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Acicular structure

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Image
Published: 01 August 2018
Fig. 17.41 Gray cast iron with acicular structure. Graphite flakes in a matrix of bainitic ferrite and retained austenite. ASTM A644 defines as “ausferrite” “a cast iron matrix microstructure, produced by a controlled thermal process, which consists of predominantly acicular ferrite and high More
Image
Published: 01 August 2018
Fig. 17.42 Gray cast iron with acicular structure. Deviation during heat treatment. Complex carbides (containing Mo) that were not properly dissolved in the austenitization stage of the austempering are visible. Graphite flakes in a matrix of ausferrite (see Fig. 17.41 for ausferrite More
Image
Published: 01 November 2010
Fig. D.14 Structure is acicular sigma phase, M23C6 carbide at grain boundary, and gamma prime within the gamma matrix grains. Optical microscope, original magnification 4500×. Condition: Solution treated and aged—solution annealed 4 h at 1175 °C (2150 °F) and aged 1500 h at 815 °C (1500 °F More
Image
Published: 01 January 2015
Fig. 7.12 Pure titanium bar. Acicular alpha structure produced by water quenching after heating at 1010 °C (1850 °F) for ½ h. Etchant: 10%HF-5%HNO 3 . Original magnification: 250× More
Image
Published: 01 January 2015
Fig. 7.13 Ti-6Al-4V. Acicular alpha structure and prior-beta grain boundaries formed on heating at 1060 °C (1940 °F) for ½ h and air cooling. Etchant: 10%HF-5%HNO 3 . Original magnification: 100× More
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Published: 01 August 2018
Fig. 10.65 Steel containing C = 0.5% water quenched and tempered at (a) 200 °C (390 °F): tempered martensite, well-defined acicular structure. (b) 400 °C (750 °F): tempered martensite, acicular structure less defined due to the changes happening during tempering. (c) 750 °C (1380 °F More
Image
Published: 01 August 2018
Fig. 9.68 Medium carbon steel. Pro-eutectoid ferrite and pearlite. Allotriomorphic ferrite in the prior austenite grain boundaries, Widmanstätten ferrite in primary and secondary plates. Mostly “acicularstructure. Steel with a large prior austenitic grain size, probably due to overheating More
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.tpmpa.t54480141
EISBN: 978-1-62708-318-8
... is unknown. Usually, the microstructures that result from beta annealing (or processing) are also easily recognized under the light microscope. Cooling rates govern the grain morphology resulting from beta treatments. Acicular martensitic structures are produced by rapidly cooling beta-lean alloys from...
Image
Published: 01 October 2011
), which reduced the amount of α grains and coarsened the acicular α in the matrix. (d) Solution treated at 955 °C (1750 °F), which is above the β transus. The resulting structure is coarse, acicular α (light) and aged transformed β (dark). All etched with Kroll’s reagent (ASTM 192). Original magnification More
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Published: 01 August 2018
the presence of acicular constituents. The classification “degenerated pearlite” sometimes employed, can be applied to some of the pearlite present. Acicular ferrite starts to appear in the structure. (c) This is the last sample in which pearlite is still formed. The progressive reduction of the volume More
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 1999
DOI: 10.31399/asm.tb.lmcs.t66560005
EISBN: 978-1-62708-291-4
..., acicular ferrite, coarse acicular ferrite, fine acicular ferrite , and Widmanstätten ferrite . Mehl (in Ref 4 ) records that the characteristic Widmanstätten structure is named after Aloys Joseph Franz Xaver Beck von Widmanstätten, director of the Imperial Fabrik-Producton-Cabinet, an industrial...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.spsp2.t54410113
EISBN: 978-1-62708-265-5
... or microstructures. The other structures may be austenite, martensite, or pearlite. Frequently during the formation of acicular ferrite, austenite is retained, and on cooling to room temperature, that austenite may transform partially to martensite, producing what is now commonly referred to as the martensite...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2000
DOI: 10.31399/asm.tb.ttg2.t61120013
EISBN: 978-1-62708-269-3
... and fine acicular structures can be produced, but equiaxed structures also are possible. (This topic is discussed later in this chapter.) Typical titanium microstructures are shown in Fig. 3.2 . The microstructures shown are intended to be representative but definitely not all-inclusive because the actual...
Image
Published: 01 June 2008
magnification: 250×. (b) As-forged at 955 °C (1750 °F), below the beta transus. Elongated alpha (light), caused by low reduction (20%) of a billet that had coarse, platelike alpha, in a matrix of transformed beta containing acicular alpha. Original magnification: 250×. (c) Plate, recrystallize-annealed at 925 More
Image
Published: 01 October 2012
magnification: 250×. (b) As-forged at 955 °C (1750 °F), below the β transus. Elongated α (light), caused by low reduction (20%) of a billet that had coarse, platelike α in a matrix of transformed β containing acicular α. Original magnification: 250×. (c) Plate, recrystallize annealed at 925 °C (1700 °F) 1 h More
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Published: 01 August 2018
Fig. 9.81 Structural steel containing C = 0.08%, Si = 0.19%, Mn = 1.47%, S = 0.004%, Ti = 0.012%. Determining the nucleation conditions for intragranular ferrite (acicular) in a complex nonmetallic inclusion. Simulated welding thermal cycle: heating to 1440 °C (2625 °F) for 4 s followed More
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Published: 01 August 2018
intermediate cooling and austenite transformation. Fig. 14.6 presents the effect of these microstructures on the material toughness. In all samples, polygonal ferrite and pearlite are observed. In samples (e) and (f), some acicular constituents, probably acicular ferrite, are present. Courtesy of R. N More
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 June 2008
DOI: 10.31399/asm.tb.emea.t52240527
EISBN: 978-1-62708-251-8
...-beta alloys can take different forms, ranging from equiaxed to acicular or some combination of both. Equiaxed structures are formed by working the alloy in the alpha-beta range and annealing at lower temperatures ( Fig. 28.7 ). Acicular structures ( Fig. 28.7c ) are formed by working or heat treating...
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Published: 01 December 2001
Fig. 2 Austempered ductile iron structure consisting of spheroidal graphite in a matrix of acicular ferritic plates (dark) and interplate austenitic (white) More
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Published: 01 December 2000
Fig. 3.3 Microstructures of an annealed near-alpha alloy (Ti-8Al-1Mo) after cooling from different areas of the phase field. (a) Acicular alpha. (b) Equiaxed alpha and intergranular beta. (c) Fine alpha-beta structure More