This method was also adopted in the development of an improved scc resistant type 304 steel. This paper presents the influence of h 2so 4 and nacl concentrations on the corrosion mode of aisi 304 stainless steel in h 2so 4nacl aqueous solutions. In this case, however, the alloy was reported to be resistant to scc in the nacl brine service environment. In this study, the role of material and environmental parameters on corrosion and stress corrosion cracking of duplex stainless steels in caustic solutions were investigated. Immersion test was conducted at room temperature using ubend specimens. This mode of attack is termed stress corrosion cracking scc. It becomes increasingly more corrosive with increasing temperature and concentration. The results obtained from slow strain rate and constant load tests, the polarization curves, the rapid tensile straining tests and the fractographic investigation of the fracture surface by scanning electron microscopy, permit the examination of the nature.
Their morphology and crystal orientation were analyzed. External chloride stress corrosion cracking ecscc of insulated austenitic stainless steels e. However, the ferrite transformed from the austenite by cold working decreases significantly the sensitivity of stainless steel to the stresscorrosion cracking in the both solutions. These are typical of stress corrosion cracking scc in austenitic stainless steel. Effect of alloying elements on stress corrosion cracking. Behaviour of stress corrosion cracking of austenitic. Singh raman 1, and wai hoong siew 2 1 department of mechanical and aerospace engineering, monash university, melbourne, victoria 3800, australia 2 mechanical engineer, ibm australia 60 city road melbourne, victoria 3006 australia. Deterioration by clscc can lead to failures that have the potential to release stored energy andor hazardous substances. Corrosion rate and hydrogen content in steel are also measured to study the mechanism of stress cracking resistance of martensitic stainless steels. Effect of cold working on stresscorrosion cracking of. This paper presents the influence of h2so4 and nacl concentrations on the corrosion mode of aisi 304 stainless steel in h2so4nacl aqueous solutions. The straightchromium ferritic stainless steels, twophase ferriticaustenitic stainless steels and highnickel solid solutions like alloys 800 and 600 investigated are all fully resistant to stress corrosion cracking at stress intensity k1 levels. Tsujikawa, s professor and associate professor, university of tokyo, tokyo, shinohara, t professor and associate professor, university of tokyo, tokyo.
High performance stainless steels nickel institute. The influences of thermal treatment heat affected zone cases, composition, and microstructure on corrosion are given good coverage. It occurs in austenitic stainless steel under tensile stress in the presence of oxygen, chloride ions and high temperature. In the hydroiodic acid at temperatures exceeding 177oc, alloy b2 was sensitive to transgranular stress corrosion cracking.
Stress corrosion cracking of 316 austenitic stainless steels in 3. Aqueous solutions with low concentrations of chlorides normally do not present any problems to the use of stainless steels. Supermartensitic stainless steels smss, including both lean grades without molybdenum and high grades with 2% molybdenum, have shown sensitivity to intergranular corrosion or stress corrosion cracking igscc in weld hazs during laboratory testing in chloride solutions acidified with co 2. This article describes the susceptibility of 316l stainless steel to stress corrosion cracking scc in a nitritecontaining chloride solution. The 430 steel is immune to scc in this environment, and 410 exhibits scc only when heat treated to strength levels above a critical value that depends on test temperature. The stress corrosion cracking of an austenitic stainless. Spotwelded specimen maintained above the crevicerepassivation potential to evaluate stress corrosion cracking susceptibility of stainless steels in nacl solutions.
Stress corrosion cracking susceptibility of 304l substrate. Addition of nitrite to the chloride solution, which is reported to have inhibitive influence on corrosion of stainless. The decay heat of the spent nuclear fuel in dry storage, by design, will dissipate through. Effect of ph and chloride contents on stress corrosion.
Stainless steels are damaged by stress corrosion cracking in conditions containing chlorides at the high temperatures. Quasicleavage facets have been detected in the stress corrosion cracking fracture of type 304 and type 316 austenitic stainless steels under an environment containing chloride. 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. Stress corrosion cracking behavior of nickel base alloys. Stress corrosion cracking of stainless steel the example shown indicates many intersecting, branched cracks with a transgranular propagation mode. Stress corrosion cracking of an austenitic stainless steel. It can lead to unexpected sudden failure of normally ductile metal alloys subjected to a tensile stress, especially at elevated temperature. When sulfides are present in caustic solutions the scc has been reported to occur at lower temperatures. S university of cambridge, cambridge abstract the stresscorrosion cracking of 188 type steels in hot concentrated magnesium chloride solutions has been studied. Crystal orientation analysis on stress corrosion cracking. The combination of tensile stress and a specific corrosive environment can crack stainless steels.
Cottisstress corrosion cracking of duplex stainless steel weldments in sour. Chloride stress corrosion cracking cscc is a type of intergranular corrosion. The stress corrosion cracking scc susceptibility of duplex stainless steel tubulars in oxidantfree naclh 2 s solutions simulating downhole sour gas well environments has been evaluated. Localized corrosion and stress corrosion cracking of stainless steels. The specimens in annealed and sensitized conditions were immersed in aqueous solutions containing h2so4 concentration in the range of 0 to 3. Grassistress corrosion cracking of % cr martensitic steels in sodium chloride solutions in the presence of. Thierry, lowtemperature stress corrosion cracking of stainless steels in the atmosphere in the presence of chloride deposits, corrosion 65, 105. The most common environmental exposure condition responsible for scc of stainless steels is the presence of chlorides. Stress corrosion cracking of stainless steels in naci solutions markus o. Traditional austenitic steels are found to be more susceptible to such attack however duplex grades are less prone to it.
