Only the 25% nickel grades have similar cscc resistance. General corrosion tests are insensitive to detection of localized corrosion and are not always adequate for determining material compatibility for coriolis meters. Ssc6mo uns n08367 is a superaustenitic 6% molybdenum alloy that exhibits far greater resistance to chloride pitting, crevice corrosion and stress corrosion cracking than the standard 300 series and standard duplex stainless steels. Stress corrosion cracking scc of duplex stainless steel. Prevention of scc stress corrosion cracking failure is the joint responsibility of the designer, structural engineer and pool operator.
Stainless steels are damaged by stress corrosion cracking in conditions containing chlorides at the high temperatures. Hydrogeninduced stress cracking of swaged super duplex. Oct 21, 2019 chloride stress corrosion cracking is a localized corrosion mechanism like pitting and crevice corrosion. Increasing nickel content above 18 to 20% or the use of duplex, or ferritic stainless steels improves resistance to cscc. Pdf stresscorrosion cracking behaviour of leanduplex.
The susceptibility of 22 cr and 25 cr duplex stainless steels to stress corrosion cracking under evaporative seawater conditions has been evaluated using a modified drop evaporation test. Greater corrosion resistance particularly stress corrosion cracking. C for 500 h under drops of synthetic seawater det, drop evaporation test. Hydrogen embrittlement cracking of superduplex steel twi. G30 practice for making and using ubend stress corrosion test specimens. Threshold temperature for stress corrosion cracking of duplex. Stress corrosion cracking scc is a progressive fracturing that occurs in metals as a result of the combined influence of tensile stress and a corrosive environment. Turnbull, threshold temperature for stress corrosion cracking of duplex stainless steel under evaporative seawater conditions, corrosion. It also demonstrates good fatigue strength, as well as outstanding resistance to stress corrosion cracking, crevice, pitting, erosion, and general corrosion in severe environments.
It occurs in austenitic stainless steel under tensile stress in. Stress corrosion cracking of ldx 2101 duplex stainless. The stress corrosion cracking scc behaviour of two lean duplex stainless steels dss 2304 and ldss 2404 was studied by slow strainrate tests ssrt. Structural failure due to scc can be very unpredictablefailure could occur after as little as a few hours of exposure, or the equipment could continue to function normally for.
Stress corrosion cracking scc is the cracking induced from the combined influence of tensile stress and a corrosive environment. Hydrogeninduced stress cracking of swaged super duplex stainless steel subsea components, corrosion. The stresscorrosion cracking scc behaviour of two leanduplex stainless steels dss 2304 and ldss 2404 was studied by slow strainrate tests ssrt in 20% nacl solution at 80 c ph about 6. Abstract duplex stainless steel is widely used in the oil and gas industry due to its inherent resistance to localised corrosion and stress corrosion cracking. Corrosionpedia what is stress corrosion cracking scc. Stress corrosion cracking of duplex stainless steels in. G15 terminology relating to corrosion and corrosion testing. The stress corrosion cracking of duplex stainless steel in h2sco2cl. The manufacturer offers a duplex stainless steel screw that mixes austenite and ferrite stainless, thereby bestowing on it the advantages of highstrength and corrosion resistance. Stress corrosion cracking of ductile niresist irons and. It is the most widely used duplex stainless steel grade and is characterized by high yield strength, double that of the standard austenitic stainless steel grades. Stress corrosion cracking facts and how to reduce the risk. It offers outstanding resistance to the chloride ion stress cracking at temperature ranges to 150oc.
Stress corrosion cracking scc is a common issue with many specialty alloys. Residual stress and elasticplastic behavior of duplex stainless steels. Chloride stress corrosion cracking clscc is one the most common reasons why austenitic stainless steel pipework and vessels deteriorate in the chemical processing and petrochemical industries. Pitting, intergranular attack, stress corrosion cracking, and corrosion fatigue are all forms of localized corrosion that can lead to meter failure. Abstract stress corrosion cracking scc induced by chlorides frequently causes problems in applications where standard austenitic stainless steels are being. Superior to 2205 in corrosion resistance and strength. The iron sulfide is cathodic to steel, contributing to pitting corrosion of scalefree areas. Stress corrosion cracking in duplex stainless steel great. Hydrogen induced cracking of subsea duplex stainless steel. Pdf threshold temperature for stress corrosion cracking. Methods of minimizing chloride stress corrosion cracking. Ss2205 is a duplex stainless steel with a microstructure, when heat treated properly, of nearly equal proportions of austenite and ferrite. The standard 304304l and 316316l grades are most susceptible. Grade selection to avoid scc involves considering grades such as 1.
