Fatigue-Corrosion of High Strength Steels in Synthetic Seawater under Cathodic Protection

2020 ◽  
Vol 841 ◽  
pp. 294-299
Author(s):  
Sergio Lorenzi ◽  
Cristian Testa ◽  
Marina Cabrini ◽  
Francesco Carugo ◽  
Luigi Coppola ◽  
...  
Keyword(s):  
Cathodic Protection ◽  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Loading Frequency ◽  
Offshore Pipelines ◽  
Synthetic Seawater ◽  
Steel Grades ◽  
Protection Potential ◽  
Fatigue Corrosion

The paper is aimed to the study of the corrosion-fatigue behavior of high strength steels for offshore pipelines. Tests have been performed in order to study fatigue crack growth in synthetic seawater under cathodic protection. The tests have been carried out on three different steel grades from 65 to 85 ksi with tempered martensite and ferrite-bainite microstructures. The effect of stress intensity factor, cathodic protection potential and cyclic loading frequency is shown.

Corrosion-Fatigue Performance of High-Strength Riser Steels in Seawater and Sour Brine Environments

2011 ◽  
Author(s):  
Stephen J. Hudak ◽  
Guadalupe B. Robledo ◽  
Jeffrey Hawk
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Cathodic Protection ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Performance ◽  
Material Strength ◽  
Loading Frequency

Although new high-strength steels have recently been developed to meet the demands of increased reservoir pressures, and sour production fluids, the corrosion-fatigue performance of these new higher-strength materials is largely unknown. The goal of this study was to fill this knowledge gap by generating corrosion-fatigue data in two aggressive environments: 1) a sour production brine, and 2) seawater with cathodic protection. The focus of the current paper is on stress-life (S-N) corrosion-fatigue results in these environments, as well as a baseline air environment. Experiments were performed on five different steels with yield strengths ranging from 848 MPa to 1080 MPa. Prior frequency-scan results based on corrosion-fatigue crack growth rate data demonstrated that not all of these material-environment combinations exhibit a saturation frequency where the detrimental environmental effect approached a constant value as the cyclic loading frequency is decreased. Consequently, S-N tests were performed at different frequencies (0.01 Hz, 0.17 Hz, and 1 Hz), depending on the fatigue life regime, in attempting to match the loading frequencies experienced in service. Corrosion-fatigue occurred at stresses well below the fatigue endurance limit in laboratory air, and cyclic lives in the seawater with cathodic protection environment were found to be 2X to 10X less than those in the baseline air environment, while cyclic lives in the sour brine environment were found to be 30X to 100X less than those in the baseline air environment. In both environments, degradation was greatest at lower stresses in the high cycle fatigue regime. The effect of material strength level had little or no measurable effect on the S-N corrosion-fatigue performance, and the effect of cyclic frequency on the corrosion-fatigue performance was mixed. The S-N response to these two variables differed significantly from recently measured fatigue crack growth kinetics in these same materials that were performed in a companion study. Possible reasons for these differences are discussed.

scholarly journals Fatigue characteristics of welded high strength steel in the low cycle region of loading

2019 ◽  
Vol 254 ◽  
pp. 07002
Author(s):  
Peter Kopas ◽  
Milan Sága ◽  
Marián Handrik ◽  
Milan Vaško ◽  
Lenka Jakubovičová
Keyword(s):  
Low Frequency ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Loading Frequency ◽  
Fuel Savings ◽  
Fatigue Characteristics ◽  
Structural Parts ◽  
The One ◽  
Metal Welding

Automotive industry is the one of the most rapidly developing sector of engineering. Using of new, progressive materials can make significant benefits because of growing durability and reducing weight of structural parts, which can lead to the materials and fuel savings. The authors of this paper discuss fatigue characteristics on arc metal welding process of high strength steels STRENX 700MC obtained in low cycle region (N approximate to 1.10(3) divided byN= 1.10(7) cycles) at low-frequency loading (frequency approximate to 35 Hz, T = 20 +/5 degrees C,R= -1). Authors compares results of their own experimental works and subsequently discus these result and their possible effect on the fatigue lifetime of these steels.

Structural Performance Evaluation of Built-Up Stub Steel Column with Various Steel Grades under Concentric Loading

2015 ◽  
Vol 764-765 ◽  
pp. 127-131
Author(s):  
Yang Yang ◽  
Kang Min Lee ◽  
Keun Yeong Oh ◽  
Sung Bin Hong
Keyword(s):  
Tensile Strength ◽  
High Strength Steel ◽  
Local Stability ◽  
Experimental Studies ◽  
High Strength Steels ◽  
High Strength ◽  
Design Criteria ◽  
Stability Criteria ◽  
Steel Grades ◽  
Concentric Loading

The current local stability criteria (KBC2009, AISC2010) are enacted through theoretical and experimental studies of ordinary steels, but the mechanical properties of high strength steels are different from ordinary steels. The high strength steel in the applicability of design criteria should be needed to review because of increasing market demanding for high strength steel in the high-rise and long span buildings. In this study, stub columns of H-shaped and box section with various steel grades subjected to concentric loading were investigated, and these steels were checked to the applicability of current local stability criteria. The difference between the ordinary steel and high strength steel was compared. As a result of comparison with various steel grades, most specimens were satisfied with the design criteria, but some specimens with lower tensile strength were not reached the required strength. It is considered that the uncertainty of material was the higher when the tensile strength of material was the lower.

Study of Fatigue Behavior for Spot Welded Tensile Shear Specimens of Advanced High Strength Steels

2012 ◽  
Vol 83 (10) ◽  
pp. 988-994 ◽  
Author(s):  
Gert Weber ◽  
Stephan Brauser ◽  
Holger Gaul ◽  
Michael Rethmeier
Keyword(s):  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Shear ◽  
Advanced High Strength Steels ◽  
Spot Welded

313 Effect of Stress Ratio on Long-Life Fatigue Behavior in High Strength Steels

2005 ◽  
Vol 2005 (0) ◽  
pp. 197-198
Author(s):  
Kazuaki SHIOZAWA ◽  
Seiichi NISHINO ◽  
Takayuki HASEGAWA ◽  
Yasuyuki YACHI
Keyword(s):  
Stress Ratio ◽  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Long Life

Fatigue Assessment of Tubular Automotive Components in Presence of Inhomogeneities

2004 ◽  
Author(s):  
Stefano Beretta ◽  
Herna´n Juan Desimone ◽  
Andrea Poli
Keyword(s):  
Fatigue Limit ◽  
Detrimental Effect ◽  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Probability Of Failure ◽  
Integral Approach ◽  
Material Strength ◽  
Automotive Components ◽  
Tubular Components

Tubular automotive components, e.g. stabilizers and half shafts, are components subjected to fatigue. In order to assess fatigue behavior of such components, it is important to know both the real load conditions as well as the material strength against multi-axial fatigue. For the second point, a detrimental effect in the fatigue limit of high strength steels is given by the defects present in the component, coming from the material (such as microinclusions, microvoids, etc) or for the process (e.g. handling marks). An integral approach in order to assess fatigue limit of tubular components is proposed. The attention is focused onto planar inhomogeneities, which are the most common in tubular products, though the methodology can be extended to different defect-shapes. The method is applied together with a probabilistic model, in order to analyze the probability of failure. In particular, two different processes (in terms of inhomogeneities present in the final component) are compared, and the results allow to evaluate, for example, the admissible load for the desired (or design) level of failure probability for the component.

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