There can be a risk of stress corrosion cracking scc attack at higher temperatures. However, when sulfides are present in caustic solutions the scc of austenitic stainless steels has been reported to occur at lower temperatures. Behaviour of stress corrosion cracking of austenitic stainless. Influence of high temperature on corrosion behavior of 304. The straight chromium ferritic stainless steels, twophase ferriticaustenitic stainless steels and high nickel solid solutions like alloys 800 and 600 investigated. Behaviour of stress corrosion cracking of austenitic stainless steels in. Stress corrosion cracking international institute of. Effect of strength on stress cracking resistance of martensitic stainless steels whose yield strengths of 805ksi are studied. Pdf stress corrosion cracking of austenitic stainless steel in. Selection of stainless steels for handling sodium hydroxide naoh sodium hydroxide caustic soda is a strong base, used widely for cleaning metals. Chloride stress corrosion cracking ssina specialty steel.
Chloride stress corrosion cracking in austenitic stainless. Intergranular stress corrosion cracking of welded steel twi. Research using solutions of chemically pure caustic sodium hydroxide naoh led to the development of a diagram that attempts to delineate the param eters of concentration and tem perature governing stress corrosion cracking scc of type 300 series austenitic stainless steels ss, such as. Longtime stress corrosion cracking tests were made in boiling, 45% magnesium chloride mgclsub 2 solution at 155 c and in an autoclave, 26% sodium chloride nacl solution at 200 c on 15 commercial stainless steel and nibased alloys and four laboratory fecrni heats. Stress corrosion cracking of cuzn and cua1 alloys in cuprous ammonia solutions can only occur when the parting limits for dealloying are exceeded. As potential is decreased, eventually, the salt film is. A spotwelded specimen with both a crevice and residual stresses was immersed in the nacl solutions, and kept potentiostatically for 72 hours at a potential slightly above the crevice repassivation potential with no additional applied stress. Postweld heat treatment to avoid stress corrosion cracking. Stress corrosion cracking scc is the growth of crack formation in a corrosive environment. Other environmental factors, like ph of the solution, temperature, and resulting electrochemical potential also influence the scc susceptibility of duplex stainless steels. The metallurgical influences on the stress corrosion resistance of many commercial stainless steels have been studied using the fracture mechanics approach.
Stress corrosion cracking susceptibility of duplex. Stress corrosion cracking of 304l stainless steel in. The resistance of austenitic stainless steels to scc is related to the nickel content of the steel. All three families of the highperformance stainless steels will deliver a wide range of resistance to chloride pitting and stress corrosion cracking superior to that of types 304 and 316. Several chapters are spent on those special forms of corrosion that are investigated in the great detail in stainless steels, namely, pitting corrosion, crevice corrosion, and stress corrosion cracking. The stress corrosion cracking of austenitic stainless. Corrosion by caustic sodium or potassium hydroxide at all concentrations is easily handled at room temperature with a variety of metals and alloys, including carbon steels. Stress corrosion cracking scc of austenitic stainless steels of types 316 was. The straightchromium ferritic stainless steels, twophase ferriticaustenitic stainless. Paper presented at stainless steel world 2005 conference, maastricht, the netherlands, 810 november 2005. Modern highstrength stainless steels offer combined mechanical and corrosion resistance, but are susceptible to environmental cracking in. Stainless steels types 304 and 316 can be considered resistant below 80 degc, up to the limit of solubility. Scc is highly chemically specific in that certain alloys are likely to undergo scc only when exposed to a small number of chemical environments. Speidel the metallurgical influences on the stress corrosion resistance of many commercial.
A great concern for the longterm integrity of canisters located near the coastline is chlorideinduced stress corrosion cracking of austenitic stainless steels 3,4,5. The alloys tested had compositions of 21 to 25 pet cr. Influence of high temperature on corrosion behavior of 304 stainless steel in chloride solutions aip advances 6, 115301 2016. Stress corrosion cracking of duplex stainless steels in. The main drawbacks of stainless steels is that these alloys are sensitive to chloride induced localized attack like pitting and crevice attack and stress corrosion cracking. Stress corrosion of ferritic and martensitic stainless. Stress corrosion cracking of an austenitic stainless steel in nitritecontaining chloride solutions r. Stress corrosion cracking of stainless steels in nacl. Pdf stress corrosion cracking of an austenitic stainless steel in. Influences of h2so4 and nacl concentrations on stress. However, localised evaporation of dilute chloride solution can increase the chloride concentration and lead to pitting corrosion, or even stress corrosion cracking scc under.
In both steels the coldworked material cw showed higher crack propagation rate than annealed one st, where the variation of the propagated crystal planes of. Though cracks were not producedduring the first stage of the first. Chloride stress corrosion cracking in austenitic stainless steel chloride stress corrosion cracking clscc is one of the most common reasons why austenitic stainless steel pipework and vessels deteriorate in the chemical processing and petrochemical industries. The interaction of corrosion fatigue and stresscorrosion.