Deterioration by clscc can lead to failures that have the potential to release stored energy andor hazardous substances. Stress corrosion cracking behaviour of lean duplex. Lets discuss the concept of stress corrosion cracking and what it entails, and how it relates to duplex. What is stresscorrosion cracking and why does it occur. Chloride stress corrosion cracking cscc is a type of intergranular corrosion. Duplex stainless steels are a family of stainless steels. Not only can duplex stainless steel hold up reliably through trauma impact, but through corrosion as well. Scc is often associated with chlorides, but can also occur with caustics and other corrosive media. The resistance of austenitic and ferritic stainless steels to chloride stress corrosion cracking has been correlated to the nickel content of the alloys. Mechanical properties the duplex structure of 2205 gives it signi. The combination of tensile stress and a specific corrosive environment can crack stainless steels.
Super duplex and super austenitic stainless steels are considered virtually immune to chloride 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. Duplex stainless steel has become more popular for its combination of strength and affordability. Polythionic acid stress corrosion cracking pascc is a type of intergranular stress corrosion that affects sensitized stainless steels in refineries processing feedstocks containing sulphur. However, many dss grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides and sulfidecontaining. Chloride stress corrosion cracking in austenitic stainless steel. Results of corrosion rates and rest potential measurements are shown in fig. Austenitic stainless steel may be susceptible to chloride stress corrosion cracking cscc. Chloride stress corrosion cracking the greatest corrosion advantage for duplex stainless steels is their improved resistance to cscc when compared to the austenitic grades.
It can lead to unexpected sudden failure of normally ductile metal alloys subjected to a tensile stress, especially at elevated temperature. The most common type of stress corrosion cracking in stainless steels occurs in chloride environments, which will be the focus of this discussion. Stress corrosion cracking scc behavior of 2205 duplex stainless steel dss in h. The most common environmental exposure condition responsible for scc of stainless steels is the presence of chlorides. Stress corrosion cracking an overview sciencedirect topics. This damage mechanism primarily affects standard and high carbon stainless steels, but low carbon and chemically stabilized stainless steels may also be vulnerable under certain. However, many dss grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides. Although no stainless steel grade is totally immune. Corrosion and stress corroson cracking scc susceptibility of duplex stainless steels dss depend on alloy composition, microstructure and temperature. Stress corrosion cracking of duplex stainless steel scc stress corrosion cracking is a form of corrosion which occurs with a particular combination of factors. Astm g123 002015 standard test method for evaluating. Stress corrosion cracking of a duplex stainless steel. G36 practice for evaluating stress corrosion cracking resistance of metals and alloys in a boiling magnesium chloride solution.
This mode of attack is termed stress corrosion cracking scc. For less demanding environments, duplex steels can be used. However, under certain conditions mostly involving chloridecontaining fluids and elevated temperatures even duplex stainless steels are vulnerable to this type of corrosion. Investigation of the sulfide stress cracking and stress. Stress corrosion cracking occurs at the metal surface in the form of pitting corrosion, which is the result of iron sulfide fes deposits on the metal surface. Duplex stainless steel 2205 alloy offers extensive resistance to the local corrosion factors like intergranular, pitting and crevice corrosion. Effect of alloy composition on stress corrosion cracking. For good resistance to h 2 sinduced stress corrosion cracking scc an alloy with high nickel content is recommended, and for most sour environments this type of alloy is now used. The advantage of a duplex structure is that it combines the favorable qualities of a ferritic alloy stress corrosion cracking resistance and high strength with those of an austenitic alloy ease of fabrication and corrosion resistance. The impact of scc on a material usually falls between dry cracking and the fatigue threshold of that material. Abstract duplex stainless steel dss has become an increasingly popular alternative to austenitic stainless steel for oil and gas applications due to its superior corrosion and cracking resistance as well as higher mechanical strength. Chloride stress corrosion cracking in austenitic stainless. The cpt of duplex stainless steel 2205 alloy is minimum 35oc.
The stress corrosion cracking susceptibility of duplex stainless steel din w. Stress corrosion cracking facts and how to reduce the. Aug 01, 2019 hydrogeninduced stress cracking of swaged super duplex stainless steel subsea components, corrosion 757. Stress corrosion cracking scc is the growth of crack formation in a corrosive environment. Threshold temperature for stress corrosion cracking of. This microstructure ensures that ss2205 is much more resistant to stress corrosion cracking than s304 or ss316l. Stress corrosion cracking international institute of. Duplex stainless steels dss with roughly equal amount of austenite and ferrite phases are being used in industries such as petrochemical, nuclear, pulp and paper mills, desalination plants, marine environments, and others. This damage mechanism primarily affects standard and high carbon stainless steels, but low carbon and chemically stabilized stainless steels may also be. G16 guide for applying statistics to analysis of corrosion data.
