1. |
Comments on the activity of carbon in liquid iron |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 125-127
Nev A. Gokcen,
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摘要:
Existing data on the activity of carbon in liquid iron have been critically assessed and interpreted by using new equations derived by the author. These equations are the standard Gibbs energy of melting of graphite, the graphite‐liquid iron saturation equation, and the interrelationship in the Margules equation. The resulting equation isg2= 130,330 ‐ 32.19T‐ (108,330 ‐ 15.47 7)x12‐ (344,000 ‐ 220.4 T)x12x2+ (512,500 ‐ 380.3 7)x12x22whereg2is the partial excess Gibbs energy of dissolved carbon in J/mol,Tis the temperature in K, andx1andx2are the mole fractions of iron and carbon in the melt, respectively.g2refers to graphite as the standard state so thatg2=R TIn γ2= ‐R Tlnx2(at graphite saturation), whereRis the gas constant, and γ2is the activity coefficient. From the preceding equation,g1for iron has been obtained.
ISSN:0003-8962
DOI:10.1002/srin.199400940
出版商:Wiley
年代:2016
数据来源: WILEY
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2. |
The 3‐dimensional structure of macrosegregation in continuously cast high‐carbon steel |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 128-131
Trevor B. Abbott,
Ian B. Hoyle,
A. Stephen Woodyatt,
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摘要:
Three‐dimensional segregation maps were obtained by serially sectioning rolled billets of high carbon steel. The sections were macroetched to reveal phosphorus segregation then digitised and combined using a computer. Volume rendering software was used to create images that represented views of continuously cast blooms with unsegregated steel transparent and macrosegregation opaque. The images showed the overall V‐structure of macrosegregation and channel like morphology of individual macrosegregates. Samples with a fully columnar structure and a mixed columnar‐equiaxed structure were compared. A large equiaxed zone disperses the macrosegregation over a wider area and increases the angle and length of channels. The observed structures suggest that macrosegregation forms through a combination of internal hot tearing and erosion of solid by flowing segregated liquid.
ISSN:0003-8962
DOI:10.1002/srin.199400941
出版商:Wiley
年代:2016
数据来源: WILEY
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3. |
Cavitation behaviour of a metastable Cr‐Mn‐austenite |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 132-137
Isabella‐Marie Zylla,
Hans Paul Hougardy,
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摘要:
The microstructures of three steels with metastable austenite with mass contents of 10‐14 % Cr, 10‐15 % Mn and O.1‐0.35 % C were optimized by a simulation of the cavitation load. Results of cavitation tests show that the microstructure should be fine grained, to avoid the arise of cracks in the early stages. The materials were pretreated by a thermomechanical treatment. Criteria for a selection were the mechanical properties and the microstructure. According to the results a steel with mass contents of 13 % Cr, 10 % Mn and O.35 % C (X 35 CrMn 13 10) should have the best cavitation resistance. In this steel a deformation of 400 °C produces a dislocation network that forces a transformation of austenite to very fine martensite plates during cavitation and gives a smooth abrasion. The cavitation resistance of steel X 35 CrMn 13 10 in a pretreated condition is in the range of published values of a Steinte 6B, but the production of the steel is more versatile and less expensive than that of a Stellite.
ISSN:0003-8962
DOI:10.1002/srin.199400942
出版商:Wiley
年代:2016
数据来源: WILEY
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4. |
Evolution of acicular ferritic microstructure in a titanium bearing HSLA steel |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 138-145
Subrata Chatterjee,
Nirmalendu S. Mishra,
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摘要:
An attempt has been made to design and develop acicular ferritic steels by adopting three‐stage controlled rolling, with titanium alone as microadditive. Process parameters such as finish rolling temperature (FRT), amount of deformation during the last pass and also the cooling rate after finishing have been altered to obtain different microstructural effects. Optical as well as transmission electron microscopy studies indicated that acicular ferritic microstructure can be engendered by applying a minimum deformation of 25 % at the finishing pass followed by water quenching. Decreasing the FRT from 850 °C, for water quenched steels deformed 33 %, resulted in the refinement of polygonal ferrite, whereas the reverse is the case with the aspect ratio of acicular ferrite. The volume fraction of acicular ferrite progressively increases as the FRT is lowered. Evaluation of tensile properties suggested that yield strength as high as ~ 600 MPa with an elongation of ~ 25 %, could be obtained by finishing at a lower temperature of 750 °C. An impact transition temperature (ITT) of ‐53 °C indicated that the steel possesses adequate toughness properties. As weldability is one of the criteria for structural applications, this aspect too has been investigated.
ISSN:0003-8962
DOI:10.1002/srin.199400943
出版商:Wiley
年代:2016
数据来源: WILEY
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5. |
Influence of heat transfer on the development of residual stresses in quenched steel cylinders |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 146-151
Axel Majorek,
Berthold Scholtes,
Hermann Müller,
Eckard Macherauch,
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摘要:
In this paper results of systematic FE‐calculations about the influence of characteristic points of the temperature dependent heat transfer coefficient, especially the Leidenfrost point and the point of maximum heat transfer coefficient on the development of residual stresses are discussed. The numerical investigations were carried out for SAE 1045 and 4140 steel cylinders with 10 and 20 mm 0 quenched in water and oil, respectively. In this work experimentally determinedh, T‐curves are linearly approximated in the successive stages of heat transfer. Changes of the Leidenfrost‐temperature do not influence the middle plane residual stresses of the cylinders investigated. Increasing maximum heat transfer coefficients and low temperatures of maximum heat transfer coefficient, respectively, cause higher magnitudes of residual stress. The development of residual stresses is determined by the temperature dependent gradient of the heat flux densityδq/δTin the temperature range of martensitic transformation. Increasing Leidenfrost‐temperatures cause more homogeneous stress and residual stress states at the surface of quenched cylinders due to the symmetrical cooling of the sample in axial as well as in radial direction. In particular, it was shown that during immersion cooling of cylindrical parts the heat transfer is locally dependent. Simulating immersion cooling this dependence has to be considered using effective local heat transfer coefficients.
ISSN:0003-8962
DOI:10.1002/srin.199400944
出版商:Wiley
年代:2016
数据来源: WILEY
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6. |
Prediction of creep of metallic materials under time‐variable temperatures and stresses |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 152-156
Nikolaos D. Batsoulas,
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摘要:
A method is presented for the prediction of metallic materials creep behaviour at time‐variable temperatures, exclusively with creep input data under constant loading. The method is derived from a more general physical‐phenomenological model and, additionally, incorporates the prediction under time‐variable stresses. To test the method's predicting capability, a series of experiments was carried out for the creep strain at time‐variable temperatures and stresses for austenitic steel X8CrNiMoNb 16‐16. The test data were predicted reasonably well using the method in question.
ISSN:0003-8962
DOI:10.1002/srin.199400945
出版商:Wiley
年代:2016
数据来源: WILEY
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7. |
Mechanical properties of Mg‐Mg2Si light‐weight alloys as piston material |
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Archiv für das Eisenhüttenwesen,
Volume 65,
Issue 4,
2016,
Page 157-165
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ISSN:0003-8962
DOI:10.1002/srin.199400946
出版商:Wiley
年代:2016
数据来源: WILEY
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