Skip Nav Destination
Close Modal
By
Richard L. Colwell
By
J. Robert Kattus
By
Richard L. Colwell
By
Philip J. Kenny
By
Robert D. Port
By
Albert M. Olszewski
By
Leonard J. Hodas
By
S.R. Freeman
By
H.S. Khatak, J.B. Gnanamoorthy, P. Rodriguez
By
Fahmida Hossain, Veda-Anne Ulčickas
By
Cássio Barbosa, Jôneo Lopes do Nascimento, José Luiz Fernandes, Ibrahim de Cerqueira Abud
By
Cassio Barbosa, Ibrahim de Cerqueira Abud, Tatiana Silva Barros, Sheyla Santana de Carvalho, Ieda Maria Vieira Caminha
By
S. Maruthamuthu, P. Dhandapani, S. Ponmariappan, S. Sathiyanarayanan, S. Muthukrishnan ...
Search Results for
Nitric acid, environment
Update search
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
NARROW
Format
Topics
Book Series
Date
Availability
1-20 of 35
Search Results for Nitric acid, environment
Follow your search
Access your saved searches in your account
Would you like to receive an alert when new items match your search?
1
Sort by
Book Chapter
Intergranular Corrosion in an E-Brite-Clad Ferralium Tube Sheet in Nitric Acid Service
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001047
EISBN: 978-1-62708-214-3
... the inlet and replacement of the floating skirt with virgin material (i.e., material unaffected by weld repairs). Chemical processing equipment Condenser tubes, corrosion Condensers (liquefiers) Heat-affected zone Nitric acid, environment Repair welding Tube plate, corrosion Welded joints...
Abstract
An E-Brite /Ferralium explosively bonded tube sheet in a nitric acid condenser was removed from service because of corrosion. Visual and metallographic examination of tube sheet samples revealed severe cracking in the heat-affected zone between the outer tubes and the weld joining the tube sheet to the floating skirt. Cracks penetrated deep into the tube sheet, and occasionally into the tube walls. The microstructures of both alloys and of the weld appeared normal. Intergranular corrosion characteristic of end-grain attack was apparent. A low dead spot at the skirt / tube sheet joint allowed the Nox to condense and subsequently reboil. This, coupled with repeated repair welding in the area, reduced resistance to acid attack. Intergranular corrosion continued until failure. Recommendations included changing operating parameter inlet to prevent HNO3 condensation outside the inlet and replacement of the floating skirt with virgin material (i.e., material unaffected by weld repairs).
Book Chapter
Failure of Nickel-Base Superalloy Heat-Exchanger Tubes in a Black Liquor Heater
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001311
EISBN: 978-1-62708-215-0
... to type 304 stainless steel tubing made without dendritic weld seams was recommended. Heat-affected zone Nitric acid, environment Papermaking Welded joints, corrosion Inconel 600 UNS N06600 Uniform corrosion Galvanic corrosion Background Several nickel-base superalloy (UNS N06600...
Abstract
Several nickel-base superalloy (UNS N06600) welded heat-exchanger tubes used in processing black liquor in a kraft paper mill failed prematurely. Leaking occurred through the tube walls at levels near the bottom tube sheet. The tubes had been installed as replacements for type 304 stainless steel tubes. Visual and stereoscopic examination revealed three types of corrosion on the inside surfaces of the tubes: uniform attack, deeper localized corrosive attack, and accelerated uniform attack. Metallographic analysis indicated that pronounced dissimilar-metal corrosion had occurred in the base metal immediately adjacent to the weld seam. The corrosion was attributed to exposure to nitric acid cleaning solution and was accelerated by galvanic differences between the tubes and a stainless steel tube sheet and between the base metal of the tubes and their dendritic weld seams. A change to type 304 stainless steel tubing made without dendritic weld seams was recommended.
Book Chapter
Stress-Corrosion Cracking of a Teflon-Lined Steel Pipe in Sulfuric Acid Service
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001066
EISBN: 978-1-62708-214-3
... impermeable to the diffusion of ionic species was recommended. Chemical processing equipment Nitric acid, environment Spools, corrosion Sulfuric acid, environment Teflon-lined carbon steel Intergranular corrosion Stress-corrosion cracking Background A flanged 100 mm (4 in.) diam low-carbon...
