Stress corrosion cracking in stainless steel 304 properties

Stainless steel is the name of a family of ironbased alloys known for their corrosion and heat resistance. Corrosion and corrosion properties of stainless steels. Tensile and stress corrosion cracking properties of type 304 stainless steel irradiated to a very high dose author links open overlay panel h. In recent years, failures of reactor internal components have been observed after the components have reached neutron fluence levels 5 x 10 20 ncm2 e 1 mev. Aisi 304 grade stainless steel uns s30400 aisi 304 stainless steel uns s30400 is the most commonly used material in stainless steels, and is usually purchased in an annealed or cold worked state. Prior cold deformation of the structure under load increases the risk of stress corrosion cracking. Although most failed components can be repaired or replaced, such operations are difficult and very expensive. Stainless steel 304 has good resistance to oxidation in intermittent service up to 870c and in continuous service to 925c. Because ss 304 contains 18% chromium cr and 8% nickel ni, its also known as 188 stainless steel. As neutron fluence increases, austenitic stainless steel ss core internals of boiling and pressurized water reactors bwrs and pwrs become susceptible to irradiationassisted intergranular ig cracking. Tensile and stress corrosion cracking properties of type.

Stress corrosion also called stress corrosion cracking or chloride stress corrosion. Transgranular, intergranular, and granulated stress corrosion cracks were observed. Localized corrosion and stress corrosion cracking of stainless steels. Corrosion resistance properties in stainless steels. Normally 50 deg c but can occur at lower temperatures around 25 deg c in specific environments, notably swimming pools. Aisi sae astm 304 stainless steel cant be hardened by heat treatment but can be hardened by cold working. The type of cracking observed was a function of the degree to which the specimens were sensitized. Ricker, national institute of standards and technology stress corrosion cracking scc is a term used to describe service failures in engineering materials that occur by slow, environmentally induced crack propagation. The elbow was welded with two straight pipes at two ends. Scc normally initiates at the triple junction of the grain boundaries and then propagates directly along the grain boundary to another junction where the propagation is arrested. The earliest incidents of irradiation assisted stress corrosion cracking iascc in bwrs occurred during the early 1960s and were associated with cracking of type 304 stainless steel fuel cladding, where the driving forces for cracking were the increasing tensile hoop stress in the cladding due to the swelling fuel and the highly oxidizing. Stress corrosion cracking can occur at temperatures over 60c. It is subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above 60 c approximate.

Pitting and crevice corrosion can occur in environments containing chlorides. Type 304 stainless steel stress corrosion cracking scc in stainless steels. Irradiationinduced stress corrosion cracking of austenitic stainless steels. Stress corrosion cracking of sensitized stainless steel type 304 in. Effects of temperature and pressure on stress corrosion. Mar 11, 2020 this research was focused on the failure analysis of a cracked ss304 stainless steel elbow from a chemical plant. Stress corrosion cracking susceptibility of 304l substrate. Pdf stress corrosion cracking of austenitic stainless.

It has excellent forming and welding characteristics. The material used was austenitic stainless steels, type 304l with chemical composition in table i. However, continuous use at 425860c is not recommended if corrosion resistance in water is required. Pitting or crevice corrosion can occur on most stainless steel grades. It can be detrimental to austenitic stainless steels, one of the main reasons these steels are not considered a cureall for corrosion problems. The stress corrosion cracking of a sensitized type 304 stainless steel has been studied at room temperature using controlled potentials and two concentrations of sodium thiosulfate. It is concluded that stress corrosion cracking was the main reason for the cracking of the elbow. In most environments, the ppm are so small the effects on stainless are minute. Type 304 represents the largest volume followed by type 304l. Stress corrosion cracking scc is the main corrosion failure mode for 310s stainless steel. Chemical composition of type 304 and type 316 stainless steels as per astm a240. The most common environmental exposure condition responsible for scc of stainless steels is the presence of chlorides.

The general pattern of the observed failures indicates that as nuclear plants age and fluence increases, various apparently nonsensitized austenitic. Chloride stress corrosion is a type of intergranular corrosion and occurs in austenitic stainless steel under tensile stress in the presence of oxygen, chloride ions, and high temperature. The figure on the left is the normalized microstructure and the one on the right is the sensitized structure and is susceptible to intergranular corrosion or intergranular stress corrosion cracking. Grade 304 stainless steel is excellent in a wide range of atmospheric environments and many corrosive media. Stress corrosion cracking scc is one failure mode that may occurred on hot insulated austenitic stainless steel pressure vessels and piping. The composition of stainless steel alloys used in steam service does have.

