Cohesive zone modeling of hydrogen-induced stress cracking in 25% Cr duplex stainless steel

2007 ◽  
Vol 57 (7) ◽  
pp. 615-618 ◽  
Author(s):  
Vigdis Olden ◽  
Christian Thaulow ◽  
Roy Johnsen ◽  
Erling Østby
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cohesive Zone ◽  
Cohesive Zone Modeling ◽  
Stress Cracking ◽  
Induced Stress ◽  
Zone Modeling

A Cohesive Zone Modeling Approach to Hydrogen Induced Stress Cracking in 25%Cr Duplex Stainless Steel

2007 ◽  
Author(s):  
Vigdis Olden ◽  
Christian Thaulow ◽  
Roy Johnsen ◽  
Erling O̸stby
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cohesive Zone ◽  
Oil And Gas ◽  
Fracture Initiation ◽  
Cohesive Zone Modeling ◽  
Fine Grained ◽  
Stress Cracking ◽  
Step Procedure ◽  
Cohesive Zone Elements

Hydrogen influenced cohesive zone elements are implemented in finite element (FE) models of rectangular U and V notched tensile specimens. The material description outside the cohesive zone is representative of a fine grained 25% Cr duplex stainless steel, UNS32760-S. A three step procedure consisting of conventional elastic plastic stress analysis, stress driven diffusion analysis and finally cohesive zone fracture initiation analysis makes the basis for the presented work. The applied boundary conditions are representative of mechanical stresses and environmental loads on an oil and gas pipeline in subsea conditions. A linear traction separation law gives reasonably good fit with experimental results for gross stress levels of 0.85–0.9 times the material yield stress. Hydrogen concentration of 40 ppm at the surface and 1 ppm in bulk always gives crack initiation at the surface despite the peak normal stress localized in front of the notch tip.

Hydrogen Induced Stress Cracking (HISC) in Duplex Stainless Steels: DNV-RP-F112, Design of Duplex Stainless Steel Subsea Equipment Exposed to Cathodic Protection

2009 ◽  
Author(s):  
Stig Wa¨stberg ◽  
Morten Solno̸rdal ◽  
Gustav Heiberg ◽  
Rikard To¨rnqvist ◽  
Pedro M. Vargas
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cathodic Protection ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Design Guideline ◽  
Oil Companies ◽  
Stress Cracking ◽  
Induced Stress ◽  
Offshore Industry

Both 22Cr and 25Cr duplex (ferritic-austenitic) stainless steels have been extensively used for subsea equipment. In general the experience is good but some significant failures have occurred where Hydrogen Induced Stress Cracking (HISC) have been identified as a contributing factor. Because of these failures there was identified a need within the offshore industry for a design guideline treating HISC as a failure mode and reflecting best practice based on today’s knowledge, experience from in-service failures and recent research. The paper starts with a brief review of some of the failures and the main results from the comprehensive test program in the HISC JIP conducted in cooperation between Sintef and DNV. The JIP is supported by several major oil companies, subsea contractors and material suppliers and constitute the main scientific background for the recently issued Recommended Practice, DNV-RP-F112, Design of Duplex Stainless Steel Subsea Equipment Exposed to Cathodic Protection (October 2008).

Effect of Weld Porosity on Super Duplex Stainless Steel Umbilical Tubes Under Hydrogen Induced Stress Cracking Exposure Condition

2019 ◽  
Author(s):  
M. Socariceanu ◽  
X. An
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
Slow Strain Rate ◽  
Exposure Condition ◽  
Super Duplex Stainless Steel ◽  
Stress Cracking ◽  
Induced Stress ◽  
Weld Porosity ◽  
The Impact

Abstract Super Duplex Stainless Steel (SDSS) is the preferred material utilized in steel tube umbilicals, due to its excellent corrosion resistance and high mechanical strength. SDSS is susceptible to Hydrogen Induced Stress Cracking (HISC) under the influence of a Cathodic Protection (CP) system, especially the welded zone. Porosity (relevant rounded indication) is one of the most common weld flaws that impacts the SDSS weld reject rate based on historical acceptance criteria. A study has been carried out investigating the influence of weld porosity on 25% Cr (SDSS) butt welded tube, under the effect of CP potential by using a Slow Strain Rate Testing (SSRT) technique. The study focused on the correlation between the level of porosity and the material mechanical performance when exposed to a simulated CP system in seawater at an elevated temperature. The impact of HISC was evaluated through an assessment of various tube welds including welds with different levels of porosity quantified by number, size and location of pores, when exposed directly to natural CP system in seawater for 4 and 8 weeks. Post hydrogen pre-charging, the samples were subjected immediately to a modified Slow Strain Rate Test (SSRT). After hydrogen charging and SSRT the resulting fracture morphology was examined using a scanning electron microscope (SEM), and the failure mode was assessed in relation to porosity locations. Experimental results indicate that all hydrogen pre-charged samples with or without pores decrease in ductility after exposure to the CP system which was further confirmed by the fractography analysis. It was observed that susceptibility of SDSS to HISC is broadly similar for welds with porosity or without porosity and brittle phenomena is more pronounced at the exposed surfaces of the samples. The study has demonstrated that the butt weld of SDSS umbilical tube with a controlled porosity level in line with ASME design codes does not show an increased susceptibility to HISC under CP system when compared to welds with no porosity.

Application of hydrogen influenced cohesive laws in the prediction of hydrogen induced stress cracking in 25%Cr duplex stainless steel

2008 ◽  
Vol 75 (8) ◽  
pp. 2333-2351 ◽  
Author(s):  
Vigdis Olden ◽  
Christian Thaulow ◽  
Roy Johnsen ◽  
Erling Østby ◽  
Torodd Berstad
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Stress Cracking ◽  
Induced Stress ◽  
Cohesive Laws

scholarly journals Hydrogen-Induced Stress Cracking of Swaged Super Duplex Stainless Steel Subsea Components

CORROSION ◽  
10.5006/3192 ◽  
2019 ◽  
Vol 75 (7) ◽  
pp. 824-838 ◽  
Author(s):  
M. Sofia Hazarabedian ◽  
Andreas Viereckl ◽  
Zakaria Quadir ◽  
Garry Leadbeater ◽  
Vladimir Golovanevskiy ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Super Duplex Stainless Steel ◽  
Stress Cracking ◽  
Induced Stress

scholarly journals Selected Aspects of Cohesive Zone Modeling in Fracture Mechanics

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 302
Author(s):  
Wiktor Wciślik ◽  
Tadeusz Pała
Keyword(s):  
Cohesive Zone ◽  
Mixed Mode ◽  
Review Paper ◽  
Failure Process ◽  
Cohesive Zone Modeling ◽  
Mixed Mode Loading ◽  
Cohesive Models ◽  
Cohesive Modeling ◽  
Zone Modeling ◽  
Intensive Development

This review paper discusses the basic problems related to the use of cohesive models to simulate the initiation and development of failure in various types of engineering issues. The most commonly used cohesive zone models (CZMs) are described. Recent achievements in the field of cohesive modeling are characterized, with particular emphasis on the problem of mixed mode loading, the influence of the strain rate, the stress state triaxiality, and fatigue. A separate chapter of the work is devoted to the identification of cohesive parameters. Examples of the use of CZMs for the analysis of the fracture and failure process in various applications, both on the macro and microscopic scale, are given. The directions of CZMs development were indicated as well as the issues that are currently under particularly intensive development.

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