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Pulverizers

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Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001620
EISBN: 978-1-62708-229-7
... Abstract Two vertical coal-pulverizer shafts at a coal-fired generation station failed after four to five years in service. One shaft was completely broken, and the other was unbroken but cracked at both ends. shaft material was AISI type 4340 Ni-Cr- Mo alloy steel, with a uniform hardness...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001730
EISBN: 978-1-62708-229-7
... Abstract A shaft can crack twice before it fails. A Detroit electric plant had this experience with one in a coal pulverizer. Because the first crack rewelded partially (by friction) in service, the pulverizer remained serviceable until the second crack developed. Coal pulverizers Shafts...
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Published: 01 January 2002
Fig. 11 6150 steel coal pulverizer shaft that failed by fatigue. (Left) Section through pulverizer showing the inner main shaft that fractured, repaired itself by friction welding, and fractured a second time. (Right) Photograph of the friction welded surface More
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Published: 01 June 2019
Fig. 1 This is a sectional view of the central shaft of a coal pulverizer which failed twice at the indicated area before the mill had to be shut down. The first crack went through the shaft, but it was rewelded by friction due to the spring pressure and the weight of grinding mechanism. More
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Published: 01 June 2019
Fig. 1 Two failed coal-pulverizer shafts. The broken shaft is on the right; the cracked shaft is on the left. The arrow indicates the position of the bowl end crack in the cracked shaft. More
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Published: 01 June 2019
Fig. 1 6150 steel coal pulverizer shaft that failed by fatigue. (Left) Section through pulverizer showing the inner main shaft that fractured, repaired itself by friction welding, and fractured a second time. (Right) Photograph of the friction welded surface More
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c0047813
EISBN: 978-1-62708-229-7
... Abstract After being in service for ten years the ball-and-race coal pulverizer was investigated after noises were noted in it. Its lower grinding ring was attached to the 6150 normalized steel outer main shaft while the upper grinding ring was suspended by springs from a spider attached...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001300
EISBN: 978-1-62708-215-0
... Abstract A bull gear from a coal pulverizer at a utility failed by rolling-contact fatigue as the result of continual overloading of the gear and a nonuniform, case-hardened surface of the gear teeth. The gear consisted of an AISI 4140 Cr-Mo steel gear ring that was shrunk fit and pinned onto...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001700
EISBN: 978-1-62708-229-7
... Abstract A straight-tube cooler type heat exchanger had been in service for about ten years serving a coal pulverizer in Georgia. Non-potable cooling water from a local lake passed through the inner surfaces of the copper tubing and was cooling the hot oil that surrounded the outer diametral...
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Published: 01 January 2002
. 1, wear of matrix by plowing, cracking, cutting as a result of plastic deformation; 2, wear thinning of fiber or tip resulting in elliptical, well-polished tip; 3, matrix cracking; 4, edge delamination and fiber fibrillation; 5, fiber cracking; 6, pulverized fiber wear debris; 7, deterioration More
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Published: 01 June 2019
Fig. 2 Optical micrograph showing example of fretted region on side surface of keyway in cracked coal-pulverizer shaft. u, undamaged area; d, damaged area. The dashed line shows the edge of the damaged area. The arrow “O” indicates the fracture origin, which corresponds to crack “A” of Fig. 3 More
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Published: 01 January 2002
of microcracking. (c) Initiation of fiber pulverization. Source: Ref 29 More
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Published: 01 January 2002
Fig. 14 Diagram of the stages of delamination caused by repeated impact on a ceramic surface. Stage 1 fracturing on the surface and crushing of debris; stage 2, extrusion of pulverized debris in interstices and compaction of a fine grained film; stage 3, nucleation of cracks along the weak More
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Published: 15 January 2021
Fig. 16 Schematic diagram of the stages of delamination caused by repeated impact on a ceramic surface. Stage 1, fracturing on the surface and crushing of debris; stage 2, extrusion of pulverized debris in interstices and compaction of a fine-grained film; stage 3, nucleation of cracks along More
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Published: 01 January 2002
Fig. 19 Scanning electron microscope micrographs of worn surfaces of PA66 unidirectional composites. (a) Carbon fiber (parallel, P) showing fiber thinning, fiber fracture, fiber pulverization (left portion) and fiber matrix debonding (middle portion). (b) Aramid fiber (AF) in the normal More
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003572
EISBN: 978-1-62708-180-1
..., was at 30% loading of short GF. The difference in the severity of the fiber damage in the 10% polyetherimide (PEI) composite due to these different grit sizes can be seen in Fig. 6(a) and (b) . The various stages of fiber cracking, cutting, and pulverization in 30% GF composite are shown in Fig. 6(c...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.machtools.c0091853
EISBN: 978-1-62708-223-5
... particles has a significant effect on the wear behavior of the grinding plates in the attrition mill, with quartz attrition leading to failure of the part in the following way. When the quartz particles are pulverized by the rubbing action between the rotating plate and the stationary plate, particles...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001850
EISBN: 978-1-62708-241-9
... in service by bulging out over a localized area. The bulging occurred at 3 O’clock position with a length, width, and height of 300, 150, and 12 mm, respectively. The location of bulging in the blow pipe was adjacent to the injection lance used for injecting pulverized coal into the furnace ( Fig. 1...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001808
EISBN: 978-1-62708-180-1
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003565
EISBN: 978-1-62708-180-1
... modes of material removal occur during impact. Brittle deformation is linked to the creation of pits (formed when material is adhesively plucked from the surface of one impacting body by the other), partial ring cracks, and delamination layers. The removed material is pulverized and compacted...