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Lamellar structure

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Published: 01 January 2002
Fig. 7 Micrograph of impeller specimen. This structure, which consists of lamellar carbides in an austenitic matrix, is considered normal for this material. Etched with V2A reagent. 500×. Source: Ref 11 More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001258
EISBN: 978-1-62708-235-8
... sides of the fracture of 300 mm each. Missing in the lamellar surface structure, with the exception of the remnants of a coarse network, were the pre-eutectically precipitated carbides to be expected in this steel. Surrounding the ferritic region in the surface structure, a ring of lamellar pearlite...
Image
Published: 01 June 2019
Fig. 6 Examples of some of the microstructures of the failed couplings (transverse, T; longitudinal, L). (c) Coarse α-matrix grains with a fine, spaced lamellar structure κ IIII phase at grain boundaries and a low concentration of κ IIV precipitates at grain interiors. (d) Large α-matrix More
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Published: 01 December 1992
Fig. 3 Micrographs of grate bar that suffered hot corrosion. (a) Unetched, showing external oxide scale and internal sulfide particles (light gray area). (b) Etched, showing external oxide scale along with precipitated carbides (dark gray area)and lamellar structure consisting of austenite More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c0089793
EISBN: 978-1-62708-235-8
... Lamellar structure Lamellar tearing Motor amatures Thermal stresses Welded joints Fe-0.21C-0.77Mn Joining-related failures During the final shop welding of a large armature for a direct-current motor (4475 kW, or 6000 hp), a large bang was heard, and the welding operation stopped. When the weld...
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
... at the grain boundaries and coarsen. The typical lamellar structure of pearlite changes to a particle structure. Such pearlite steel exhibits a tendency toward pearlite spheroidisation after long-term exposure to high temperatures. Structural changes form cavities and cause internal damage [ 6 ]. Thus...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.conag.c9001588
EISBN: 978-1-62708-221-1
... ductility direction of the transition joint plate, lamellar tearing of plate material occurred at the boxed I-beam fillet weld attachment. Brittle fracture of this joint precipitated global collapse of the truss structure. Bridges (structures) Ore conveyors Structural steel Brittle fracture...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.marine.c9001141
EISBN: 978-1-62708-227-3
... 1967 . 13. Watanabe M. , “The Pull-Out Type Fracture in Rolled Steel Plate” , Symposium on Welding in Ship Building, The Institute of Welding , pp. 219 – 225 , London 1961 . 14. Takeshi Y. , “Lamellar Tearing and Marine Structures” , Welding and Metal Fabrication , Volume...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001184
EISBN: 978-1-62708-235-8
... Abstract Examples of metallic inclusions in steels of various types are presented. The structure of an inclusion in an annealed Fe-1C-1.5Cr steel consisted of ferrite with lamellar pearlite. The carbon content of the inclusion was therefore considerably lower than that of the chromium steel...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.conag.c9001139
EISBN: 978-1-62708-221-1
... of the failure include the use of bolts in lieu of welding, a welding schedule that reduces the propensity of lamellar tearing, and the use of an alloy that precludes lamellar tearing. However, if abuse of the crane was the primary cause of failure, none of these recommendations would have prevented...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c9001186
EISBN: 978-1-62708-234-1
... of the fracture, but they had no effect on the breakage of the wire. Away from the fracture area, the wire had a normal structure of hyperfine lamellar pearlite (sorbite) of a “patented” and cold drawn steel wire. In the vicinity of the fracture, the cementite of the pearlite was partially spheroidized, while...
Image
Published: 01 June 2019
Fig. 14 TEM replica of a fracture surface of a compact-tension test specimen showing features identified as lamellar pearlite structure, sometimes mistaken for fatigue striations 9 More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.conag.c9001442
EISBN: 978-1-62708-221-1
... through the fillet welds and zone showed lamellar tearing, which confirmed that failure had occurred in weld metal adjacent to the fusion face of the fillet to the vane. Results of the investigation indicated that the primary cause of failure of the impeller was the development of fatigue cracks from...
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
..., and probably not protective. Typical unetched and etched microstructures near the top surface of the grate bar are shown in Fig. 3 , respectively. Upon etching, the internal microstructure showed coalescence of carbide particles outlining the cored cast structure, as well as the presence of a lamellar...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c9001688
EISBN: 978-1-62708-234-1
... suffered less oxidation had a structure of ferrite and lamellar pearlite across the wall ( Figure 1a ) while the others had a structure of ferrite and spheroidized pearlite with extensive decarburization at the outer surface ( Figure 1b ), and a lesser degree of decarburization at the inside. Fig. 1...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001340
EISBN: 978-1-62708-215-0
... in.), consistent with the specified thickness, while along the fire-side, tube wall thickness measured as low as 0.178 cm (0.070 in.) near the fissures. Metallography Optical metallography on the coldside of tube 4 revealed a ferritic structure with small islands of lamellar pearlite, typical...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c9001165
EISBN: 978-1-62708-234-1
... as well as the pump housing consisted of cast iron alloyed with nickel. Chemical analysis of the non-corroded part of the impeller showed the following composition [in wt.%]: C ges./total Graphit/grapite 3,14 2,55 Ni S 3,12 0,15 The microstructure consisted of lamellar...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.conag.c9001497
EISBN: 978-1-62708-221-1
... of the remaining teeth, section it midway from both ends, and prepare a sample for a case hardness traverse and microscopic examination. From the case hardness survey and the microscopic examination, the following results were observed: Core structure: An equal admixture of lamellar pearlite and low...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.design.c9001259
EISBN: 978-1-62708-233-4
... G the cementite was somewhat stronger spheroidized ( Fig. 1 ) than in that of shipments S1 ( Fig. 2 ) and S2 ( Fig. 3 ), whose lamellar pearlite structure was still recognizable. This is most likely connected with the fine grained steel's lower supercooling propensity of the austenitic...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.marine.c9001617
EISBN: 978-1-62708-227-3
... concentration of fine κ IIV precipitates within selected α grains. Fig. 6 Examples of some of the microstructures of the failed couplings (transverse, T; longitudinal, L). (c) Coarse α-matrix grains with a fine, spaced lamellar structure κ IIII phase at grain boundaries and a low concentration of κ...