Crystallography of M23C6 and M6C precipitated in a low alloy steel

Kuo, K. H.; Jia, Chunxu

doi:10.1016/0001-6160(85)90193-2

Cited by 64 publications

(30 citation statements)

References 8 publications

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“…Using selected area diffraction (SAD) analysis, the Crrich precipitates were found to have a face-centered-cubic (FCC) crystal structure with a lattice parameter of approximately 1.05 nm, i.e., within the reported values of 1.05-1.074 nm for the M 23 C 6 (M representing Cr and Fe) type carbides, [17][18][19][20][21][22] which are commonly found in stainless steels. M 6 C (M representing Cr, Fe, and Mo) is another common carbide in the stainless steels with an FCC crystal structure and a lattice parameter of 1.085-1.128 nm, [18][19][20][21][22] which is slightly larger than that of the M 23 C 6 type carbides.…”

Section: Resultsmentioning

confidence: 80%

“…M 6 C (M representing Cr, Fe, and Mo) is another common carbide in the stainless steels with an FCC crystal structure and a lattice parameter of 1.085-1.128 nm, [18][19][20][21][22] which is slightly larger than that of the M 23 C 6 type carbides. There is evidence that M 6 C forms from M 23 C 6 when the Mo content of the precipitates increases.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, such reflections will be absent in the SAD pattern taken parallel to the [001] zone axis. [18][19][20] It must be noted that in SAD patterns taken from zone axes other than the [001], the forbidden reflections in the M 6 C may appear because of the multiple diffraction. The SAD pattern, which is parallel to the [001] crystal direction of the precipitate shown in Figure 7(e), shows the presence of the {200} reflections.…”

Section: Resultsmentioning

confidence: 99%

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Ridging Control in Transformable Ferritic Stainless Steels

Mola

Jung

Park

et al. 2011

Metall Mater Trans A

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An alloy design concept leading to an improved ridging resistance in the transformable ferritic stainless steels is introduced. It is based on achieving a small c-phase fraction at the ingot soaking temperature. The c-phase fraction is then increased to a maximum value during the early stages of hot rolling. The nucleation of c-phase islands in the ferritic matrix increases the fraction of transformed ferrite. The multiplicity of crystallographic orientations resulting from the afic and cfia transformations leads to a pronounced weakening of the as-cast texture and an increased ridging resistance.

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Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Ridging Control in Transformable Ferritic Stainless Steels

Mola

Jung

Park

et al. 2011

Metall Mater Trans A

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“…[3][4][5][6][7][8][9][10][11][12] The M 3 C carbide, named cementite, with an orthorhombic crystal structure is the most well-known carbide in steels.…”

Section: Introductionmentioning

confidence: 99%

A Eutectoid Reaction for the Decomposition of Austenite into Pearlitic Lamellae of Ferrite and M23C6 Carbide in a Mn-Al Steel

Cheng

Hwang

2011

Metall Mater Trans A

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We discovered a eutectoid reaction in an Fe-13.4Mn-3.0Al-0.63C (wt pct) steel after solution heat treatment at 1373 K (1100°C) and holding at temperatures below 923 K (650°C). The steel is single austenite at temperatures from 1373 K to 923 K (1100°C to 650°C). A eutectoid reaction involves the replacement of the metastable austenite by a more stable mixture of ferrite and M 23 C 6 phases at temperatures below 923 K (650°C). The mixture of ferrite and M 23 C 6 is in the form of pearlitic lamellae. The morphology of the lamellae of the product phases is similar to that of pearlite in steels. Thus, we found a new pearlite from the eutectoid reaction of the Mn-Al steel featuring c fi a + M 23 C 6 . A Kurdjumov-Sachs (K-S) orientation relationship exists between the pearlitic ferrite (a) and M 23 C 6 (C6) grains, i.e., (110) a // (111) C6 and [111] a // [011] C6 . The upper temperature limit for the eutectoid reaction is between 923 K and 898 K (650°C and 625°C).

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“…Os borocarbonetos de ferro, que atuam diretamente no aumento da temperabilidade, possuem estrutura cristalina semelhante aos compostos M 23 C 6 , existentes no sistema Fe-Cr-C. [24] Reportados pela primeira vez em 1954, os borocarbonetos de ferro Fe 23 (B,C) 6 , predominantes nos aços ao boro, são compostos complexos que possuem estrutura CFC com parâmetro de rede aproximadamente igual a 10,6 Å. A ocorrência do borocarboneto M 23 (B,C) 6 é a característica microestrutural mais marcante em aços baixa-liga com adição de boro.…”

Section: Sistema Fe-b-cunclassified

Produção e caracterização de barras laminadas do aço ao boro DIN 39MnCrB6-2

Costa¹

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Boron added steels in quenched and tempered condition have been used in a large number of applications with mechanical properties and low cost requirements, i.e., automotive, petrochemical and O&G industries. For its great use and increasing demand for new applications with more severe requirements for mechanical properties, it is important to study the influence of process parameters and subsequent heat treatment on the mechanical behavior. In order to characterize the boron steel DIN 39MnCrB6-2, the metastable phase diagram and the hot ductility curve were built. The influence of tempering temperature on the microstructure and mechanical properties of tensile and impact strength was studied.For this study, DIN 39MnCrB6-2 rolled steel bars samples were used. They were provided by Gerdau -Specialty Steel Brazil Pindamonhangaba -SP. The samples could be divided into two different diameters and cross sections: square 155 mm (G1) and round 34.93 mm (G2), from sequential steps of manufacturing process. These samples were quenched and tempered and the tensile mechanical properties, impact resistance (Charpy V-notch) and hardness were analyzed. These samples were also characterized by optical microscopy and scanning electron microscopy. Samples from the first step of rolling mill (square 155 mm)were used for chemical analysis to identify the segregation pattern and also to hot ductility tests. In samples G1 it was observed inverse segregation of carbon and no abnormal ductility loss in hot ductility test. Impact resistance results showed low absorbed energy for all tempering temperatures. Microscopy observation showed coarse borocarbides. Samples G2 showed significant differences in tensile properties and hardness related to tempering temperature. However, no significant differences in impact resistance (CVN) at low test temperatures (-40 ° C) were observed. Microscopy observation showed thin borocarbides.It was concluded that the formation of borocarbides is inherent in boron steels and their coarse morphology should be avoided in order to reduce embrittlement. Borocarbide morphology control is more effective to improve impact resistance than reduction ratio.

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Crystallography of M23C6 and M6C precipitated in a low alloy steel

Cited by 64 publications

References 8 publications

Ridging Control in Transformable Ferritic Stainless Steels

Ridging Control in Transformable Ferritic Stainless Steels

A Eutectoid Reaction for the Decomposition of Austenite into Pearlitic Lamellae of Ferrite and M23C6 Carbide in a Mn-Al Steel

Produção e caracterização de barras laminadas do aço ao boro DIN 39MnCrB6-2

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