Behavior of Niobium Carbides and Nitrides in Steel

Mori, Toshisada; Fujita, Kiyohiko; Tokizane, Masaharu; Yamaguchi, Ko

doi:10.2355/tetsutohagane1955.50.6_911

Cited by 20 publications

(10 citation statements)

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“…Balasubramanian et al [57] also acknowledged this fact that some uncertainty still exists in the description of Fe-Nb-C system. But the data from Huang's calculation [51] were consistent with earlier investigations [41][42][43][44][45][46][47][48][49][50] in the same range of temperature (1273 to 1473 K). Lee [52] developed a self-consistent thermodynamic description for the Fe-Nb-Ti-C-N quinary system and on the way reassessed Huang's work [51] on Fe-Nb-C ternary systems in terms of its sub-binary systems i.e.…”

Section: Solubilitysupporting

confidence: 87%

“…There have been many experimental determinations as well as thermodynamic predictions of the solubility of niobium carbide precipitates in ternary Fe-Nb-C austenite [41][42][43][44][45][46][47][48][49][50]. The results have been reviewed over time and sometimes reassessed to provide a more suitable thermodynamic description of NbC solubility in austenite [39,40,[49][50][51][52].…”

Section: Description Of Niobium Carbide Solubility Inmentioning

confidence: 99%

“…A solubility-minimum was observed (around 0.4-0.5 wt% C) at 1273-1473 K. This was attributed to the strong solute interactions in austenite and non-stoichiometry of the carbides. It was argued that earlier investigations [41][42][43][44][45][46][47][48][49][50] were performed at low-carbon concentrations (below 0.2 wt%) without addressing the solute interactions and carbide non-stoichiometry and hence are not capable of predicting the solubility at higher carbon levels where the effects of solute interactions become significant. The classical solubility product expression (equation 2.4) was modified by incorporating an additional term for the concentration dependence on carbon [40].…”

Section: Description Of Niobium Carbide Solubility Inmentioning

confidence: 99%

See 2 more Smart Citations

Niobium in Microalloyed Rail Steels

Ray

Bhadeshia

2015

HSLA Steels 2015, Microalloying 2015 &Amp; Offshore Engineering Steels 2015

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Rail steels rely primarily on possessing adequate wear and rolling contact fatigue resistance. These properties, together with the toughness, can in principle be optimized by implementing thermomechanical processing assisted by controlled niobium additions. The purpose of the current work is to develop a Nb-microalloying strategy in the context of high-carbon pearlitic and cementite-free bainitic steels. The conventional methods do not leave the critical regions of a rail section in a suitably processed state. An attempt has been made for the first time, to create a pancaked austenite grain structure, with an examination of the consequences on the final Declaration This dissertation is submitted for the degree of Doctor of Philosophy at the University of Cambridge. The research reported was conducted under the supervision of

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Section: Solubilitysupporting

confidence: 87%

Section: Description Of Niobium Carbide Solubility Inmentioning

confidence: 99%

Section: Description Of Niobium Carbide Solubility Inmentioning

confidence: 99%

See 1 more Smart Citation

Niobium in Microalloyed Rail Steels

Ray

Bhadeshia

2015

HSLA Steels 2015, Microalloying 2015 &Amp; Offshore Engineering Steels 2015

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“…Nb 4,8,9) ，Ti 10) Table 3 に示す。 Fig.13 に示すが，計算値と実測値(Fig.6) は良好な一致を示す。このことから，鋼内部への炭素の拡散は(5)式に従って起こっており，炭素濃度分布の異常低下現象は Cs の異常低下によって起こっていることがわかる。次に，浸炭中どの時間で Cs が低下したのかを検討し Fig. 12.…”

Section: 抑制する必要がある。結晶粒粗大化を抑制するためには，unclassified

Abnormal Low Surface Carbon Concentration in Gas Carburized Nb-Bearing Case Hardening Steel after Severe Machining