The lower carbon content minimizes chromium carbide precipitation due to welding and its susceptibility to intergranular corrosion. This combination of properties is the reason for the extensive use of these alloys which represent nearly one half of the total u. This paper discuses the stress corrosion cracking observed when slow strain rate tests were run on aisi 304 stainless steel specimens in oxygenated 288 c water. Selected properties of the halides and overview of observed modes of. Chlorides can cause pitting, crevice corrosion, and stress corrosion cracking. Chlorides are probably the single biggest enemy of stainless steel. Stress corrosion cracking on an insulated austenitic. Past researched about scc of 310s primarily focus on the corrosion mechanism and influence of temperature and corrosive media, but few studies concern the. Influence of chromium depletion on intergranular stress. This research was focused on the failure analysis of a cracked ss304 stainless steel. Stress corrosion cracking of duplex stainless steel scc stress corrosion cracking is a form of corrosion which occurs with a particular combination of factors. Effects of laser peening on stress corrosion cracking scc. The resistance of austenitic stainless steels to scc is related to the nickel content of the steel. One significant concern for the structural integrity is stress corrosion cracking scc in the heat affected zone of welds in the stainless steel canister that confines the spent fuel.

Chlorideinduced stress corrosion cracking ciscc of welded heat affected zones haz is of special concern, as it is a welldocumented mode of attack for austenitic stainless steels including 304hl and 316l in marine environments, and many isfsi sites are located in coastal areas. Potential and strain rate effects in slow strain rate. Stress corrosion cracking scc is a common issue with many specialty alloys. Most notably, pitting and cracking in this instance had initiated andor.

How to reduce the risk of stress corrosion cracking scc the risk of stress corrosion cracking scc can be minimized through plant and equipment design. With regard to the safe temperature for carbon steel, the reader should look at the curve in figure 1. This paper describes some results selected from a larger program that was aimed at understanding the stress corrosion cracking scc initiation of type 304 stainless steel uns s30400 in high. Why are austenitic stainless steels more susceptible to. Anodic protection is possible only for materialenvironment combinations. The most common type of stress corrosion cracking in stainless steels occurs in chloride environments, which will be the focus of this discussion. Tensile and stress corrosion cracking properties of type 304. Pdf stress corrosion cracking of stainless steel components in. Chloride stress corrosion cracking in austenitic stainless steel. One of the main characteristics of stainless steel is its minimum chromium content of 10. May 18, 2005 type 304 is the most versatile and widely used stainless steel. Stress corrosion cracking of a 304 stainless steel elbow.

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. Although most failed components can be repaired or replaced. Pitting corrosion has been reported from household bleach spills on stainless steel 304 type sinks in domestic environments. Chlorideinduced stress corrosion cracking ciscc of welded heat affected zones haz is of special concern, as it is a welldocumented mode of attack for austenitic stainless steels including 304hl and 316l in marine environments 1, and many isfsi sites are located in coastal areas. Stress corrosion cracking scc is the growth of crack formation in a corrosive environment. Deterioration by clscc can lead to failures that have the potential to release stored energy andor hazardous substances. Stress corrosion cracking of aisi 304 and aisi 316 austenitic. The effects of coldrolling 20% thickness reduction and sensitization treatment 600c10h on the microstructure, tensile properties and susceptibility to stress corrosion cracking of 304. Therefore, standard grades such as 304304l and 316316l are very susceptible to this mode of attack. There is an additional risk of stress corrosion cracking scc at.

This mode of attack is termed stress corrosion cracking scc. The place to start uns s30400 grade 304 is the greatest stainless success story. Duplex grades are usually divided into three subgroups based on their corrosion resistance. Each alloy represents an excellent combination of corrosion resistance and fabricability. Grade 304 stainless steel is the most versatile and the most widely used of all stainless steels. Chloride stress corrosion cracking ssina specialty steel. Type 304 has good processability, weldability, corrosion resistance, heat resistance, low. Type 321 stainless steel s also advantageous for high temperature service because of its good mechanical properties. Film and ph effects in the stress corrosion cracking of. So, a stainless steel corrosion can not have all media. Transgranular, granulated, and intergranular stress. Stress corrosion cracking of sensitized type 304 stainless steel in high temperature chloride solutions l.

Detection and characterization of stresscorrosion cracking on 304 stainless steel by electrochemical noise and acoustic emission techniques author links open overlay panel g. It accounts for more than 50% of all stainless steel produced, represents between 50 and 60% of australias consumption of stainless materials and finds applications in almost every industry. The most common type of stress corrosion cracking in stainless steels occurs in chloride environments, which will. The properties, applications and fabrication details are provided for 304 stainless steel. The resistance of various commercial alloys to stress corrosion cracking scc in 50% naoh was evaluated at temperatures in the range 284 to 332 c. It has good drawability the combination of low yield strength and high elongation permits fabrication into complex shapes. Grain refinement can improve the mechanical properties and corrosion resistance of ansi 304 austenitic stainless steel. Detecting and imaging stress corrosion cracking in. Type 304 stainless steel an overview sciencedirect topics. A precursor of stress corrosion cracking in chloridebearing environments is pitting corrosion, occurring if the stainless steel is not sufficiently resistant to pitting.

