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Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001321
EISBN: 978-1-62708-215-0
... chemical for the boiler feed water. Alkaline corrosion PH Water chemistry SAE 192 High-temperature corrosion and oxidation Unscheduled shutdowns occurred in boilers No. 1 and No. 3 from a bank of six boiler units in a refinery, due to failure of the horizontal support tubes...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001320
EISBN: 978-1-62708-215-0
.... Acidic conditions may have formed during a low-pH excursion that reportedly occurred several years prior. To prevent future failures, severely damaged tubing must be replaced. Internal deposit buildup must be removed by chemical cleaning to prevent further pitting. Water quality needs continued...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.design.c0047109
EISBN: 978-1-62708-233-4
... Abstract A series of poppet-valve stems fabricated from 17-4 PH (AISI type 630) stainless steel failed prematurely in service during the development of a large combustion assembly. The poppet valves were part of a scavenging system that evacuated the assembly after each combustion cycle. The...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001808
EISBN: 978-1-62708-241-9
... copper alloys, in contact with a variety of liquids, chemistries, and substances. Analytical techniques employed include stereoscopic examination, energy dispersive x-ray spectroscopy (EDS), temperature and pH testing, and metallographic analysis. The findings indicate that MIC is frequently the result...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001070
EISBN: 978-1-62708-214-3
... borderline passivity of type 316L in hot dilute sulfuric acid (about 0.1%). Inaccuracy of the testing was attributed to the presence of cupric ions in the lead-lined vessel fluids, which had been released by corrosion of the copper coils. Careful control of both temperature and pH was recommended to reduce...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001026
EISBN: 978-1-62708-214-3
... Abstract Cracks were discovered in the cast 17-4 PH stainless steel outboard leading edge flap support of an aircraft wing during overhaul inspection. Failure analysis focused on an apparently intergranular area of fracture surface. It was determined that the original mode of crack growth was...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001361
EISBN: 978-1-62708-215-0
... Abstract A 17-4 PH steering actuator rod end body broke during normal take-off. Results of failure analysis revealed that the wall thickness of the race was much below the design limits, thus causing the race to rest on the body's swaged edges rather than on the load carrying centerline of the...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.design.c0048169
EISBN: 978-1-62708-233-4
... Abstract A valve-seat retainer spring (made of 0.23 mm thick 17-7 PH stainless steel) from a fuel control on an aircraft engine was found to be broken after 3980 h of service. The two inner tabs were found to be broken off. The part was revealed to be in relative rotation against its contacting...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.design.c0091358
EISBN: 978-1-62708-233-4
..., containing citric and phosphoric acids and having a pH of 2.4 to 2.5. Investigation (visual inspection, chemical analysis, immersion testing in the soft drink, and 100x unetched micrographs) supported the conclusion that the failure was caused by the size and distribution of sulfide stringers in the alloy...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c0091640
EISBN: 978-1-62708-229-7
... Abstract A valve stem made of 17-4 PH (AISI type 630) stainless steel, which was used for operating a gate valve in a steam power plant, failed after approximately four months of service, during which it had been exposed to high-purity water at approximately 175 deg C (350 deg F) and 11 MPa...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c0048714
EISBN: 978-1-62708-229-7
... Abstract Tubes in heat exchangers, made of copper alloy C44300 and used for cooling air failed after 5 to six years of service. Air passed over the shell-side surface of the tubes and was cooled by water flowing through the tubes. Water vapor in the air was condensed (pH 4.5) on the tube...
Series: 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
... concentration of dissolved inorganic carbon (DIC), pH, and the availability of nucleation sites [ 3 ]. Some microorganisms accumulate inorganic compounds such as phosphorites, carbonates, silicates, iron, and manganese oxides [ 4 – 8 ]. It is also well known that the kidney stone formation and scale deposition...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001651
EISBN: 978-1-62708-229-7
..., Figures 1 and 2 . Sand deposits were found in the tubes. The pH of the river water varied from 7.5 to 8.3. In addition, sulphates are known to be present in the river water. All the tubes that were examined had the same hardness, 105 VHN (100g) (59 HRB equivalent). The wall thickness of all...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001739
EISBN: 978-1-62708-215-0
... tube resulted from irreversible hydrogen damage. Hydrogen damage may occur where corrosion reactions result in the production of atomic hydrogen. Heavy deposits can act as concentration sites for oxygen and acid forming contaminants. When a low-pH (acidic) condition is present, hydrogen is generated...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001791
EISBN: 978-1-62708-241-9
... striations According to complementary data, this boiler tube is composed of common carbon steel with traces of chromium, nickel, and molybdenum. The boiler is an aqua tubular type and the operation conditions are circulating water with basic pH at a 45 bar pressure and 450°C temperature. The...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001820
EISBN: 978-1-62708-241-9
... were tested in solution saturated with H 2 S and a pH of 3.5 as per NACE TM0284-96. Samples were polished to a 360 mesh, degreased and immersed in the test solutions. After the tests (72 h duration) the samples were examined for internal discontinuities using ultrasonic equipment. This auxiliary...
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
... material or manufacturing defects in the tubes. The discussion with plant personnel mentioned above indicates that the stagnant water on the shell side (OD side of the tubes) caused the pitting. Municipal potable water with neutral pH is normally not corrosive to type 316 stainless steel. In this...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001826
EISBN: 978-1-62708-241-9
...) 84 (85) barg (A) Feed water temp. Eco. Inlet (from 50% MCR up to MCR) 235 °C Boiler water pH value 9.5–10.5 Firing system Crude oil and B–C oil firing The boiler feed water and its chemistry are important contributing factors in the promotion of waterside corrosion and influencing...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006788
EISBN: 978-1-62708-295-2
... alloys, are susceptible to damage ( Ref 4 ). Titanium and its alloys appear to be generally resistant ( Ref 5 – 8 ), although modest pitting due to MIC has been demonstrated in the laboratory ( Ref 9 ). Viable microorganisms can be found over a wide range of temperature, pressure, salinity, and pH...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001048
EISBN: 978-1-62708-214-3
... soft, with pH around 7 and chlorides around 15 ppm. The cooling water treatment included continuous chlorination at the rate of 4 to 5 kg (9 to 11 lb) of chlorine per hour as a microbiological treatment. This increased the chloride level. On hot surfaces of the tubes, where the tube-side temperature...