The observed crack propaga tion is the result of the combined and synergistic interaction of mechanical stress and corrosion re actions. After addition urotropine, the uniform corrosion was inhibited, and the scc sensitivity of super cr steel. Abstract controlling parameters for intergranular stress corrosion cracking scc of line pipe steels exposed to concentrated carbonatebicarbonate solutions are reasonably well understood. Assessment of the stress corrosion cracking in a chloride. Influence of material and processing on stress corrosion. Durability aspects of arglassreinforcement in textile reinforced concrete, part 2. From observations of the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking scc in carbon steels, and from the form of potentiodynamic polarization curves and the structural dependence of the corrosive attack, it was predicted that carbonate solutions would also produce intergranular stress corrosion in carbon steels. Failure of prestressing steel induced by crevice corrosion. The results indicated that the super cr stainless steel was susceptible to uniform and stress corrosion cracking scc without inhibitors.
Effects of hydrogen assisted stress corrosion on damage. Stress corrosion cracking and corrosion susceptibility of. Stress corrosion cracking mechanism of prestressing steels in bicarbonate solutions article in corrosion science 4911. The impact of local concrete crack on the prestressed steel stress corrosion sensitivity is studied with the ssrt, sem and other methods. Laboratorybased investigation into stress corrosion.
Stress corrosion is the crystalline cracking of metals under tensile stresses in the presence of corrosive agents. Scc in pipelines is a type of environmentally assisted cracking. Galvele, jr 1995 electrochemical aspects of stress corrosion cracking, in. This investigation screened for potential scc development three candidate high strength alloys for use as. Stress corrosion cracking mechanism of prestressing steels in bicarbonate solutions. Stress corrosion cracking mechanism of prestressing steels.
Scc occurs as a result of a combination between corrosion and tensile stress. The impact on bridge reliability, of prestressing steel deterioration and tendon rupture created by corrosion mechanisms, is much more critical and rapid than that of any other component of a prestressed concrete bridge. Previously, we present some results about stress corrosion cracking, crack propagation rate or, even, crack arrest conditions in high strength steels. Scc occurs due to the progressive development and growth of cracks in the surface of a metal, and it is caused by the combined effects of stress and a corrosive environment affecting susceptible metals and alloys. The conditions for stress corrosion to occur are that the steel is subjected to tensile stresses arising from external loading or in. This process has not been fully elucidated and several theories exists in order to explain the cases in. Prestressing steels occasionally fail by a process named stress corrosion cracking. Experimental and statistical analysis of the corrosion in.
Advances in construction materials 2007 book, 2007. The overall reason to prestress steel is that it raises both the quality and the resistance to tension and compression characteristics of the steel although apparently recent, prestressed steel is a material whose origins date back a long way. Stainless steel reinforcing has an elevated chloride threshold and is an attractive alternative for prestressed concrete applications. Their geometry is such that if they grow to appropriate lengths they may reach a critical size that results in a transition from the relatively slow crack growth rates associated with stress corrosion to. However, due to the high strength requirements for prestressing strands, concern exists about the possibility of stress corrosion cracking scc. Sce were investigated by slow strain rate tensile ssrt test. The electrochemical behaviour of prestressed steel rods in carbonate and bicarbonate solutions was widely studied in. Stresscorrosion cracking scc is a term used to describe service failures in engineering materials that occur by slow, environmentally induced crack propagation. Studies on behaviour of prestressing steel cold drawn eutectoid steel in nahco3 solution, simulating carbonated concrete, was carried out by alonsoet al. Susceptibility of prestressing steel to corrosion in prestressed and posttensioned concrete structures is covered. At 175 oc the active corrosion rate of carbon steel exceeded 10 mmy 400 mpy. Corrosion of prestressing steels reapproved 2010 reflects the current understanding of corrosion of prestressing steels in concrete. Cablebolt failures due to stress corrosion cracking scc could significantly compromise the sustainability and longterm stability of underground constructions. Increasing temperature was found to accelerate the corrosion rate of csteels in flash tank liquors.
Technical report 44 pages, isbn 9782883940666, october 2003 pdf format. Carbonate stress corrosion cracking acscc is a common problem in the oil and gas production, petroleum refining, and petrochemicalchemical processing industries. A study on the mechanism of stress corrosion cracking of. The result shows that, the local concrete crack will increase the prestressed steel stress corrosion sensitivity. As consequence, two technological testing procedures, fip. Carbonate stress corrosion cracking acscc inspectioneering. This process has not been fully elucidated and several theories exists in order to explain the cases in which real structures have collapsed. A particular case of corrosion of the steel embedded in concrete is the stress corrosion cracking scc, which can appear in prestressed structures. Acscc is a form of alkaline stress corrosion cracking that often occurs more aggressively at higher ph and high concentrations of carbonate solutions. The formation of stress corrosion microcracks on the metal surface below the crevice is based on two mechanisms. To evaluate if concrete carbonation can promote this kind of failure, constant load tests in bicarbonate aqueous solutions under anodic polarization were carried out on high strength steel wires. Scc results from the formation of cracks due to various factors in combination with the environment surrounding the pipeline that together. Thorough understanding of scc mechanisms of dss in chloride and hydrogen sulfidecontaining solutions has been useful for material selection in many. Stress corrosion cracking of highstrength steels abstract.