Abstract
A flanged 100 mm (4 in.) diam low-carbon steel spool piece lined with Teflon was removed from a sulfuric acid denitrification system after cracks were observed in the painted coating. Visual and microstructural examination along with SEM fractography revealed scaled iron oxides on all opened crack surfaces. The surfaces had a faceted morphology, indicating intergranular fracture. Cracks originated at the interface between the tube and the Teflon liner Corrosion products were found caked into the intergranular region between the liner and the spool. The portion of the liner that had been exposed to the process stream was discolored. Failure of the spool was attributed to stress-corrosion cracking promoted by the presence of nitrates. Nitric acid contaminant in the sulfuric acid stream had diffused through the liner and accumulated in the annular space. Use of a liner that is more impermeable to the diffusion of ionic species was recommended.
Book Chapter
Stress Corrosion Failure of Impeller of Centrifugal Air Compressor
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001399
EISBN: 978-1-62708-220-4
... stresses would be greatest. The compressor intake was situated in the vicinity of nitric acid pumps which had a history of leakage troubles, and which had evidently given rise to the nitrates found on the impeller. Air compressors Chlorides Corrosion environments Impellers Nitric acid Pumps Fe...
Abstract
An air compressor was installed at a chemical plant in which nitric acid was produced by burning ammonia with air. It was a 5000 hp, 5-stage centrifugal machine running at 6000 rpm, compressing air to 5 atm. Failure of the first stage impeller occurred due to a segment from the back plate becoming detached. On the remaining portion, cracks were visible running between the holes for rivets by which the vanes were attached. Metallographic examination of selected sections from the backplate revealed the material to be in the hardened and tempered condition, and the cracking to have initiated on the internal surface of the plate at the crevice between the plate and the vane. It was evident that the impeller failed by stress-corrosion cracking, which initiated in the crevice between the vanes and back plate and propagated through the plate along the line of the rivets where working stresses would be greatest. The compressor intake was situated in the vicinity of nitric acid pumps which had a history of leakage troubles, and which had evidently given rise to the nitrates found on the impeller.
Book Chapter
Analysis of Contaminants on Grain-Boundary Fractures
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c0045918
EISBN: 978-1-62708-235-8
..., oxygen, nitrogen, fluorine, and chlorine. Investigation into the processing history of the part showed the tenacious oxide film formed by the affinity of niobium for oxygen - even when heat treated in a vacuum – was removed with a combination of strong acids: nitric, hydrochloric, hydrofluoric...
Abstract
Cracks, with no other damage, were observed in a niobium alloy (Nb-106) part when it was pulled from several months of protective storage for assembly into a rocket nozzle. SEM views showed the cracks to be intergranular, with contaminant particles on a large number of the grain facets. EDX analysis showed they consisted of niobium and fluorine. Plastic replicas, prepared by standard TEM techniques, were analyzed with selected-area electron diffraction, showing a pattern match for niobium tetrafluoride. Auger analyses showed electron spectra containing peaks representing carbon, oxygen, nitrogen, fluorine, and chlorine. Investigation into the processing history of the part showed the tenacious oxide film formed by the affinity of niobium for oxygen - even when heat treated in a vacuum – was removed with a combination of strong acids: nitric, hydrochloric, hydrofluoric, and lactic, resulting in the contaminants found on the surface. Thus, residues of the cleaning acid on the part had caused SCC during storage, with the tensile stresses necessary to generate SCC assumed to have been residual stresses from the heat treatment. Recommendation was made that more stringent cleaning procedures to remove any trace of the cleaning acids be used.
Book Chapter
Bacterial-Induced Corrosion of AISI Type 304 Stainless Steel Tanks
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001655
EISBN: 978-1-62708-220-4
... segregation in the original plate served as preferential corrosion sites. Had the tanks been hydrostatically tested in a proper manner, the pitting may not have occurred. Corrosion environments Nitric acid Sewage Solvents Storage tanks 304L UNS S30403 Pitting corrosion Biological corrosion...
Abstract
This investigation involved two AISI 304L acid storage tanks and one AISI 304L spent solvent tank from a sewage treatment facility. After installation, these tanks were hydrostatically tested using sewage effluent. No leaks were found and after a year or two, the tanks were drained and filled with nitric acid in preparation for service. Three weeks later the two acid tanks were found to be leaking from the bottom. Samples from the spent solvent tank revealed that pitting was located in a depressed area near a suction hole, beneath a black residue. It was concluded that the acid tanks failed by chloride-induced pitting initiated by microbial activity. Further, the spent solvent tank failed by a similar, but anaerobic mechanism. The use of the effluent for the hydrostatic test and the failure to remove it and clean and dry the tanks was the primary cause of failure. Localized carbide segregation in the original plate served as preferential corrosion sites. Had the tanks been hydrostatically tested in a proper manner, the pitting may not have occurred.
