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oxygen pitting

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Published: 30 August 2021
Fig. 22 Schematic showing the mechanism of oxygen pitting More
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Published: 15 January 2021
Fig. 19 Oxygen pitting along the outside-diameter surface of boiler tubes from a fire-tube boiler. (a) Through-wall pitting due to oxygen pitting. (b) Oxygen pitting had penetrated approximately 80% of the boiler tube wall thickness on this sample. More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001654
EISBN: 978-1-62708-220-4
.... This was attributed to the fact that they were downstream from a deaeration unit. It was concluded that the pitting was caused by a synergistic effect of chlorine and oxygen in the make-up water. Because it was not possible to install a deaeration unit upstream of the heat exchangers, it was recommended...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c0048318
EISBN: 978-1-62708-234-1
... that water contained in the tube during shutdowns had accumulated and cumulative damage due to oxygen pitting resulted in perforation of one of the tubes. Filling the system with condensate or with treated boiler water was suggested as a corrective action. Alkalinity was suggested to be maintained at a pH...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.bldgs.c9001701
EISBN: 978-1-62708-219-8
... by oxygen concentration cells and oxygen-pitting related corrosion. Both types of corrosion are due to the poor quality of the water and the lack of corrosion control in the water system. Water chemistry Water heaters Water pipelines Water treatment ASTM A106 UNS K03006 Crevice corrosion...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c0048814
EISBN: 978-1-62708-229-7
... of the fracture to the pits on the inner surface of the vessel were revealed. Copper deposits with zinc were revealed by EDS examination of discolorations. Pitting was revealed to have been caused by poor oxygen control in the steam generators and release of chloride into the steam generators. It was concluded...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c9001696
EISBN: 978-1-62708-234-1
... that settles on exposed surfaces as they are being subjected to severe mechanical loads imparted during lift-off. Failure analyses were performed on 304 stainless steel tubing that ruptured under such conditions, while carrying various gases, including nitrogen, oxygen, and breathing air. Hydrostatic testing...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006825
EISBN: 978-1-62708-329-4
... in steam temperature from inlet to outlet of a high-temperature superheater should be uniform across the superheater, differences in inlet temperature will lead to differences in tube metal temperature. At times, uneven burner adjustments result in localized overheating. Uneven flue-gas or oxygen...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.petrol.c0048698
EISBN: 978-1-62708-228-0
.... The tee joint in the piping between the heat exchanger and the sieve bed failed after 12 months. A hole in the tee fitting and a corrosion product on the inner surface of the pitting was revealed by visual examination. Iron sulfide was revealed by chemical analysis of the scale which indicated hydrogen...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.pulp.c0047615
EISBN: 978-1-62708-230-3
.... The economizer tube leaks occurred at the end of the fin near the bottom of the economizer. A sample from a tube that had not failed showed heavy pitting attack on the inside of the tube, probably due to excess oxygen in the feedwater. Penetrant testing revealed numerous longitudinal cracks on the inside...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001338
EISBN: 978-1-62708-215-0
... is favored by loose deposits of dirt and scale and by stagnant conditions. Water with high concentrations of oxygen and carbon dioxide is a common pitting agent for copper. In any event, it is apparent that, for pitting to occur, the surface must be wet. In general, pitting usually consists of a small number...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006783
EISBN: 978-1-62708-295-2
... are galvanic corrosion, uniform corrosion, pitting, crevice corrosion, intergranular corrosion, selective leaching, and velocity-affected corrosion. In particular, mechanisms of corrosive attack for specific forms of corrosion, as well as evaluation and factors contributing to these forms, are described...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001063
EISBN: 978-1-62708-214-3
.... However, even such water becomes corrosive to stainless steel if kept stagnant for extended periods. The aggressiveness increases if the stagnant water is kept closed, without access to atmospheric oxygen. Under such conditions, pitting results ( Ref 1 ). Corrosion of the carbon steel contributed...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.petrol.c0047606
EISBN: 978-1-62708-228-0
... or passivated by a solution. The amount of oxygen that is locally present in the brine is particularly critical. A neutral hot chloride solution may locally activate the alloy, causing continuous pitting. Once the reaction has started, ferric chloride can be produced, which has an autoacceleration action...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001051
EISBN: 978-1-62708-214-3
... that this particular material is susceptible to transgranular SCC in pure water between 100 and 290 °C (212 and 550 °F) if the water contains 1 or 8 ppm O. Additionally, pitting corrosion can occur in pure water (of the same oxygen content) at 100 and 150 °C (212 and 300 °F). Transgranular cracks nucleating from...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001064
EISBN: 978-1-62708-214-3
... hydrotesting procedures was recommended to prevent similar failures. Bacterial corrosion Chemical processing equipment, corrosion Leakage Pipe, corrosion 304 UNS S30400 Biological corrosion Pitting corrosion Background The type 304 stainless steel pipelines, vessels, and tanks...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001034
EISBN: 978-1-62708-214-3
... from weld metal. Electrolytically etched in 10% oxalic acid. 100×. The cross section shown in Fig. 11 shows a closeup view of a surface pit, along with an internal “tunnel” produced by corrosion as the bacteria tunneled into the steel in an effort to seek low oxygen levels. The bacteria...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.bldgs.c9001168
EISBN: 978-1-62708-219-8
...°C completely desalinated, virtually oxygen-saturated water by steam of 0.5 atm. and 150°C. The pipes showed on the outside a reddish-brown coating with a few flat pitting holes and incipient cracks ( Fig. 1 ). The cracks were markedly widened in 180° bends ( Fig. 2 ). The interior of the pipes...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001825
EISBN: 978-1-62708-241-9
... in rough, black deposits. Near the header end of the failed tube, there were nonmetallic deposits in pits. EDS analysis of these deposits detected primarily silicon, carbon, and oxygen, with smaller concentrations of iron, calcium, potassium, chlorine, sulfur, phosphorus, aluminum, magnesium, and sodium...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.bldgs.c0091201
EISBN: 978-1-62708-219-8
... revealed contaminants consisting of chlorine, sulfur, sodium, silicon, and potassium. The area of discoloration revealed iron and oxygen only. Fig. 1 Pitting corrosion of 316L stainless steel pipe. (a) View of pitting on the outside-diameter surface at the leak location. (b) View of the inside...