Laboratory Investigation of Environmentally Induced Cracking of API-X70 and X80 Pipeline Steels

2005 ◽  
Author(s):  
Kellen Rose de S. Lima ◽  
Ivani de S. Bott ◽  
Jose´ Antoˆnio da C. Ponciano Gomes
Keyword(s):  
Carbon Steels ◽  
Test Solution ◽  
Slow Strain Rate Test ◽  
Sodium Thiosulphate ◽  
Pipeline Steels ◽  
Experimental Procedure ◽  
Constant Loading ◽  
Test Pieces ◽  
Secondary Cracks ◽  
Rate Test

Carbon steels, used in pipelines for the transport of oil and its derivatives, are frequently exposed to fluids. This can result in stress induced corrosion cracking (SCC) and/or hydrogen embrittlement (HE). The present paper evaluates the susceptibility of pipeline steels (API-X70 and API-X80) to SCC and HE, using a slow strain rate test (SSRT) based on the National Association of Corrosion Engineers’ (NACE) norm and a traditional standard NACE test. The (SSRT) method used, employed a sodium thiosulphate solution to evaluate susceptibility to HE, thereby offering a simpler experimental procedure than the standard NACE test. The results confirm the efficacy of the sodium thiosulphate as an H2S–SCC susceptibility test solution when utilised in SSRT testing. Though no secondary cracks were detected in the materials investigated, both steels were observed to suffer a ductility loss upon exposure to this solution. In NACE type tests, the test pieces were subjected to constant loading at 80% of σy. Fracture did not occur for these samples.

Effects of water on the SCC of low carbon steel in ethanolic media

2015 ◽  
Vol 63 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Fortunate Moyo ◽  
Josias Willem Van der Merwe
Keyword(s):  
Carbon Steel ◽  
Design Methodology ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Slow Strain Rate Test ◽  
Low Carbon ◽  
Content Type ◽  
The World ◽  
Rate Test ◽  
Blended Fuels

Purpose – This paper aims to determine the effect of water on the SCC of low carbon steel in ethanol in the absence of supporting salts. Design/methodology/approach – Slow strain rate test was done to determine SCC susceptibility. Fractured samples were examined using optical microscopy and scanning electron microscopy. Findings – While the results demonstrated that water alone had no effect on the SCC susceptibility of low carbon steel in ethanol, 2.5 volume per cent moisture gave indications of cracking tendencies. Originality/value – With South Africa and the world over turning to bioethanol and ethanol blended fuels as a means of reducing its carbon foot print, there are concerns over the corrosive nature of ethanol on common engineering metals like low carbon steels.

Saw Welded Joints of Two API Steels Subject to SCC Laboratory Testing

2007 ◽  
Vol 539-543 ◽  
pp. 4440-4445 ◽  
Author(s):  
Franc A. Martins ◽  
J.A. Ponciano ◽  
Ivani de S. Bott
Keyword(s):  
Hydrogen Embrittlement ◽  
Welded Joints ◽  
Laboratory Testing ◽  
Laboratory Tests ◽  
Oil Industry ◽  
Slow Strain Rate Test ◽  
Sodium Thiosulphate ◽  
Steel Grades ◽  
Rate Test ◽  
Diffusion Of Hydrogen

Many steels tubes used in the Oil Industry are constantly exposed to hydrogen sulphide (H2S) which can lead to the diffusion of hydrogen into the steel, potentially provoking hydrogen embrittlement and/or stress corrosion cracking. Additionally the critical region in pipelines is usually considered to be the welded joints. In this work SAW welded joints of two API steels, grades X80 and X70, were evaluated using laboratory tests according to the NACE TM0177/96 METHOD A Standard and the slow strain rate test (SSRT) using a sodium thiosulphate solution. The results indicate that both steel grades can be susceptible to HE and SCC, since loss of ductility when submitted to SSRT and failure under NACE TM0177/96 METHOD A were observed.

scholarly journals Investigation of Stress Corrosion Cracking in Magnesium Alloys by Quantitative Fractography Methods

2017 ◽  
Vol 62 (2) ◽  
pp. 557-562 ◽  
Author(s):  
M. Sozańska ◽  
A. Mościcki ◽  
B. Chmiela
Keyword(s):  
Magnesium Alloy ◽  
Fracture Surface ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Quantitative Evaluation ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Rate Test ◽  
We43 Magnesium Alloy

Abstract The article shows that the use of quantitative fracture description may lead to significant progress in research on the phenomenon of stress corrosion cracking of the WE43 magnesium alloy. Tests were carried out on samples in air, and after hydrogenation in 0.1 M Na2SO4 with cathodic polarization. Fracture surfaces were analyzed after different variants of the Slow Strain Rate Test. It was demonstrated that the parameters for quantitative evaluation of fracture surface microcracks can be closely linked with the susceptibility of the WE43 magnesium alloy operating under complex state of the mechanical load in corrosive environments. The final result of the study was the determination of the quantitative relationship between Slow Strain Rate Test parameters, the mechanical properties, and the parameters of the quantitative evaluation of fracture surface (microcracks).