Book Chapter
Corrosion and Cracking of the Internal Surfaces of a Black Liquor Digester
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001049
EISBN: 978-1-62708-214-3
.... 8 Micrograph showing overlapping regions of dendrites. Etched in electrolytic nitric acid. 15×. Fig. 9 Micrograph showing niobium carbides in interdendritic spaces. Etched in electrolytic nitric acid. 1000×. Crack Origins/Paths Open cracks ran along the dendrites in some...
Abstract
Routine inspections of a carbon steel wood pulp digester revealed a sharply increasing number of cracks in the overlay metal on the internal surface of the digester after 1 and 2 years of service. The weld overlay was composed of type 309 stainless steel on the top fourth of the digester and of a proprietary high-nickel material on the bottom three-fourths. Examination revealed three distinct modes of deterioration. General corrosion was linked to the use of unspecified overlay metal. Cracking resulted during installation from the use of a material susceptible to hot cracking. Deep corrosion fissures then developed at hot crack sites as a result of crevice corrosion. Use of the appropriate overlay material was recommended.
Book Chapter
Dealloying of a Nickel–Aluminum Bronze Impeller
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001809
EISBN: 978-1-62708-241-9
... a Iron content should not exceed the nickel content Fig. 3 Typical microstructure in bulk material containing mostly alpha phase ( a ) 100× and ( b ) 500×, etchant: 45 mL nitric acid and 45 mL acetic acid Fig. 4 Selectively attacked region near the surface contained dealloying...
Abstract
A brackish water pump impeller was replaced after four years of service, while its predecessor lasted over 40 years. The subsequent failure investigation determined that the nickel-aluminum bronze impeller was not properly heat treated, which made the impeller susceptible to aluminum dealloying. The dealloying corrosion was exacerbated by erosion because the pump was slightly oversized. The investigation recommended better heat treating procedures and closer evaluation to ensure that new pumps are properly sized.
Book Chapter
Explosion of the Terra Ammonium Nitrate Plant, Port, Neal, Iowa
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.usage.c9001584
EISBN: 978-1-62708-236-5
... evidence. We also examined titanium nitric acid spargers after their removal from ammonium nitrate (AN) neutralizer service. Statements of fact, witnesses, photographs, and documents containing information on the plant operation and maintenance prior to the explosion, observations made after...
Abstract
On 13 Dec 1994, two massive detonations leveled portions of an ammonium nitrate plant near Sioux City, IA. The primary explosion allegedly occurred in defectively-designed titanium sparger piping inside the neutralizer vessel. Investigation however, revealed the explosion occurred because of unsafe plant operations and poor maintenance procedures. Specifically, the ammonium nitrate within the 18,000 gal capacity neutralizer vessel had become contaminated and made highly acidic. The operators then injected superheated steam directly into the ammonium nitrate in the neutralizer vessel.
Book Chapter
Forms of Corrosion
Available to PurchaseSeries: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003548
EISBN: 978-1-62708-180-1
... in the environment and is carried away or produces a loosely adherent, porous coating now greater in thickness. Because of the porosity in the oxidation (rust), this metal is still considered active or able to continue degrading. Coating specialists have been able to formulate a phosphoric-acid-based compound...
Abstract
This article addresses the forms of corrosion that contribute directly to the failure of metal parts or that render them susceptible to failure by some other mechanism. It describes the mechanisms of corrosive attack for specific forms of corrosion such as galvanic corrosion, uniform corrosion, pitting and crevice corrosion, intergranular corrosion, and velocity-affected corrosion. The article contains a table that lists combinations of alloys and environments subjected to selective leaching and the elements removed by leaching.
Book Chapter
Intergranular Corrosion of an Aluminum Alloy Ship Hull
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.marine.c0091350
EISBN: 978-1-62708-227-3
... Corrosion of 5xxx Series Aluminum Alloys by Weight Loss after Exposure to Nitric Acid (NAWLT Test),” G 67, Wear and Erosion; Metal Corrosion , Vol 03.02 , Annual Book of ASTM Standards , American Society for Testing and Materials Selected Reference Selected Reference • Freeman S.R...