Impact of local concrete crack on the prestressed steel. The adoption of the technique of pre stressing is attributed to paxton, who in 1851 utilised this technique for the realisation of the crystal palace. Stress corrosion cracking scc is a type of environmentallyassisted cracking eac, or the formation of cracks caused by various factors combined with the environment surrounding the pipeline. The pit to crack transition has been studied by some authors turnbull et al. Corrosion of prestressed reinforcing steel in concrete. Failure mechanisms of high strength steels in bicarbonate. In the case of presstressed structures corrosion can induce stress corrosion cracking sanchez et al. Investigation of stress corrosion cracking susceptibility. Fracture mechanicsbased testing was used to quantify the stresscorrosion cracking and corrosion fatigue behavior of a precipitationhardened martensitic stainless steel custom 465h950 in. The use of dss has been restricted in some cases because of stress corrosion cracking scc, which can initiate and grow in either the ferrite or austenite phase depending on the environment. This process has not been fully elucidated and several theories exists in order to. The conditions for stress corrosion to occur are that the steel is subjected to tensile stresses arising from external loading or internally induced stress e. Durability aspects of arglassreinforcement in textile reinforced concrete, part 1. Moreover, these steels undergo to brittle fracture as a consequence of stress corrosion cracking phenomena.
Inhibition effect of some inhibitors on super cr steel. The report includes chapters that cover the various types of prestressing steel, including some discussion on metallurgical differences. Alonso c, procter r p m, andrade c and maria m s d 1993 susceptibility to stress corrosion cracking of a prestressing steel in nahco 3 solutions corros. What causes stress corrosion cracking in pipelines.
Susceptibilities to stress corrosion cracking scc of x80 pipeline steel in high ph solutions with various concentrations of hco 3. Whereas some of the methods discussed for conventional reinforcedconcrete bridges are applicable to prestressed concrete components e. At 145oc the active corrosion rate of carbon steel was less than 2 mmy 80 mpy. Corrosion and prestressed concrete bridges structures. Protection systems consisting of mechanical or electrochemical barriers to the aggressive media are available, but experience shows that they are doubtfully effective, if not counterproductive 81. Fernandez, joseph rogelio, stress corrosion cracking evaluation of candidate high strength stainless steels for prestressed concrete 2011. Stress corrosion cracking of carbon steel in hot potassium. This paper summarizes the results of an investigation of the stress corrosion cracking scc behavior of carbon steel in carbonatebicarbonate solutions encountered in hot carbonate acid gas scrubbing processes for co2 removal.
Surface mobility mechanism of stress corrosion cracking, corros. Corrosion is the principal reason of durability reduction of reinforced concrete structures andrade et al. This report covers various types of prestressing steel, including some discussion on metallurgical differences, and supplements information presented in aci 222r to include topics specifically related to prestressing steels. Influence of material and processing on stress corrosion cracking of prestressing steel case studies. Types of corrosion and recent theories explaining stress corrosion and hydrogen embrittlement are presented. The inhibition effect of some inhibitors on super cr stainless steel corrosion in cacl 2 completion fluids with 1. One of the causes of such failures was identified to be stress corrosion cracking scc. The role of residual stresses in the performance and durability of prestressing steel wires. Corrosion is related to the susceptibility of the material to the environment, while stresses may be residual, external or. Carbonatebicarbonate solutions stainless steels acidic chloride solutions naclh2o2 solutions seawater h2s naohh2s solutions.
Stress corrosion cracks propagate over a range of velocities from about 103 to 10 mmh, depending upon the combination of alloy and environment involved. Deterioration mechanisms are discussed, including hydrogen embrittlement and stresscorrosion cracking. To fully understand the scc of cable bolts, a twostep methodology was implemented. This paper outlines the mechanism of stress corrosion cracking scc and how it can cause premature failure of rock bolts. The scc is produced by the simultaneous action or synergy of a mechanical tension and a corrosive medium. Sridhar ramamurthy and andrej atrens stress corrosion. Stress corrosion cracking characteristics of a range of. Stress corrosion cracking evaluation of candidate high. Present paper deals with the approach to the understanding of scc mechanism of construction prestressing steel occurring in a simulated carbonated media and under the effect. Failure mechanisms of high strength steels in bicarbonate solutions under anodic polarization. Factors such as concrete materials, prestressing steel, and environments, which may influence such corrosion, are. The interaction of corrosion fatigue and stresscorrosion.
Stress corrosion cracking of carbon steel in carbonate. Influence of material and processing on stress corrosion cracking of prestressing steel case studies category. Hydrogen embrittlement stress cracking in prestressing steel wires surya kumar singh, paulette s. What is stress corrosion cracking and why does it occur.
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