Stress Corrosion Cracking Behaviour of Flux Bounded TIG Welded AA2219 T87 Aluminum Alloy in 3.5 Weight Percent NaCl Solution

2015 ◽  
Vol 766-767 ◽  
pp. 733-738
Author(s):  
A.V. Santhana Babu ◽  
P.K. Giridharan ◽  
A. Venugopal ◽  
P. Ramesh Narayanan ◽  
S.V.S. Narayana Murty
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Weight Percent ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Nacl Solution ◽  
Test Technique ◽  
Rate Test

Limitation in penetration depth is a concern in conventional TIG welding. To improve penetration capability of TIG process, Flux Bounded TIG (FBTIG) has been developed. Stress corrosion cracking (SCC) behavior of FBTIG welds of aluminum alloy AA 2219 T87 is evaluated in 3.5 weight percent NaCl solution using Slow Strain Rate Test technique (SSRT) as per ASTM G129. SCC index defined as the ratio of the elongation of tensile tested specimen in NaCl to that of air is taken as a measure of the susceptibility to cracking. Based on the SCC index, it is concluded that the SCC resistance of FBTIG joints are good and comparable to that of conventional TIG welds.

scholarly journals Hydrogen Embrittlement Evaluation of Micro Alloyed Steels by Means of J-Integral Curve

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1843 ◽  
Author(s):  
Marina Cabrini ◽  
Ennio Sinigaglia ◽  
Carlo Spinelli ◽  
Marco Tarenzi ◽  
Cristian Testa ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Slow Strain Rate ◽  
Slow Strain Rate Test ◽  
Integral Parameter ◽  
Hydrogen Effect ◽  
J Integral ◽  
Pipeline Steels

The aim of this work is the evaluation of the hydrogen effect on the J-integral parameter. It is well-known that the micro alloyed steels are affected by Hydrogen Embrittlement phenomena only when they are subjected at the same time to plastic deformation and hydrogen evolution at their surface. Previous works have pointed out the absence of Hydrogen Embrittlement effects on pipeline steels cathodically protected under static load conditions. On the contrary, in slow strain rate tests it is possible to observe the effect of the imposed potential and the strain rate on the hydrogen embrittlement steel behavior only after the necking of the specimens. J vs. Δa curves were measured on different pipeline steels in air and in aerated NaCl 3.5 g/L solution at free corrosion potential or under cathodic polarization at −1.05 and −2 V vs. SCE. The area under the J vs. Δa curves and the maximum crack propagation rate were taken into account. These parameters were compared with the ratio between the reduction of area in environment and in air obtained by slow strain rate test in the same environmental conditions and used to rank the different steels.

Electrochemical Polarization and Stress Corrosion Cracking of Alloy 690 in 5-M Chloride Solutions at 25°C

CORROSION ◽  
2005 ◽  
Vol 61 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Y. Y. Chen ◽  
L. B. Chou ◽  
L. H. Wang ◽  
J. C. Oung ◽  
H. C. Shih
Keyword(s):  
Slow Strain Rate Test ◽  
General Corrosion ◽  
Side View ◽  
Nacl Solution ◽  
Passive Region ◽  
Ph Values ◽  
Alloy 690 ◽  
Rate Test ◽  
Nickel Based Alloy ◽  
Ph Range

Abstract An experimental, potential-pH diagram was constructed for the nickel-based Alloy 690 (UNS N06690) in 25°C concentrated (5 M) sodium chloride (NaCl) solution, using an electrochemical hysteresis method. The domains of immunity, general corrosion, passivation, and pitting in 5-M NaCl solutions were defined. At pH > 4, the passive region subdivided into areas of perfect passivation, imperfect passivation, and pitting. After anodic polarization, the surface of each specimen was carefully examined metallographically. Pitting corrosion was observed over the entire pH range investigated (0.3 to 8.52), but general corrosion predominated at lower pH values (<3). On the other hand, the mechanical properties, such as ultimate tensile strength (UTS), strain at fracture, and the reduction area (RA) measured by the slow strain rate test (SSRT), decreased significantly at pH < 3. The SSRT results are consistent with fractography and side-view observations of the tested specimens by scanning electron microscopy (SEM).

Hydrogen analysis and slow strain rate test in Ar gas for irradiated austenitic stainless steel

2001 ◽  
Vol 294 (3) ◽  
pp. 241-249 ◽  
Author(s):  
J Morisawa ◽  
M Kodama ◽  
N Yokota ◽  
K Nakata ◽  
K Fukuya ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Rate ◽  
Slow Strain Rate ◽  
Slow Strain Rate Test ◽  
Hydrogen Analysis ◽  
Rate Test ◽  
Ar Gas
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