Hydrogen induced stress cracking of duplex stainless steel subsea components

Loadcontrol situations occur in the absence of restraints on continuous material straining, such as for. Hydrogeninduced cracking an overview sciencedirect topics. A number of notable failure cases have however drawn attention to the risk of hydrogen embrittlement or hydrogen induced stress cracking hisc associated with the use of duplex stainless steels for subsea components that are exposed to external cathodic protection cp. The results showed that the failure developed from a combination of factors, typical for hydrogeninduced stress cracking. Abstract a recent subsea failure of two subsea connectors made of uns s32760, a 25 wt% cr super duplex stainless steel, led to an extensive root cause failure analysis. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. A number of notable failure cases have however drawn attention to the risk of hydrogen embrittlement or hydrogen induced stress cracking hisc associated with the use of duplex stainless steels for subsea components that are exposed to external cathodic protection. Hydrogen induced stress cracking of swaged 25cr super duplex. Aug 01, 2019 hydrogen induced stress cracking of swaged super duplex stainless steel subsea components, corrosion 757. Hydrogen induced stress cracking in uns s32750 super. Corrosion control of subsea production control systems.

Hydrogen induced stress cracking of super duplex stainless. Hydrogeninduced stress cracking of swaged super duplex stainless steel subsea components. A recent subsea failure of two coupling assembly flanges made of uns s32760, a 25 wt% cr super duplex stainless steel, led to an extensive root cause failure analysis. Hydrogen induced stress cracking hisc and dnvrpf112. Hydrogen induced stress cracking for duplex stainless. Industry subsea failures have resulted from hisc under loadcontrol scenarios where local strain levels exceed a critical strain threshold. Hydrogen stress cracking can affect several different types of metals such as high strength structural, carbon, and low alloy steels, along with titanium, nickel, and aluminium alloys.

The measured hydrogen content in parts of the material exceeded 40 ppm, more than an order of magnitude higher than what is normally expected in super duplex stainless steels. Hansen1, consequences of sigma phase on pitting corrosion resistance of duplex stainless steel, 1force technology, department of corrosion and metallurgy, 2605 brondby, denmark. Hydrogen induced stress cracking of duplex stainless steel in. There are several types of stress corrosion cracking scc, for example, chloride induced scc and h 2 s induced scc. About corrosion all about corrosion science and engineering.

Also high strength structural steels which are welded are exposed to a certain hydrogen pickup which means a risk at fracture and blistering. Stress based design guidelines for hydrogen induced stress. This paper describes a method that has been developed through a jip. The blistering damage tends to form parallel to the surface and to the direction of hoop stress. Duplex stainless steels 22cr duplex and 25cr super duplex are susceptible to hydrogen induced stress cracking hisc under cathodic protection cp. 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. A small number of duplex and superduplex stainless steel components have failed in subsea service due to hydrogen induced stress cracking hisc. Hydrogen induced stress cracking of swaged super duplex stainless steel subsea components, corrosion. Oilgas training subsea, risers and umbillicals hydrogen induced stress cracking hisc design and material consideration course 1 day this hisc course is based on dnvglrpf112 duplex stainless steel design against hydrogen induced stress cracking. Dnvglrpf112 duplex stainless steel design against hydrogen induced stress cracking recommended practice this recommended practice rp covers the design of components made from duplex stainless steels that are installed subsea and are exposed to cathodic protection.

Our hydrogen embrittlement testing labs can carry out hisc testing of nickel alloys and duplex stainless steels, widely used in subsea components, to. One reason for this is smaller austenite spacing of the hot isostatic pressed material that is typically below 15 m. Shinozaki k, ke l and north t h, hydrogen cracking in duplex stainless steel weld metal, welding journal 1992, 71. Hydrogen embrittlement cracking of superduplex steel twi. Hydrogen induced stress cracking hisc of duplex material 1 day. Experiences with hydrogen induced stress cracking of.

A comprehensive test program is fp quantifying the hisc performance of retrieved superduplex stainless steel subsea components and, comparing the actual performance against the limits derived following dnv rp f in the presence of a critical hydrogen concentration, all duplex and super duplex stainless. Sep 25, 2018 however, bp and shell experience some serious cracking of duplex steel in the mid 90ties and in beginning of the century. Hydrogen induced stress cracking in uns s32750 super duplex. A recent subsea failure of two subsea connectors made of uns s32760, a 25 wt% cr super duplex stainless steel, led to an extensive root cause failure analysis.

May 07, 2019 duplex stainless steels 22cr duplex and 25cr super duplex are susceptible to hydrogen induced stress cracking hisc under cathodic protection cp. Astm f519 hydrogen embrittlement he testing element. Hydrogen cracking in duplex stainless steel weld metal. Blanchard duplex stainless steels dsss are widely used by oil and gas industry due to their good corrosion and mechanical properties, which made them suitable for subsea applications. Hydrogen cracking of welds in duplex stainless steels, proc conf. Note 2 the austenite spacing is relevant to the susceptibility of duplex stainless steels to hydrogen induced stress cracking hisc in subsea applications where cathodic protection is applied. Super duplex stainless steel s32760 advanced forging process. Alloys for offshore applications duplex and super duplex. Hydrogen induced stress cracking of duplex stainless steel. Photomicrograph of chlorideinduced stress corrosion cracking in 316 stainless steel 100x magnification. Hydrogen induced stress cracking for duplex stainless steel.

