion Cracking and Hydrogen Embrittlement

2010 ◽  
Author(s):  
Adriana Forero Ballesteros ◽  
Jose´ A. da Cunha Ponciano ◽  
Ivani de S. Bott
Keyword(s):  
Hydrogen Embrittlement ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Oil And Gas ◽  
Hydrogen Permeation ◽  
Sodium Thiosulfate ◽  
Corrosion Cracking ◽  
Transmission Pipeline ◽  
Girth Welds ◽  
Almost All

The growing demand for natural gas and oil, as energy sources, has driven industry’s need for ever-increasing strength levels in oil and gas transmission pipeline materials in order to achieve safe and economic transportation. The current world trend points to the use of pipes with larger diameters and thinner wall thicknesses, operating under high pressure. In addition, pipeline steels for sour service must exhibit good Hydrogen Induced Cracking (HIC) and Sulphide Stress Corrosion Cracking (SSCC) resistance. This study evaluates the susceptibility of API 5L-X80 girth welds to SSCC and Hydrogen Embrittlement (HE). Slow strain rate tensile (SSRT) tests and Hydrogen Permeation tests were performed at room temperature, in different acidic environment containing sodium thiosulfate solutions. Most of the SSRT tests undertaken in solution, showed a loss of ductility and a decrease in the reduction of area, as compared with tests conducted in air. The susceptibility to HE and potentially SSCC was evidenced by a reduction in ductility in the SSRT tests and an increase in the hydrogen permeation current values, for almost all welded joints. This was observed with greater intensity for the more acidic test solutions (pH = 3.4), while for the less acidic test solutions (pH = 4.4) little loss of ductility was observed and the hydrogen permeation current remained at values close to zero, indicating little or no permeation of hydrogen through the metal for the testing times applied. The behaviour exhibited by the samples tested in the more acidic solutions was attributed to the dissolution of material from the sample together with hydrogen embrittlement. These results confirmed that the use of sodium thiosulfate solutions to generate H2S, permits the study of phenomena related to SCC in environments containing sulphides.

Evaluation of Stress Corrosion Cracking, Sulfide Stress Cracking, Galvanic-Induced Hydrogen Stress Cracking, and Hydrogen Embrittlement Resistance of Aged UNS N06625 Forged Bars

CORROSION ◽  
10.5006/3590 ◽  
2020 ◽  
Vol 76 (12) ◽  
pp. 1207-1219
Author(s):  
A. Febbrari ◽  
R. Montani ◽  
C. Veronesi ◽  
M. Cavagnola ◽  
E. Brognoli ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Oil And Gas ◽  
Corrosion Cracking ◽  
Aged Alloy ◽  
Second Phase ◽  
Stress Cracking ◽  
Sulfide Stress ◽  
Sulfide Stress Cracking

UNS N06625 is a nickel-based superalloy used for oil and gas applications and commonly produced according to NACE MR0175 in the annealed/solution annealed condition. The annealing/solution annealing treatment makes the material corrosion resistant in the most challenging environments, in the presence of sulfides and chlorides at high pressure and temperature. However, thanks to its chemical composition, UNS N06625 can also be considered as an age-hardenable material whose mechanical strength can be improved by promoting the metastable second phase γ′′ precipitation into the γ matrix. However, the corrosion behavior of the aged alloy has never been investigated in NACE environments. This paper aims to understand the suitability of the age-hardened condition of UNS N06625 for oil and gas applications through the evaluation of the material corrosion performance in NACE level VII environments by using NACE TM0177 tests. Three heats of UNS N06625 have been produced and forged in different bar diameters: 152 mm (6 in), 203.2 mm (8 in), and 254 mm (10 in). Afterward, the bars have been annealed and age-hardened according to optimized time-temperature parameters and finally tested to assess their mechanical properties and resistance to stress corrosion cracking, sulfide stress cracking, galvanic-induced hydrogen stress cracking, and hydrogen embrittlement.

scholarly journals Stress Corrosion Cracking of Additively Manufactured Alloy 625

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6115
Author(s):  
Marina Cabrini ◽  
Sergio Lorenzi ◽  
Cristian Testa ◽  
Francesco Carugo ◽  
Tommaso Pastore ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Strain ◽  
Corrosion Cracking ◽  
Slow Strain Rate ◽  
Laser Source ◽  
Alloy 625

Laser bed powder fusion (LPBF) is an additive manufacturing technology for the fabrication of semi-finished components directly from computer-aided design modelling, through melting and consolidation, layer upon layer, of a metallic powder, with a laser source. This manufacturing technique is particularly indicated for poor machinable alloys, such as Alloy 625. However, the unique microstructure generated could modify the resistance of the alloy to environment assisted cracking. The aim of this work was to analyze the stress corrosion cracking (SCC) and hydrogen embrittlement resistance behavior of Alloy 625 obtained by LPBF, both in as-built condition and after a standard heat treatment (grade 1). U-bend testing performed in boiling magnesium chloride at 155 and 170 °C confirmed the immunity of the alloy to SCC. However, slow strain rate tests in simulated ocean water on cathodically polarized specimens highlighted the possibility of the occurrence of hydrogen embrittlement in a specific range of strain rate and cathodic polarization. The very fine grain size and dislocation density of the thermally untreated specimens appeared to increase the hydrogen diffusion and embrittlement effect on pre-charged specimens that were deformed at the high strain rate. Conversely, heat treatment appeared to mitigate hydrogen embrittlement at high strain rates, however at the slow strain rate all the specimens showed a similar behavior.

scholarly journals Hydrogen effects in non-ferrous alloys: discussion

2017 ◽  
Vol 375 (2098) ◽  
pp. 20170030 ◽  
Author(s):  
Mitesh Patel ◽  
Miles A. Stopher
Keyword(s):  
Hydrogen Embrittlement ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Discussion Session ◽  
Ferrous Alloys ◽  
Delayed Hydride Cracking ◽  
Hydride Cracking

This is a transcript of the discussion session on the effects of hydrogen in the non-ferrous alloys of zirconium and titanium, which are anisotropic hydride-forming metals. The four talks focus on the hydrogen embrittlement mechanisms that affect zirconium and titanium components, which are respectively used in the nuclear and aerospace industries. Two specific mechanisms are delayed hydride cracking and stress corrosion cracking. This article is part of the themed issue ‘The challenges of hydrogen and metals’.

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