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).

Hydrogen Induced Stress Cracking (HISC) of Stainless Steels Under Cathodic Protection in Seawater: Presentation of a New Test Method

2009 ◽  
Author(s):  
Roy Johnsen ◽  
Ba˚rd Nyhus ◽  
Stig Wa¨stberg
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Cathodic Protection ◽  
Stainless Steels ◽  
Production Systems ◽  
Oil Industry ◽  
Test Method ◽  
Stress Cracking ◽  
Induced Stress ◽  
Subsea Pipelines

There has been an increasing trend in the use of stainless steel alloys instead of carbon steel for subsea flowlines and production systems during the last 15 years in the oil industry. Even if this normally is a more robust solution compared to the use of carbon steel insofar as internal corrosion problems are concerned, the use of stainless steels has led to leakage, production shutdown and expensive repair work. The reported failures were associated with hydrogen entrapment resulting from welding and/or external cathodic protection (CP), combined with a certain stress/strain level. Atomic hydrogen entering the alloy can weaken the mechanical strength of the alloy, cause cracks and destroy the integrity of equipment or a system. Such failures attributed to hydrogen induced stress cracking (HISC) are clearly not acceptable from the perspective of safety, environmental hazard and cost. Leading oil and engineering companies and supplier industry have pointed out HISC as one of the major obstacles against safe operation of stainless steel subsea pipelines and production systems. It is important for the oil industry to have design guidelines and reliable test method(s) for qualification and safe utilization of subsea pipelines and components made from the actual stainless steels. This paper describes a test method that has been developed through a Joint Industry Project (JIP) executed by SINTEF and Det Norske Veritas (DNV) with support from leading oil companies and material suppliers. The method has been qualified for use on 13% Cr super martensitic (SMSS) and 22% Cr / 25% Cr duplex stainless steels (DSS/SDSS). The link to DNV-RP-F112 [1] will also be described.

Hydrogen Induced Stress Cracking of Superduplex Steels: Effect of Operation Temperature

2018 ◽  
Author(s):  
Lars M. Haldorsen ◽  
Bård Nyhus ◽  
Gisle Rørvik
Keyword(s):  
Cathodic Protection ◽  
Life Time ◽  
Oil Companies ◽  
Stress Cracking ◽  
Operation Temperature ◽  
Induced Stress ◽  
Duplex Steel ◽  
Future Revision ◽  
Cathodic Protection System ◽  
Guidelines And Recommendations

Duplex stainless steel has been used on subsea facilities since the mid 80-ties. The experiences with these materials have been relative good and only a few failures have been reported. However, BP and Shell experience some serious cracking of duplex steel in the mid 90-ties and in beginning of the century. The root cause of these failures was identified to be Hydrogen Induced Stress Cracking, HISC, where the hydrogen source was the cathodic protection system of the subsea facility. These and other similar failures resulted establishment of Joint Industry Projects, JIPs with financial and technical contribution from leading oil companies, contractors, material suppliers and research institutions as TWI, SINTEF and DNVGL. The objective of the JIPs was to establish practical usage limits for duplex stainless steels. The JIPs resulted in a recommended practice “DNV-RP-F112 - Design of duplex stainless subsea equipment exposed to cathodic protection.” This document minimized the failure rate of duplex steel components used subsea. However, since duplex steels components have been used on subsea facilities long before the guidelines and recommendations were issued, there are lot of components presently in use that may be overloaded compared to guidelines and recommendations. As a part of life time extension of one of Statoil’s long time producing fields, a HISC re-calculation of spools connecting SPSs to infield pipelines showed that many of the spools were exposed to stresses above the recommended stresses given in DNV-RP-F112. Since these recommendations were primarily based on testing at ambient seabed temperature (4°C), Statoil, together with SINTEF, started in 2016 a project where the aim was to evaluate the resistance against HISC as an effect of the operation temperature. The results of this project show that the critical net section stress/AYS (HISC resistance) increases with increasing temperature. Based on this, the before mentioned spools can be considered safe even though the spools are exposed to stresses above the recommendations in DNV-RP-F112. Further, the investigations show that the guidelines and recommendations given in DNV-RP-F112 may be conservative for temperatures above 4°C. It is therefore recommended to perform more testing to confirm and incorporate the findings from the present investigation in future revision of DNV-RP-F112.