Eto¹,

Umemoto²,

Sasaki³

et al. 2013

Tetsu-to-Hagane

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緒論The surface carbon concentration (Cs) of carburized Nb-bearing steel (SCM420Nb) was found to decrease substantially when carburized after severe machining. It was observed that the effect of machining condition is small in normal case hardening steel (SCM420), in which the Cs was in the range of 0.9~1.1%. However, the Cs in carburized SCM420Nb was reduced to 0.61% by mild machining, and 0.38% by severe machining. Since the Cs of severely machined SCM420Nb recovered to > 0.8% after the removal of surface layer by polishing, it was concluded that the abnormal decrease in Cs of SCM420Nb is mainly due to severely deformed surface layer produced by machining. Discussion was made on the abnormally low Cs observed in severely machined SCM420Nb steel with regard to the effect of solute Nb on the carbon activity and the effect of surface roughness. It was found that these effects are small compared with the observed reduction in Cs. Comparing the experimental and calculated carbon concentration profiles, Cs was expected to be reduced immediately after the start of carburizing. Finally, it was proposed that the oxide layer created on the surface during carburizing might be the cause of the abnormally low Cs.

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“…Mechanical isolation with an ultrasonic "jack hammer" (173) and chemical isolation by chlorination (228,279,528) , bromination (355), selective dissolution techniques (56, 234,360,387,415,446,528), and electrochemical approaches (48, 233, 234,260,289,290,299,406,435,575) were used for the isolation of various nonmetallic inclusions and for the separation of austenite and martensite.…”

Section: Nonmetallic Compoundsmentioning

confidence: 99%

Ferrous metallurgy

Pásztor¹,

Hines²

1967

Anal. Chem.

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HIS REPORT reviews the advances in T ferrous metallurgical analysis from October 1964 to December 1966. As in the past (58), it draws extensively from abstracts and is not intended to be a complete compilation of the papers published in the field.The increased use of fast steelmaking, processes, vacuum deoxidation, and continuous casting techniques has greatly influenced the need for rapid and automated ferrous nietallurgical analytical methods (14). In addition, stringent requirements on steel composition by steel users have forced the analytical chemist to search not only for rapid, but also for more accurate analytical methods. The majority of methods found in the literature still involve modifications of well established techniques and procedures rather than the introduction of new approaches.Greatest progress was made in the application of atomic absorption spectrometry (502) and neutron activation techniques (335, 557) to the routine analysis of iron, iron ores, slags, and steels, and in the automation and computerization (166) of chemical and instrumental methods.Present steel sampling and sample preparation techniques are generally too sloiv and inadequate for control of the new steelmaking processes and thus present the most apparent restriction to the rapid analytical methods. The realization of this problem was indicated by the relatively large number of papers published on sampling (95,428, 429,480, 605, 51 1 , 520) and on attempts for the direct analysis of molten steel (32,Emission and x-ray spectrometric, atomic absorption spectrophotometric, and other instrumental techniques with various degrees of automation became the most important means for better process and quality control. Chemical routine methods, even the automated ones, decreased in importance except in the field of nonmetallic inclusion isolation where there is a new renaissance in the use of chemical approaches (10,293,381).Schemes were given for the analyses of cast iron (484) and slags (288,417).Differential spectrophotometry (522) , electrochemical methods (380), atomic absorption spectrophotometry (502), gases in metals analysis (42, 214,242,265,364), and standard deviation of methods (132) in connection with steel analysis were reviewed. 158-161, 344, 366, 567). ALUMINUM Volumetric aluminum procedures involved variations of EDTA (156, 257, 331), bromatometric (440), and potentiometric (134) titrations. Xodifications of the 8-hydroxyquinoline (81 , I l Z ) , aluminon (120, 448, 487), eriochrome cyanin R (220, 22$), solochrome cyanine (411)) chrome azurol S (69, 77, 4 Z l ) , and alizarin red S calcium (106) spectrophotometric and of the 8-hydroxyquinoline spectrofluorometric (20300) methods were described. Most pro-cedures involved preliminary separations by mercury cathode (109, 200, +$do), solvent extraction (69, 212, 120, 200,309,411,448), precipitation (goo, 25'7), or ion exchange (509). 135,Aluminum was polarographically determined in stainless steel (4437, ferrotitanium (199)) and ferro-niobium (198). Neutron activation an...

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Behavior of Niobium Carbides and Nitrides in Steel

Cited by 20 publications

References 1 publication

Niobium in Microalloyed Rail Steels

Niobium in Microalloyed Rail Steels

Abnormal Low Surface Carbon Concentration in Gas Carburized Nb-Bearing Case Hardening Steel after Severe Machining

Ferrous metallurgy

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