Thiosulfate Corrosion in Paper-Machine White Water

Garner, A.

doi:10.5006/1.3582988

Cited by 53 publications

(22 citation statements)

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“…5 Localized corrosion of SS in S 2 O 3 2--containing environments has been studied extensively. [6][7][8][9][10][11][12][13][14][15][16][17] Thiosulfate pitting is known to occur in a limited potential range 6 and molar ratio ([Cl -] + sulfate [SO 4 2-])/[S 2 O 3 2-]. 7 The most sensitive potential range for thiosulfate pitting is at 0 mV vs saturated calomel electrode (SCE) to -400 mV SCE 8 and at molar ratio 10 to 30.…”

Section: Introductionmentioning

confidence: 98%

“…Sensitized UNS S30403 was prone especially to pitting at SO 4 2-/S 2 O 3 2molar ratios from 6 to 23 (100 mg/L SO 4 2-, pH 4.5, 50°C, 5 mg/L to 20 mg/L S 2 O 3 2-) at potentials from 0 mV SCE to -300 mV SCE , while unsensitized UNS S30403 experienced thiosulfate pitting at higher potential levels, 100 mV SCE to -100 mV SCE . 8 In the absence of Cl -, other anions like SO 4 2-, may form hydrolyzed metal compounds and maintain or increase acidity inside the pit.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of Stainless Steels in Simulated Paper Machine Environments

Laitinen

1999

CORROSION

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The localized corrosion behavior of austenitic stainless steels (SS) UNS S30403 and UNS S31603, and duplex SS UNSS31803 was compared in simulated paper machine environments containing chloride, sulfate, and thiosulfate at pH 3 and 65°C. Electrochemical testing of the materials was performed by cyclic polarization scans and scratch tests. Thiosulfate caused a remarkable decrease in repassivation potentials (E pp ) and a slight decrease in pitting potentials (E np ) of UNS S30403 and UNS S31603, when compared to the corresponding E pp and E np values determined in similar solutions without thiosulfate addition. Pits on UNS S30403 and UNS S31603 steels were enriched in Cr and Cu and depleted in Fe when compared to the base metal. Thiosulfate being present in the solution pits contained also very high amounts of S. Thiosulfate was proposed to be reduced to hydrogen sulfide (H 2 S) inside the pits enhancing the anodic dissolution process of SS. In the case of UNS S31803, test environments had hardly any influence on the determined high E pp and E np values. Chloride concentration had to be a minimum of 500 mg/L until any localized corrosion could be observed on UNS S31803.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Comparison of Stainless Steels in Simulated Paper Machine Environments

Laitinen

1999

CORROSION

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“…Thiosulfate increases the possible potential range of corrosion pits to grow by lowering the repassivation potential. Hydrogen sulfide originating from thiosulfate is proposed to accelerate the anodic dissolution inside corrosion pits and crevices by forming sparingly soluble metal sulfides and by acidifying the local environment [Garner (1985)]. …”

Section: Fig 4 Optical Microscopic Photographs Of Pits Formed On 304mentioning

confidence: 99%

“…It is suggested that these cracks can be formed due to the work hardening that can transform a part of the austenite phase to the martensite during the fatigue test. The martensite phase is considered a hard phase and fractured in a brittle manner and sometimes causes micro-cracks inside the metal [Garner (1985)]. …”

Section: Fatigue Behavior Of Ss 304mentioning

confidence: 99%

The Effect of Pitting Corrosion on the Fatigue Strength of 304 and 316 Stainless Steel Alloys

Al-Taher¹,

Ghayad²,

Ibrahim³

et al. 2014

Journal of Metallurgical Engineering

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Pitting corrosion behavior of 304 and 316 stainless steel alloys was investigated in 3.5% NaCl solution containing 100 ppm thiosulfate ion as pitting corrosion initiator. Experiments were performed using potentiodynamic polarization and potentiostatic techniques at room temperature. The shape, size, and pit depth of the formed corrosion pits were also determined using the metallurgical light microscope. The fatigue strength of the pitted samples (either single or multipitted) was determined using plain-bending fatigue test machine. The fracture surface was also investigated using scanning electron microscope (SEM).The results show that SS 304 is more susceptible to pitting corrosion and has lower fatigue strength than SS 316 for the unpitted alloys samples. For both alloys, the single pitted samples shows that a deterioration percentage in fatigue is of about 15% while the multi pitted samples shows a deterioration percentage in fatigue of about 33% compared to the unpitted samples. The crack through the specimen surface was noticed to be initiated from the pit and propagates in two perpendicular sides to each other.

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“…0ϭٌ· Jϭٌ· (Ϫsٌf) ииииииииииииииииииииииииииииииииииииииииииии( 3 ) 13) J c иииииииииииииииииииииииииииииииии ( 6 ) f 0,steel ϭϪ0.059 log(gm NaCl )Ϫ0.5105 ииииииииииииииииииииииииии ( 7 ) f 0,zinc ϭϪ0.059 log(gm NaCl )Ϫ1.0242 ииииииииииииииииииииииииии( 8 )…”

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Numerical Analysis Model of Galvanic Corrosion with Ion Movement and Reactions

Okada¹,

Matsumoto²,

Nishihara³

et al. 2009

Tetsu-to-Hagane

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Synopsis : Numerical analysis models for galvanic corrosion has been developed in recent years, but most of the ordinary models only can calculate current density and potential distribution in an electrolyte solution. In order to make clear corrosion mechanism, more information such as pH, ion and corrosion product distributions are necessary. However, it is difficult to compute these phenomena by mathematical model because various kinds of ions and complex reactions exist in corrosion progress. Calculating ion movement with satisfying charge conservation is especially difficult.We have developed a new numerical analysis model for galvanic corrosion that can calculate ions movement and reactions. In this model, ion density distribution is corrected by solving Poisson's equation to satisfy charge conservation. Equilibrium reactions are computed after calculating ion transportation.Galvanic corrosion of a model Zn/steel couple in a NaCl solution was calculated with this model. The difference of ion and corrosion product distribution in 50 ppm and 50000 ppm NaCl solutions was discussed. Corrosion product distribution obtained by this numerical analysis model was well agreed with OH Ϫ distribution on a galvanic corrosion specimen measured by FT-IR method qualitatively.

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Thiosulfate Corrosion in Paper-Machine White Water

Cited by 53 publications

References 0 publications

Comparison of Stainless Steels in Simulated Paper Machine Environments

Comparison of Stainless Steels in Simulated Paper Machine Environments

The Effect of Pitting Corrosion on the Fatigue Strength of 304 and 316 Stainless Steel Alloys

Numerical Analysis Model of Galvanic Corrosion with Ion Movement and Reactions

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