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grain boundary defects

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Published: 01 December 1992
Fig. 3 Microstucture of defective tube surface, showing grain boundaries outlined by carbides, with oxide attack at surface. Vilella's reagent. 250×. More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001217
EISBN: 978-1-62708-235-8
... decreased. Remarkably this did not occur at the boundaries of the newly formed austenitic grains but apparently at the undissolved nuclei of the original location. According to these tests a subsequent removal of this defect by solutioning is impractical because the annealing temperature is too high...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001253
EISBN: 978-1-62708-235-8
... of primary grain boundary cracks in cast ingots. Cracking (fracturing) Crankshafts Flakes (defects) Forging Ingots CK 45 Intergranular fracture Metalworking-related failures Hydrogen damage and embrittlement Octagonal cast ingots weighing 6.5 tons and made of unalloyed heat treated steel...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.bldgs.c9001171
EISBN: 978-1-62708-219-8
... pipelines, lead to the conclusion that intercrystalline corrosion in steels involved precipitation of a surplus phase at grain boundaries. Intercrystalline corrosion in austenitic stainless steels due to precipitation of chromium carbides during conditions generated due to welding and ways to avoid...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001833
EISBN: 978-1-62708-241-9
... indicated that the boiler failure was caused by grain-boundary segregation of phosphorous, tin, and nitrogen and the in-service formation of carbide films and granules on the grain boundaries. steam chest fracture high-temperature oxidation chromium alloy steel grain boundary defects scanning...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001004
EISBN: 978-1-62708-229-7
... of grain boundary phosphorus segregation exhibited a good relationship with ambient temperature Charpy data. The electrochemical polarization kinetic reactivation, EPR, approach, however, proved disappointing in that the overlapping scatter in the minimum current density, Ir, for an embrittled and a non...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001176
EISBN: 978-1-62708-229-7
... reduced in bulk from the inside and covered with a thick crumbling layer of magnetic iron oxide (Fe3-O4). This was a corrosion product resulting from the operation of the boiler. In addition, it was decarburized from the inside, and interspersed with grain boundary cracks. This form of attack is typical...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001302
EISBN: 978-1-62708-215-0
... of tensile tests conducted near the incipient melting temperature at the grain boundaries. All kingpins made by the supplier of the fractured ones were ultrasonically inspected and six more anticipated to fail were found. It was recommended that the heating of forging blanks be more carefully controlled...
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
... was cleavage, probably caused by cast-in hydrogen. The intergranular appearance resulted from heat treatment of the already cracked part, which caused the formation of grain-boundary “growth figures” on the exposed crack surfaces. It was recommended that the castings be more closely inspected for defects...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001031
EISBN: 978-1-62708-214-3
... caused ductility loss and grain-boundary separation. The excessive oxygen content in the liner was attributed to diffusion from an oxygen-rich environment that had resulted from nonuniform mixing of propellants. The internal oxygen embrittled the alloy and reduced its thermal conductivity, which resulted...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001252
EISBN: 978-1-62708-235-8
... at high initial forging temperature. Another block melted under the same conditions and immediately after the defective one, was forged into a gear ring without any trouble. This ring was free of grain boundary precipitates, but it contained only 0.012 % AI and 0.0102 % N. Cracking (fracturing...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.steel.c9001255
EISBN: 978-1-62708-232-7
.... In Fig. 2 or better in Fig. 3 , which shows the section of a fracture in another roll, it can be seen that the structure of the fracture was scaly apart from a narrow fine grained outer zone. Scaly fracture of this type occurs if the primary grain boundaries are weakened by the precipitation of poorly...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001675
EISBN: 978-1-62708-220-4
... level for Incoloy 800H, the formation of small creep voids of lenticular shape on the grain boundaries may be expected after some 50% of the useful life is used up, these lying approximately normal to the direction of the principal tensile stress. No such defects were observed. Fig. 3 General...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001106
EISBN: 978-1-62708-214-3
.... Fig. 1 Defective furnace element tubes. Fig. 2 Closeup view of attack on tubes Etched with. Testing Procedure and Results Metallography Microstructural Analysis The surface of the tube had oxidized along the grain boundaries and had extensive precipitation inside the grains...
Image
Published: 15 January 2021
Fig. 10 Interfacial regions are generally more anodic due to the presence of defect and misfit strains, which have higher strain energy and are preferential sites for corrosion. (a) Grain boundaries are more anodic than grains and thus more prone to corrosion. (b) Interphase boundaries More
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003507
EISBN: 978-1-62708-180-1
... postforming processes Process Possible defects Electroplating Hydrogen embrittlement, galvanic corrosion Heat treatment Excessive grain growth, burning of grain boundaries, brittle structure, carburization, decarburization, quench cracks Electrolytic cleaning Pitting Surface hardening...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001123
EISBN: 978-1-62708-214-3
... was different from that specified. The presence of excess aluminum and lead impurities that had segregated to the grain boundaries, coupled with an inadequate amount of magnesium, resulted in intergranular corrosion and subsequent intergranular failure. Corrosion was accelerated by storage in a humid...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001687
EISBN: 978-1-62708-220-4
... the macrovoids and the concentration of stresses at their tips, caused extensive localized plastic deformation which led to the formation of microvoids and subsequently to the spalling of the oxide film. The non-protective character of the film induced a progressive deterioration of the grain boundaries...
Image
Published: 01 June 2019
Fig. 8 Optical micrographs of the forging showing the microstructure in different regions: (a) near defect, (b) near edge. Note the grain boundary ferrite (light) in pearlite matrix (dark). More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001213
EISBN: 978-1-62708-220-4
... from 600 to 750° C and carbides have segregated at the grain boundaries; a process favored by cold work prior to annealing. The presence of such precipitates is indicated in Fig. 8 by the strong shading of the grain boundaries. At higher magnification ( Fig. 9 ) the precipitates themselves become...