Stress corrosion cracking scc three forces combine to cause this type of corrosion. In both constant extension rate and constant load tests, the crack velocities attain extremely high values, up to 8 xm s l. Corrosion properties international stainless steel forum. Influence of high temperature on corrosion behavior of 304. Stainless steel corrosion pitting corrosion crevice. The combination of tensile stress and a specific corrosive environment can crack stainless steels. This ph range is considered to be critical for stress corrosion cracking of 304 stainless steel because it is the range in which a corrosion resistant protective film is formed in the presence of the corrodent solution. 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. It is reported that ph value and electrolyte composition affect scc type. Pitting and stress corrosion cracking behavior in welded. Scc is often associated with chlorides, but can also occur with caustics and other corrosive media. Although no stainless steel grade is totally immune to chloride scc, the relative resistance of stainless. Chloride stress corrosion cracking scc of type 304 and 304l austenitic stainless.

The stress corrosion cracking scc of aisi 304 and aisi 316 austenitic stainless steels in 0. However, 304 stainless does not perform well in highsaline environments. Figure 3 shows two microstructures of type 304 stainless steel. Why are austenitic stainless steels more susceptible to chloride stress corrosion cracking than ferritic stainless steels. Stress corrosion cracking of an austenitic stainless steel. Chloride stress corrosion cracking clscc is a type of stress corrosion cracking scc and is one of the most well known forms of scc in the refining and chemical processing industries.

Brown metals company currently offers 302 304 full hard sra stainless steel in these thicknesses. Crevice corrosion can be addressed by proper design of the products by minimising of shielded areas and using stainless steel containing higher alloying elements. Type 321 stainless steel offers higher creep and stress rupture properties than type 304 and, particularly, type 304l which might also be considered for exposures where sensitization and intergranular corrosion are concerns. Stainless steels are more resistant to general corrosion compared with carbon steel. The mechanisms of corrosion include crevice corrosion, pitting corrosion, intercystalline or intergranular corrosion icc, stress corrosion cracking scc and galvanic bimetallic corrosion. However, its tendency to corrode in the presence of halide ions limits the applications. The corrosion resistance of stainless steel arises from a passive, chromiumrich, oxide film that forms naturally on the surface of the steel. Stainless steels stainless 304 properties, fabrication. Aisi 304 stainless steel is widely used in many applications because of its mechanical and corrosion properties. Their mixed microstructure provides improved resistance to chloride stress corrosion cracking in comparison to austenitic stainless steel types 304 and 316. Chloride stress corrosion cracking scc of type 304 and 304l austenitic stainless steels ss was studied by a constant load method in air at a temperature of 353 k with relative humidity rh of. Chloride induced stress corrosion cracking of type 304 and.

In 2007, badak lng experienced this problem on its amine regenerator pressure vessel where the shell are insulated and made of austenitic stainless steel grade 304l. Sensor requirements for detection and characterization of. Chloride stress corrosion cracking inspectioneering. While type 304 sensitized stainless steel suffer intergranular attack and scc in the. Chloride induced stress corrosion cracking of type 304. When the weldment is not suitable for full annealing, the residual stress of ss 304 grade stainless steel can be moderately reduced below 450 c.

Ss304 grade aisi 304 stainless steel properties, composition. The molybdenum added to 316 stainless increases the corrosion resistance to chlorides like sea water and deicing salts. Stress corrosion cracking scc in stainless steels request pdf. Stresscorrosion cracking of sensitized type 304 stainless. 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. Its chemical composition, mechanical properties, weldability and ncorrosionoxidation resistance provide the best allround performance stainless steel at relatively low cost. Stress corrosion cracking of aisi 304 and aisi 316. Stainless steels stainless 304 properties, fabrication and. Chloride stress corrosion cracking in austenitic stainless.

Minimizes stress corrosion cracking in service environments sra material is ideally suited for stencil, chemical etching, and laser etching type applications. There is an additional risk of stress corrosion cracking scc at higher temperatures. Cracks were located mainly at positions close to the weld joint and the arc where very strong tensile residual stress existed. The effect of microstructural changes in 304 austenitic stainless steel induced by the processes of gas tungsten arc welding gtaw and laserbeam welding lbw on the pitting and stress corrosion cracking scc behaviors was investigated. In these situations, 316 stainless steel is the correct choice. Stress corrosion cracking scc of duplex stainless steel. Type 304 and 304l austenitic stainless steels sss, has increased. Stress corrosion cracking of sensitized type 304 stainless. Corrosion of stainless steel by hot caustic 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. This paper presents a fusion welding process that was developed for snf canister repair. It is thought to start with chromium carbide deposits along grain boundaries that leave the metal open to corrosion. Ricker, national institute of standards and technology stresscorrosion cracking scc is a term used to describe service failures in engineering materials that occur by slow, environmentally induced crack propagation.

In some instances type 304 can be used in the aswelded condition. Next to water, chloride is the most common chemical found in nature. Pdf stress corrosion cracking of austenitic stainless steels in. Stainless steel grade 304 cs 304 304l technical data.