Resistance Toward Hydrogen-Induced Stress Cracking of Hot Isostatically Pressed Duplex Stainless Steels Under Cathodic Protection

CORROSION ◽  
2010 ◽  
Vol 66 (11) ◽  
pp. 115004-115004-13 ◽  
Author(s):  
GØ Lauvstad ◽  
R. Johnsen ◽  
I. Asbjørnsen ◽  
M. Bjurström ◽  
C.-G. Hjorth
Keyword(s):  
Cathodic Protection ◽  
Stainless Steels ◽  
Duplex Stainless Steels ◽  
Stress Cracking ◽  
Induced Stress

The Successful Use of Austenitic Stainless Steels in Sea Water

1977 ◽  
Vol 17 (02) ◽  
pp. 101-110 ◽  
Author(s):  
G.E. Moller
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cathodic Protection ◽  
Stainless Steels ◽  
Sea Water ◽  
Austenitic Stainless Steels ◽  
Pump Impeller ◽  
Ocean Science ◽  
Free Service ◽  
Selection Of

Moller, G.E., International Nickel Co., Inc., Torrance, Calif. Abstract Austenitic stainless steels are providing excellent trouble-free service in sea water for pumps, propellers, valves. and other marine equipment. propellers, valves. and other marine equipment. Occasionally, a failure occurs as the result of deep localized pitting in a crevice. Data are given showing that austenitic, ferritic. and martensitic stainless steels suffer pitting in crevices and under deposits in quiescent sea water. Austenitic stainless steels remain free from attack in high-velocity sea water. Low-purity ferritic and the martensitic stainless steels frequently pit in high-velocity sea water. Crevice corrosion can be controlled effectively with cathodic protection from iron, zinc. aluminum or magnesium galvanic anodes or impressed current cathodic protection by polarization to -0.6 v vs Calomel. Austenitic stainless steel performs well in many situations because it is a component of a multi-alloy assembly utilizing iron or steel. Examples from field experience arc given. Introduction During the past decade, there has been a growing use of austenitic stainless steel in marine equipment. Most applications have been successful but an unexpected failure has been observed occasionally. It is the purpose of this paper to describe when and how to use austenitic stainless steel with success. The selection of stainless steels appears to result from the engineering requirements of new, advanced, high-speed, high-reliability commercial, pleasure, and military craft. Ocean science and pleasure, and military craft. Ocean science and engineering, offshore oil production, fishing, and ocean mining are also contributing to the selection of stainless steels for sea-water applications. The increasing use of stainless steel in the marine environment is found in work-boat propellers, pump components, bow thrusters, valves, shafting pump components, bow thrusters, valves, shafting and shaft components, through-hull fittings, parts on data-gathering buoys, fasteners, and housings of oceanographic instruments. When austenitic stainless steel has given good, corrosion-free service, it is most often found to be used as a key component in a multi component, multi-alloy assembly or system receiving the benefit of built-in cathodic protection. For example, in Fig. 1 a cast Type 304 (Alloy Casting Institute CF-4) propeller is being used on a steel seagoing tugboat with zinc anodes attached to the rudder. Fig. 2 shows a cast ACI CE-30 power-plant sea-water circulation-pump impeller free power-plant sea-water circulation-pump impeller free of any corrosion after 6 years of service that was used in combination with an austenitic cast-iron suction bell and diffuser. SPEJ p. 101

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

scholarly journals A Study on Unification of Welding Consumables in Construction of Chemical Cargo Tanker Made of Duplex Stainless Steel: Evaluation of Static Strength of Welded Joint