Abstract
Cracks occurred in a new ship hull after only three months in service. It was noted that the 5xxx series of aluminum alloys are often selected for weldability and are generally very resistant to corrosion. However, if the material has prolonged exposure at slightly elevated temperatures of 66 to 180 deg C (150 to 350 deg F), an alloy such as 5083 can become susceptible to intergranular corrosion. Investigation (visual inspection, corrosion testing, SEM images) supported the conclusion that the cracks occurred because during exposures to chloride solutions like seawater, galvanic couples formed between precipitates and the alloy matrix, leading to severe intergranular attack. No recommendations were made.
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
... into a pitting mechanism if the microcells develop enough to produce acidic gradients within the micropits where the graphite nodules lie or are dislodged. Uniform corrosion occurring by the microelectrolytic or galvanic cell in the ductile cast iron is shown in Fig. 8 . Observe the initial stages of micropits...
Abstract
Corrosion is the electrochemical reaction of a material and its environment. This article addresses those forms of corrosion that contribute directly to the failure of metal parts or that render them susceptible to failure by some other mechanism. Various forms of corrosion covered 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. These reviews of corrosion forms and mechanisms are intended to assist the reader in developing an understanding of the underlying principles of corrosion; acquiring such an understanding is the first step in recognizing and analyzing corrosion-related failures and in formulating preventive measures.
Book Chapter
Metallurgical Analysis of Steam Turbine Rotor Disc
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001362
EISBN: 978-1-62708-215-0
... Abstract Numerous cracks observed on the surface of a forged A470 Class 4 alloy steel steam turbine rotor disc from an air compressor in a nitric acid plant were found to be the result of caustic induced stress-corrosion cracking (SCC). No material defects or anomalies were observed in the disc...
Abstract
Numerous cracks observed on the surface of a forged A470 Class 4 alloy steel steam turbine rotor disc from an air compressor in a nitric acid plant were found to be the result of caustic induced stress-corrosion cracking (SCC). No material defects or anomalies were observed in the disc sample that could have contributed to crack initiation or propagation or secondary crack propagation. Chlorides detected in the fracture surface deposits were likely the primary cause for the pitting observed on the disc surfaces and within the turbine blade attachment area. It was recommended that the potential for water carryover or feedwater induction into the turbine be addressed via an engineering evaluation of the plant's water treatment procedures, steam separation equipment, and start-up procedures.
Book Chapter
Analysis and Prevention of Corrosion-Related Failures
Available to PurchaseSeries: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003549
EISBN: 978-1-62708-180-1
... corrosion-resistant properties to a passive surface film. The naturally occurring passive film is usually enhanced with immersion in a hot nitric acid solution or steam. For example, stainless steel surgical implants develop this passive layer when the implants are sterilized in steam. The exact nature...
Abstract
This article provides an overview of the electrochemical nature of corrosion and analyzes corrosion-related failures. It describes corrosion failure analysis and discusses corrective and preventive approaches to mitigate corrosion-related failures of metals. These include: change in the environment; change in the alloy or heat treatment; change in design; use of galvanic protection; use of inhibitors; use of nonmetallic coatings and liners; application of metallic coatings; use of surface treatments, thermal spray, or other surface modifications; corrosion monitoring; and preventive maintenance.
Book Chapter
Failure of Admiralty Brass Condenser Tubes
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001310
EISBN: 978-1-62708-215-0
... of salts in the corrosion deposit. In addition to ammonia, a number of environments can cause cracking, such as oxygen and carbon dioxide with ammonia, hydrogen sulfide, air contaminated with sulfur and nitrogen oxides, nitrates, phosphates, alkalis, chlorides, hydrogen fluoride, and nitric acid ( Ref 1...
Abstract
Leaks developed in 22 admiralty brass condenser tubes. The tubes were part of a condenser that was being used to condense steam from a nuclear power plant and had been in operation for less than 2 years. Analysis identified three types of failure modes: stress-corrosion cracking, corrosion under deposit (pitting and crevice), and dezincification. Fractures were transgranular and typical of stress-corrosion cracking. The primary cause of the corrosion deposit was low-flow conditions in those parts of the condenser where failure occurred. Maintenance of proper flow conditions was recommended.
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003553
EISBN: 978-1-62708-180-1
... ∼6 mm. (b) Enlarged view of the cracks; 10% oxalic acid electrolytic etch, picture width ∼1.5 mm. Courtesy of Mohan Chaudhari, Columbus Metallurgical Services Preconditions leading to SCC include a variety of materials conditions such as tensile residual stresses, work hardening, surface...
