Hydrogen cracking of high-strength steels during cathodic polarization in acid media

1974 ◽  
Vol 7 (6) ◽  
pp. 683-685
Author(s):  
F. F. Azhogin ◽  
E. V. Plaskeev ◽  
O. A. Gubenkova
Keyword(s):  
Cathodic Polarization ◽  
High Strength Steels ◽  
High Strength ◽  
Hydrogen Cracking ◽  
Acid Media

Weld Metal Hydrogen Cracking in Transmission Pipelines Construction

2010 ◽  
Author(s):  
Sheida Sarrafan ◽  
Farshid Malek Ghaini ◽  
Esmaeel Rahimi
Keyword(s):  
Weld Metal ◽  
Construction Projects ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Equivalent ◽  
Transverse Cracks ◽  
Diffusible Hydrogen ◽  
Hydrogen Cracking ◽  
Girth Welds ◽  
Welding Position

Developments of high strength steels for natural gas pipelines have been in the forefront of steelmaking and rolling technology in the past decades. However, parallel to such developments in steel industry, the welding technology especially with regards to SMAW process which is still widely used in many projects has not evolved accordingly. Decreasing carbon equivalent has shifted the tendency of hydrogen cracking from the HAZ to the weld metal. Hydrogen cracking due to its complex mechanism is affected by a range of interactive parameters. Experience and data gained from field welding of pipeline construction projects indicated that weld metal hydrogen cracking is related to welding position as it occurs more in the 6 o’clock position of pipeline girth welds. In this research an attempt is made to open up the above observation in order to investigate the contributory factors such as welding position and welding progression in terms of diffusible hydrogen and possibly residual stress considerations. It was observed that transverse cracks produced in laboratory condition may not be detected by radiography. But, the higher tendency for cracking at 6 o’clock position was confirmed through bend test. It is shown that more hydrogen can be absorbed by the weld metal in the overhead position. It is shown that welding progression may also have a significant effect on cracking susceptibility and it is proposed that to be due to the way that weld residual stresses are developed. The observations can have an important impact on planning for welding procedure approval regarding prevention of transverse cracking in pipeline girth welds.

Factors affecting hydrogen absorption of high-strength steels during cathodic polarization

1963 ◽  
Vol 3 (1) ◽  
pp. 17-33 ◽  
Author(s):  
K. Bolton ◽  
L.L. Shreir
Keyword(s):  
Hydrogen Absorption ◽  
Cathodic Polarization ◽  
High Strength Steels ◽  
High Strength ◽  
Factors Affecting

Determination of Critical Hydrogen Curves From Slow Bend Tests

2004 ◽  
Author(s):  
L. N. Pusseogda ◽  
A. Dinovitzer ◽  
D. Horsley
Keyword(s):  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Hydrogen Diffusivity ◽  
Hydrogen Cracking ◽  
Cold Temperatures ◽  
Steel Strength ◽  
Delayed Cracking ◽  
Two Parameters ◽  
Welding Procedure

Recent trends in the pipeline industry are towards the use of high strength steels. As steel strength increases, the delayed hydrogen cracking propensity in the welds also increases. As welding is often completed during winter months, the cold temperatures must be considered in determining joining procedures that will avoid delayed hydrogen cracking. The Graville/BMT Fleet Technology Limited hydrogen diffusion and cracking models have been used successfully in the past to predict delayed cracking and to demonstrate how changes implemented in the welding procedure can minimize the risk of cracking. The two capabilities, hydrogen diffusion and cracking assessment, can be applied to the case of X100 pipe as well, provided the hydrogen diffusivity and the hydrogen cracking susceptibility curves are established for the materials of interest. These two parameters, the hydrogen diffusivity and the hydrogen cracking susceptibility curves are developed to examine the hydrogen cracking susceptibility of SMAW and GMAW welds in X100 pipe, and are the focus of the paper.

Response of Short Cracks in High-Strength Steels to Fatigue Loadings—Part II: Behavior in Seawater Under Cathodic Polarization

1995 ◽  
Vol 117 (3) ◽  
pp. 192-199 ◽  
Author(s):  
K. Kim ◽  
W. H. Hartt
Keyword(s):  
Crack Growth ◽  
Cathodic Polarization ◽  
High Strength Steels ◽  
High Strength ◽  
Potential Drop ◽  
Offshore Structures ◽  
Natural Seawater ◽  
Short Cracks ◽  
Test Parameters ◽  
Point Bend

Experiments have been performed to determine the fatigue crack growth rate (FCGR) of short cracks (length from 0.1 to several mm) of five steels with yield stress in the range 370–570 MPa while cathodically polarized in natural seawater. Attention was focused on regions I and II of the classical FCGR-stress intensity range curve with particular consideration being given to the near-threshold behavior of short cracks. Single-edge notched, three-point bend specimens and a direct current potential drop crack monitoring system were employed; and test parameters were selected to simulate conditions experienced by deepwater offshore structures. These included a stress ratio of 0.5, a frequency of 0.3 Hz, and three levels of cathodic polarization (−800,−950, and −1100 mV, SCE). Crack growth rates were evaluated in terms of environment (air versus seawater), potential, material, and crack length. It was determined that cathodic polarization was generally beneficial with regard to FCGR compared to the freely corroding case, even at the most negative potential considered (−1100 mV, SCE), in contrast to what occurs for macro-cracks. The results are discussed within the context of design of offshore structures for resistance to fatigue.

Sign in / Sign up

Export Citation Format

Share Document