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oxide scale deposits

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Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c0048702
EISBN: 978-1-62708-220-4
... of attack and thickness of the corrosion deposit. 28×. (c) Micrograph showing the intergranular nature of the attack and undercutting of metal particles. Etched with ammonium persulfate. 110× Most copper alloys depend on the formation of a protective oxide scale for corrosion protection. When...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001482
EISBN: 978-1-62708-229-7
... was filled with an oxide scale in which were embedded particles having the appearance of metallic copper. It was concluded that the cracking that occurred at the time of re-welding was due to intergranular penetration by copper present in the deposit within the tubes, which had not been completely removed...
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
... to prolonged caustic attack that led to ruptures in areas of high stress. The escaping steam eroded the outer surface of the tube causing heavy loss of metal around the rupture points. boiler tubes stress rupture caustic corrosion carbon steel oxide scale deposits punch marks inductively coupled...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001109
EISBN: 978-1-62708-214-3
..., the deposit accumulates with each cycle through the furnace. Metallographic and chemical analyses have clearly established that the grate bar degradation was primarily caused by hot corrosion by molten salts. The molten salt destroyed the ability of the material to maintain a protective oxide scale...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001834
EISBN: 978-1-62708-241-9
... specifications. Except for a khaki-colored deposit with a maximum thickness of 2.0 mm on the fireside, the outer surface of the tube was a typical brownish color and had an oxide scale with a maximum thickness of 0.2 mm ( Fig. 1 ). Obvious localised attack marked by random corrosion pits with a maximum depth...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001658
EISBN: 978-1-62708-229-7
... the lower reheater inlet on a tube sample removed in 1979 for metallographic examination. Note that chromium is limited to the inner scale and there is a chromium rich band in the center of the scale. It appears that the 1979 deposit is predominantly of oxide from boiler tube surfaces. The reheater...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006787
EISBN: 978-1-62708-295-2
...Suggested maximum operating temperatures for select alloys in continuous, isothermal oxidizing atmospheres without excessive scaling Table 1 Suggested maximum operating temperatures for select alloys in continuous, isothermal oxidizing atmospheres without excessive scaling Alloy...
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
... by Sandvik AB, Sweden. (i) CR30A is a proprietary grade developed by Nippon-Kokan Steel Corporation, Japan. Heat-transfer factors and thermal conductivities of scale deposits Table 4 Heat-transfer factors and thermal conductivities of scale deposits Heat-transfer factors (a) h i...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001396
EISBN: 978-1-62708-229-7
... be employed to detect affected tubes. Fig. 12 Massive magnetite scale on internal surface Fig. 13 Scale associated with corroded area Chemical analysis of deposits taken from tubes affected by on-load corrosion showed them to be composed of approximately 50% iron oxide (magnetite, Fe 3...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001816
EISBN: 978-1-62708-180-1
... to form iron oxide: (Eq 1) 4 H 2 O + 3 Fe → 3 Fe 3 O 4 + 4 H 2 Furnace walls may also have other deposits from impurities in the boiler feedwater. Because these deposits and scale have a lower thermal conductivity than the steel tube, the net effect is an increase...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003555
EISBN: 978-1-62708-180-1
...Suggested maximum temperatures for various alloys in continuous, isothermal oxidizing atmospheres without excessive scaling Table 1 Suggested maximum temperatures for various alloys in continuous, isothermal oxidizing atmospheres without excessive scaling Alloy designation Temperature...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006824
EISBN: 978-1-62708-329-4
... continuously fracture and remove the protective oxidation scales at the surface of the component in a process known as heat erosion. One of the characteristic signs of heat erosion is a lack of alloy depletion under the eroded surface, because the recession of the surface progresses ahead of any solid...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001666
EISBN: 978-1-62708-229-7
... deposit. The bulkier and loose outer scale was removed from representative areas and submitted for chemical analysis by x-ray diffraction, ion chromatography, and elemental analysis. The majority of the scale consisted of iron oxides; magnetite, hematite and FeO(OH). Most of the areas sampled contained...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001281
EISBN: 978-1-62708-215-0
.... Surface Examination Metallography Chemical Analysis/Identification Alloy surfaces exposed to high temperatures and gas environments can become coated with foreign deposits (sulfates, oxides, chlorides, etc.) from combustion air or fuel contaminants. Corrosion products can react with or dissolve...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001817
EISBN: 978-1-62708-180-1
... but brittle at or slightly above room temperature. Another temperature-related problem is scaling and oxidation due to excessive temperatures. Creep and stress rupture also occur because of excessive temperatures, as discussed in the article “Creep and Stress-Rupture Failures” in this Volume...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006813
EISBN: 978-1-62708-329-4
..., cracks in mill scale, and local breakdown of protective films, may also initiate crevice-corrosion attack. Underdeposit corrosion often occurs as a result of scale deposition. Corrosion of this type is often associated with water that contains dissolved solids in comparatively small concentrations...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006782
EISBN: 978-1-62708-295-2
... increases as the oxidizing power of the solution increases. The increase in rate is exponential and yields a straight line when plotted on a semilogarithmic scale, as in Fig. 1 . The oxidizing power of the solution is controlled by both the specific oxidizing power of the reagents and the concentration...
Series: 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
... is critical, softened acetate tape can be used to remove adherent deposits. This method also retains the deposits removed for further examination if necessary. If the failure analysis does not involve preservation of a fracture surface, fine sandblasting of the base metal may be useful to remove scale...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001331
EISBN: 978-1-62708-215-0
.... The local temperature of the metal under these deposits also increases, which enhances further reaction and metal dissolution. These reasons underlie the fact that metal loss was found only under the thick oxide scale. Hydrogen produced during the corrosion process easily diffuses into the steel...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001480
EISBN: 978-1-62708-229-7
... intergranular penetration by molten copper. Particles of copper were seen in scale deposits on the bore of the tube. The tube in general showed a ferritic structure with partially spheroidized carbide. The fact that fusion of the copper had occurred indicated temperatures of 1100 deg C (2012 deg F) had been...