Duplex stainless steels, austenitic stainless steels with a high nickel content. After corrosion problems, column was rebuilt using duplex stainless steel but stress corrosion cracking occurred after a few years. Chloride stress corrosion cracking of a super duplex. The environmental factors that increase the cracking susceptibility include higher temperatures, increased chloride content, lower ph, and higher levels of tensile stress. They are designed to provide better corrosion resistance, particularly chloride stress corrosion and. Super duplex 2507 stainless steel uns s32750 and uns s32760. A sandvik grade with very good resistance to this form of stress corrosion cracking is sanicro 28. They are being offered by all the major stainless steel mills for a number of reasons. Feb 28, 2018 duplex stainless steel has become more popular for its combination of strength and affordability. Scc is highly chemically specific in that certain alloys are likely to undergo scc only when exposed to a small number of chemical environments. Efc publication 17, 2nd edition, corrosion resistant alloys for oil and gas production.
The higher s chromium, molybdenum and nitrogen contents give ss2205 significantly improved. High residual or applied stress, temperature above 6571c 150160f and chlorides increase the. Cscc can attack highly resistant austenitic stainless steel. Stress corrosion cracking of titanium preliminary report on. However, duplex stainless steel can still be susceptible to stress corrosion cracking in h2scontaining environments, if the environmental conditions are aggressive enough. Assessment of stress corrosion cracking resistance of activated. The chlorideinduced stress corrosion cracking scc resistance of nitrogenalloyed, powder metallurgically pm produced and hot isostatically pressed hip duplex stainless steels dss was investigated and compared to the scc resistance of two commercial wrought forged dss. Vargas pm, wastberg s and woollin p, stress based design guidelines for hydrogen induced stress cracking hisc avoidance in duplex materials, proc conf omae 200979504. Excellent resistance to stress corrosion cracking in both chloride and sour environments. It requires a susceptible material and, depending on the material, sufficient levels of. 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. Two cases of chloride stress corrosion cracking clscc of type 2205 duplex stainless steel uns s31803 tubing on a crude tower, and one. Stress corrosion cracking of duplex stainless steels in caustic. Duplex stainless steels are far less prone to this type of corrosion.
Stress corrosion cracking scc of uns s31603 austenitic stainless steel ass, uns s32205 duplex stainless steel dss and uns s32750 super duplex stainless steel sdss was investigated. Duplex stainless steel is widely used in the oil and gas industry due to its inherent resistance to localised corrosion and stress corrosion cracking. Mar 30, 2020 nbk, a specialty manufacturer of mechanical components, has introduced a ferritictype stainless steel that is resistant to stress corrosion cracking. The duplex stainless steel with their dual austeniteferrite microstructures has a resistance that is in between that of the austenite and ferrite grades. Investigation of stress corrosion cracking of austenitic. Stress corrosion cracking in duplex stainless steel. The limits for ldx 2101 duplex stainless steel application in h 2 scontaining environments the susceptibility to scc of ldx 2101 duplex stainless steel in the presence of cl. Excellent corrosion resistance in mineral acids such as hydrochloric and sulfuric acids. Stress corrosion cracking the international institute of. Stress corrosion cracking behaviour of lean duplex stainless. Chloride stress corrosion involves selective attack of a metal along its grain boundaries.
Stress strain plots for the two types of nickelresist cast irons 6. Chlorideinduced stress corrosion cracking of powder. Grades with high resistance to chlorideinduced stress corrosion cracking scc. In this study the effect of sulfide containing caustic environment and material properties dss composition and microstructure on the corrosion and scc of dss in pulping liquors synthetic white liquor was evaluated. The stress corrosion cracking behavior of duplex stainless steel dss weld joint largely depends on the ferriteaustenite phase microstructure. Stress corrosion cracking scc the standard austenitic steels astm tp304l and astm tp316l are prone to stress corrosion cracking scc in chloridebearing solutions at temperatures above 60c 140f. The resistance of two commercial duplex stainless steels to sulphide stress corrosion cracking in sour environments has been assessed by means of slow straining in a variety of solutions saturated with hydrogen sulphide over the temperature range from 2 to 95c. Stress corrosion cracking of a duplex stainless steel onepetro. Stress cracking of duplex stainless steel in refining. Know the limits of duplex stainless steels chemical.
Polarization curves on titanium oxide surfaces and kinetic data for oxidation of newly formed titanium alloy surface were also obtained. Normally 50 deg c but can occur at lower temperatures around 25 deg c in specific environments, notably swimming pools. Duplex structure of 2507 provides excellent resistance to chloride stress corrosion cracking scc. When stainless steels are fully immersed, it is rare to see chloride stress corrosion cracking at temperatures below 60 c 150 f. The required tensile stresses may be in the form of directly applied stresses or in the form of residual. Stress corrosion cracking of 2205 duplex stainless steel. Stress corrosion cracking of duplex and super duplex. Stress corrosion cracking of ldx 2101 duplex stainless steel. These are called duplex or austeniticferritic grades because their metallurgical structure consists of two phases, austenite facecentered cubic lattice and ferrite body centered cubic lattice in roughly equal proportions. Stress corrosion cracking of ldx 2101 duplex stainless steel in chloride solutions in the presence of thiosulphate author links open overlay panel f. Traditional austenitic steels are found to be more susceptible to such attack however duplex grades are less prone to it.
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