2019 ◽  
Author(s):  
Takayuki Yotsuzuka ◽  
Yusuke Endo ◽  
Eiji Niino ◽  
Koji Gotoh
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Static Strength ◽  
Clad Steels ◽  
Clad Steel ◽  
Welding Consumables ◽  
Welding Materials

Abstract Austenitic stainless steels such as SUS 316 LN and austenitic stainless clad steel are used in cargo holds of chemical tankers owing to their corrosion resistance. Recently, the use of duplex stainless steels has been increasing, owing to their better strength and corrosion resistance and lower content of expensive Ni, compared with those features of austenitic stainless steels. However, few duplex stainless clad steels have been approved by classification bodies. Furthermore, the application of duplex stainless steel is not yet mainstream as hull structural materials because a stable supply market has yet to be established. Therefore, when applying cladding steel to construction of chemical tankers, austenitic stainless clad steel is often used at present. The duplex stainless steel and the austenitic stainless clad steel are mixed at construction factories; hence, there is a risk of misuse of welding consumables. If misuse is suspected, it is not possible to judge the erroneous use from visual inspection after construction; therefore it is necessary to uniformly remove the weld and re-weld. However, if universal welding consumables were identified, this might avoid the problems of misuse and simplify the procurement of welding materials. In this paper, we report on our studies to verify welding consumables for use in the hull structures, involving a mixture of duplex stainless steel and the austenitic stainless clad steel. The static strength of the welded joints is a particular focus of this study, from which we confirmed the validity and limitations of welding consumables.

Avoiding Hydrogen Embrittlement Stress Cracking of Ferritic Austenitic Stainless Steels Under Cathodic Protection

2004 ◽  
Author(s):  
P. Woollin ◽  
A. Gregori
Keyword(s):  
Hydrogen Embrittlement ◽  
Cathodic Protection ◽  
Stainless Steels ◽  
Large Scale ◽  
Austenitic Stainless Steels ◽  
Austenitic Steels ◽  
Stress Cracking ◽  
Initiation And Propagation ◽  
Phase Balance ◽  
Large Scale Tests

The paper presents the results of a programme designed to define the material, stress and environmental factors controlling sensitivity of ferritic-austenitic stainless steels to hydrogen embrittlement stress cracking when exposed to cathodic protection. Factors examined in small and large-scale tests include microstructural coarseness, phase balance and hardness of a range of parent steels and welds. The results are presented in terms of threshold strain and normalised stress to develop hydrogen embrittlement stress cracks. The effects of microstructure and applied potential on crack initiation and propagation are described. Recommendations are made with respect to the strain/normalised stress levels for ferritic-austenitic steels under cathodic protection.

scholarly journals Weldability of duplex stainless steels- A review

2021 ◽  
Vol 309 ◽  
pp. 01076
Author(s):  
Aditya Ramesh ◽  
Vishal Kumar ◽  
Anuj ◽  
Pradeep Khanna
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Duplex Stainless Steels ◽  
Austenite Formation ◽  
Industrial Sectors ◽  
Temperature Heat ◽  
High Production ◽  
Corrosive Resistance

Duplex stainless steel finds widespread use in various sectors of manufacturing and related fields. It has many advantages due to its distinctive structural combination of austenite and ferrite grains. It is the need of the current generation due to its better corrosive resistance over high production austenitic stainless steels. This paper reviews the weldability of duplex stainless steels, mentions the reason behind the need for duplex stainless steels and describes how it came into existence. The transformations in the heat-affected zones during the welding of duplex stainless steels have also been covered in this paper. The formation, microstructure and changes in high temperature and low temperature heat-affected zones have been reviewed in extensive detail. The effects of cooling rate on austenite formation has been briefly discussed. A comparison of weldability between austenitic and duplex stainless steel is also given. Finally, the paper reviews the applications of the various grades of duplex stainless steel in a variety of industries like chemical, paper and power generation and discusses the future scope of duplex stainless steel in various industrial sectors.

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