Abstract
This article commences with a discussion on the characteristics of stress-corrosion cracking (SCC) and describes crack initiation and propagation during SCC. It reviews the various mechanisms of SCC and addresses electrochemical and stress-sorption theories. The article explains the SCC, which occurs due to welding, metalworking process, and stress concentration, including options for investigation and corrective measures. It describes the sources of stresses in service and the effect of composition and metal structure on the susceptibility of SCC. The article provides information on specific ions and substances, service environments, and preservice environments responsible for SCC. It details the analysis of SCC failures, which include on-site examination, sampling, observation of fracture surface characteristics, macroscopic examination, microscopic examination, chemical analysis, metallographic analysis, and simulated-service tests. It provides case studies for the analysis of SCC service failures and their occurrence in steels, stainless steels, and commercial alloys of aluminum, copper, magnesium, and titanium.
Book Chapter
Analysis and Prevention of Environmental- and Corrosion-Related Failures
Available to PurchaseSeries: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006782
EISBN: 978-1-62708-295-2
..., stainless steel owes its corrosion-resistant properties to a passive surface film. The naturally occurring passive film is usually enhanced with immersion in a hot nitric acid solution or steam. For example, stainless steel surgical implants develop this passive layer when the implants are sterilized...
Abstract
Corrosion is the deterioration of a material by a reaction of that material with its environment. The realization that corrosion control can be profitable has been acknowledged repeatedly by industry, typically following costly business interruptions. This article describes the electrochemical nature of corrosion and provides the typical analysis of environmental- and corrosion-related failures. It presents common methods of testing of laboratory corrosion and discusses the processes involved in the prevention of environmental- and corrosion-related failures of metals and nonmetals.
Book Chapter
Failure Analysis of Two Stainless Steel Based Components Used in an Oil Refinery
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001819
EISBN: 978-1-62708-241-9
... steel) was sectioned to obtain samples for microstructural analysis, SEM fractographic analysis, and hardness tests. Samples for microstructural analysis were subjected to standard metallographic preparation: grinding (100– 600 meshes), diamond paste polishing (6–1 μm), and etching with a 30 mL nitric...
Abstract
The shafts on two centrifugal pumps failed during use in a petroleum refinery. Light optical microscopy and scanning electron microscopy were used to analyze the damaged materials to determine the cause of failure. The results showed that one shaft, made of duplex stainless steel, failed by fatigue fracture, and the other, made of 316 austenitic stainless steel, experienced a similar fracture, which was promoted by the presence of nonmetallic inclusion particles.
Book Chapter
Microscopic Analysis of Fractured Screws Used as Implants in Bone Fixation
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001804
EISBN: 978-1-62708-241-9
... (100–600 mesh), polishing (diamond paste: particles with 6, 3, and 1 lm grain size) and etching (solution with 10 ml acetic acid, 10 ml nitric acid, 15 ml hydrochloric acid, and 5 drops of glycerin for about 3 min). Samples of the same materials with fractured surfaces were analyzed in a SEM...
Abstract
A stainless steel screw securing an orthopedic implant fractured and was analyzed to determine the cause. Investigators used optical and scanning electron microscopy to examine the fracture surfaces and the microstructure of the austenitic stainless steel from which the screw was made. The results of the study indicated that the screw failed due to fatigue fracture stemming from surface cracks generated by stress concentration likely caused by grooves left by improper machining.
Book Chapter
Scale Formation by Calcium-Precipitating Bacteria in Cooling Water System
Available to PurchaseSeries: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001769
EISBN: 978-1-62708-241-9
...% nitric acid at 60 °C for 5 min in a water bath followed by gentle cleaning with trichloroethylene. These coupons were autoclaved at 121 °C at 15 psi for 15 min. The autoclaved coupons were immersed in calcium precipitating bacterial culture system described above over a period of 2–3 weeks...
Abstract
This study examines the role of calcium-precipitating bacteria (CPB) in heat exchanger tube failures. Several types of bacteria, including Serratia sp. (FJ973548), Enterobacter sp. (FJ973549, FJ973550), and Enterococcus sp. (FJ973551), were found in scale collected from heat exchanger tubes taken out of service at a gas turbine power station. The corrosive effect of each type of bacteria on mild steel was investigated using electrochemical (polarization and impedance) techniques, and the biogenic calcium scale formations analyzed by XRD. It was shown that the bacteria contribute directly to the formation of calcium carbonate, a critical factor in the buildup of scale and pitting corrosion on heat exchanger tubes.
1