Smss and 22% cr 25% cr duplex stainless steels dsssdss. Duplex and superduplex stainless steels, why is everyone so. Huang j h and altstetter c j, cracking of duplex stainless steel due to dissolved hydrogen, met trans a, 26a may 1995, p1079. Hydrogen induced stress cracking, duplex stainless steel. The failures have been due to hydrogen induced stress cracking hisc.

Duplex stainless steels are widely used in subsea petro leum production. Hydrogeninduced stress cracking hisc issues should be addresses for duplex stainless steel pipework exposed to cathodic protection. Duplex stainless steel design against hydrogen induced stress cracking. The design requirements in hisc hydrogen induced stress considerations 1 day course based on dnvrpf112 design of duplex stainless steel subsea equipment exposed to cathodic protection. Hisc hydrogen induced stress considerations subsea uk. Abstract a recent subsea failure of two coupling assembly flanges made of uns s32760, a 25 wt% cr super duplex stainless steel, lead to an extensive root cause failure analysis. Fundamentals of hydrogen induced stress cracking in duplex stainless steels 20190219t12. Hydrogen induced cracking of subsea duplex stainless steel. Zeron 100 uns s 32760 modified, advanced forging process afp, super duplex stainless steel for increased low temperature impact toughness and resistance to hydrogen induced stress corrosion cracking hiscc of api forgings for subsea applications. Experiences with hydrogen induced stress cracking of duplex. Hydrogen induced stress cracking hisc and dnvrpf112 hydrogen induced stress cracking hisc and dnvrpf112 abstractexecutive summary duplex stainless steels are widely used in subsea petroleum production installation. Welding may cause increased hydrogen induced stress cracking susceptibility in the weld metal and in the haz adjacent to the fusion line. Ostbyapplication of hydrogen influenced cohesive laws in the prediction of hydrogen induced stress cracking in 25%cr duplex stainless steel eng fract mech, 75 8 2008, pp. There was a total of 198 such forgings deployed the cracking was found to be subsea.

Hydrogen induced stress cracking hisc resistance and. The duplex stainless steels are susceptible to hisc when exposed to elevated stresses in conjunction with cathodic protection potentials lower than typically 850 mv relative to the agagclseawater reference. Hydrogeninduced cracking hic in steel is a risk problem when steels are charged with hydrogen in service as in various hydrogen sulfide environments like sour oil and gas wells and some power plants. Hisc is the achilles heel of duplex and super duplex stainless steels. This penetration can lead to the brittle fracture of materials that are normally ductile when hydrogen happens to be present in their environment. The effects of notches and welds on hydrogen embrittlement stress cracking of duplex stainless steels, sintefdnv. Abstract a recent subsea failure of two subsea connectors made of uns s32760, a 25 wt% cr super duplex.

Jun 27, 2019 a recent subsea failure of two coupling assembly flanges made of uns s32760, a 25 wt% cr super duplex stainless steel, led to an extensive root cause failure analysis. Duplex stainless steel design against hydrogen induced stress cracking this rp covers the design of components made from duplex stainless steels that are installed subsea and are exposed to cathodic protection, by. Stress corrosion cracking facts and how to reduce the risk. Hydrogen induced cracking hic is a common form of wet h2s cracking caused by the blistering of a metal due to a high concentration of hydrogen. Hydrogen induced stress cracking hisc of stainless steels under.

Duplex and superduplex stainless steels, why is everyone. Hydrogen induced stress cracking hisc has been experienced on duplex stainless steels and supermartensittic stainless steels under cathodic protection cp in seawater. The significance of these failures has led to research aimed at defining critical conditions for hisc, to allow confident design of components in future. Hydrogen induced cracking of subsea duplex stainless steel twi. Nov 20, 2002 it has also been suggested that a documented example of cracking in high strength steel legs of jackup rigs was associated with hydrogen induced stress corrosion cracking, the hydrogen being generated by the cathodic protection system operating in hydrogen sulphide contaminated seawater february 1989 issue of veritec offshore technology journal. The components showed a single longitudinal crack along the swaged ferrule, which arrested towards its thicker section. Stress corrosion cracking scc is characterized by cracks propagating either transgranularly or intergranularly along grain boundaries. Hydrogen induced stress cracking, duplex stainless steel, cathodic protection, seawater, field failures, lessons learned. It has also been suggested that a documented example of cracking in high strength steel legs of jackup rigs was associated with hydrogeninduced stress corrosion cracking, the hydrogen being generated by the cathodic protection system operating in hydrogen sulphide contaminated seawater february 1989 issue of veritec offshore technology journal. It involves the ingress of hydrogen into a component, an event that can seriously reduce the ductility and loadbearing capacity, cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. Hsc is a form of environmentally assisted cracking in which a ductilealbeit susceptiblematerial could exhibit fast brittle failure when exposed to hydrogenbearing environments under particular loading conditions. To understand the corrosion resistance properties of duplex stainless steel, you must also understand the concept of stress corrosion cracking.

Other applications where sulfide species have produced environmental cracking include heavy water production, electric power, marine. The requirements for ssc to occur are not unlike those for scc. Austenitic and ferritic duplex stainless steels, dss, have recently suffered from hydrogen stress induced cracking, hisc, in subsea components with a cathodic protection. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments. Validation of dnv rp f112 for managing hydrogen induced stress cracking hisc in super duplex stainless steel for subsea applications. Amir bahrami and paul woollin, hydrogen induced stress cracking of duplex stainless steel subsea components, twi ltd, cambridge, uk. Apr 04, 2019 hydrogeninduced stress cracking of swaged super duplex stainless steel subsea components august 1, 2019 by mariano iannuzzi hisc is the achilles heel of duplex and super duplex stainless steels. Validation of dnv rp f112 for managing hydrogen induced. Not only can duplex stainless steel hold up reliably through trauma impact, but through corrosion as well. Hydrogen induced stress cracking hisc resistance and improvement.

Fundamentals of hydrogen induced stress cracking in duplex. Hydrogeninduced stress cracking of swaged super duplex. Hydrogeninduced stress cracking of swaged super duplex stainless steel subsea components article pdf available in corrosion houston tx 757 august 2019 with 181 reads how we measure reads. Hydrogen induced cracking hic in steel is a risk problem when steels are charged with hydrogen in service as in various hydrogen sulfide environments like sour oil and gas wells and some power plants. This paper examines the factors determining weld metal hydrogen cracking. Hydrogen cracking of ferriticaustenitic stainless steel. Connection between critical stress and hydrogen content. Pdf hydrogeninduced stress cracking of swaged super duplex. Ferriticaustenitic duplex stainless steels should be regarded as potentially susceptible to hydrogen induced stress cracking, independent of smys typically 400 to 550 mpa or specified maximum hardness. The components showed a single longitudinal crack along the swaged ferr. Hydrogen induced stress cracking of swaged super duplex. Cracking was induced in the hubs by exceeding these threshold values locally at a notch. Hydrogen induced stress cracking of swaged 25cr super duplex stainless steel subsea endfittings available for download in 2018 the apparent failure of two subsea jumper endfittings was detected by remotely operated vehicle rov inspection prompting their retrieval from the seabed for analysis.

The significance of these failures has led to research to define critical loading conditions for hisc, to allow confident design of components in future. Hisc hydrogen charging from the cathodic protection system in the presence of creep strains embrittles the duplex steel, making the duplex susceptible to cracking hydrogeninducedstresscracking, hisc. Hydrogen stress cracking is a form of hydrogen embrittlement that occurs when corrosion from acids like wet hydrogen sulfide and hydrofluoric acid cause atomic hydrogen to penetrate hardened or higher strength steels and cause stress cracking. Previous work using slow strain rate testing3,4 had shown that these grades were susceptible to hydrogen embrittlement when exposed to cp s below 700mv sce. Hydrogen induced stress cracking hisc of duplex material 1.

In a very similar manner, ssc requires a susceptible material. In recent years super duplex stainless steel sdss installed subsea with cathodic protection has failed during service. Abstract ferriticaustenitic duplex and superduplex stainless steels dsss and sdsss are an attractive option for subsea equipment and connecting spools, in which the internal corrosion threats can be difficult to manage, using corrosion inhibiti. Powder metal based, hot isostatic pressed duplex stainless steels generally have better resistance to hydrogen induced stress corrosion cracking than forged or cast material duplex stainless steel. Hydrogen induced stress cracking of superduplex steels.

A corrosive medium especially chloridebearing or hydrogen sulphide h 2 s media. Stress corrosion cracking in duplex stainless steel. This paper provides discussions on possible hisc mechanisms. Ferritic stainless steels, on the other hand, tend to be fairly resistant to hydrogen stress cracking due to their comparatively low hardness. A recent subsea failure of two subsea connectors made of uns s32760, a 25 wt% cr super duplex. The results showed that the failure developed from a combination of factors, typical for hydrogen induced stress cracking. The effect from different protection potentials and hydrogen content has been. Hydrogen induced stress cracking civilweb spreadsheets. In many instances such steels are a robust solution to the design and manufacturing challenges. Hydrogen induced stress cracking hisc of duplex material.

In this investigation, we demonstrate the detrimental effects of both cold work swaging and anisotropic microstructures on hisc resistance. Hydrogeninduced stress cracking of swaged super duplex stainless steel subsea components, corrosion 757. This rp covers the design of components made from duplex stainless steels that are installed subsea and are exposed to cathodic protection, by. Hydrogen induced stress cracking hisc rolled alloys, inc. Mechanisms of hydrogen induced stress crack initiation and. Duplex stainless steel has become more and more popular for its combination of strength and affordability.