摘要:

Two‐probe conductivity measurements made forM3P2O8(M= Ca, Ba) suggested that the electrical conduction of these phosphates would primarily be due to the migration of Ca2+and Ba2+ions. At relatively low temperatures and high oxygen partial pressures, in contrast to Ca3P2O8, however, Ba3P2O8shows partial electronic conduction.

ISSN:0003-8962    

DOI:10.1002/srin.199100422

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Titanium nitride in microalloyed steels can be formed already in delta iron, as can be shown by thermodynamical calculations basing on measurements of the solubility in austenite or in the melt. The solubility products calculated with respect to delta iron differ up to one order of magnitude. Therefore, between 1420 and 1510°C a direct measurement was performed on pure Fe–Ti–N alloys yielding a solubility product (related to the composition TiN1,0) of logLTiNα/δ= −17205/T+ 5.56. It is identical with that one calculated from the solubility in liquid iron.The differing results of calculations basing on the solubility in austenite are attributed to incorrect data of the Gibbs free solution energy of titanium in austenite. Starting from the present measurements and from the data reported with respect to pure titanium and to the nitrogen solubility a Gibbs free solution energyGTi,γH(x)– GTi,γR= −40294 − 13.66.T[J/mole] was deduced which is more negative than previous data.

ISSN:0003-8962    

DOI:10.1002/srin.199100423

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

A mathematical model to predict steel bar thermal behaviour during continuous quenching after the finishing mill has been developed. The model includes process variables, such as finishing rolling speed, finishing temperature, rod size and chemical composition, water flowrate and mechanical design of the cooling device. It was found that empirical correlations for the heat‐transfer coefficient belonging to water spray systems are suitable to simulate fast cooling employing submerged water‐cooling tubes. Martensite depth is strongly influenced by the bar diameter and water velocity inside the submerged tube. Mist spray systems are not as effective as submerged tubes for cooling steel bars, although, the initial cooling rates are higher. The % volume of martensite is a direct function of the self‐tempering temperature, and independent of the fast cooling device.

ISSN:0003-8962    

DOI:10.1002/srin.199100424

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

New possibilities for the application‐oriented modelling of hot yield strength are developed on the basis of well‐known and well‐established model concepts of the plastic behaviour of metallic materials. The suggested method describes the flow behaviour as a complex macroscopic process. Unlike the usual phenomenological approaches, the yield strength can be calculated more accurately, the typical appearance of hot yield curves being adequately registered from the beginning of deformation to the exhaustion of plasticity. Furthermore, better consideration of metallo‐physical aspects is made possible.

ISSN:0003-8962    

DOI:10.1002/srin.199100425

出版商:Wiley    

年代:2016

数据来源: WILEY

ISSN:0003-8962    

DOI:10.1002/srin.199100426

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

In this paper results of the influence of the material flow on the microstructural evolution of austenite during hot flat rolling are presented. Material flow is investigated by means of rolled specimens, which are prepared with a square‐grid in the middle of the plate. Analyses of the microstructure were applied to elucidate the evolution of the prior austenite structure in thickness direction of the rolled specimens. The inhomogeneous deformation in thickness direction in combination with algorithms for the calculation of the microstructural evolution gives more detailed information on the occurrence of microstructural inhomogeneities compared to the usually applied strip‐model.The inhomogeneous deformation over the thickness of a rolled sheet can be described with sufficient accuracy by means of the strain model according to Zouhar and Lachmann.

ISSN:0003-8962    

DOI:10.1002/srin.199100427

出版商:Wiley    

年代:2016

数据来源: WILEY

ISSN:0003-8962    

DOI:10.1002/srin.199100428

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

The precipitation strengthening of modified chromium steels is effected predominantly by M23C6carbides. In molybdenum‐modified 9% chromium steels, creep resistance depends on the dispersion of the M23C6carbides and on the molybdenum content in the solid solution. There is no point in increasing molybdenum contents of molybdenum‐modified steels above approximately 1 wt.%. In vanadium‐modified steels precipitation strengthening is effected both by M23C6carbides and by VCxNycarbonitrides. If the amount of nitrogen in solid solution is insufficient, this reduces the volume fraction of VCxNyin the structure and thus impairs the creep resistance of the steel. It is advisable to restrict the aluminium and titanium contents in the vanadium‐modified chromium steels.

ISSN:0003-8962    

DOI:10.1002/srin.199100429

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Das Dauerschwingverhalten des Stahles X 2 CrNiMoN 22 5 3 (Werkstoff‐Nr. 1.4462) bei Raumtemperatur wurde sowohl an Luft als auch in 3%iger NaCl‐Lösung bei reiner Zug‐Schwell‐Beanspruchung mit einer Prüffrequenz von 25 Hz untersucht. Für glatte Proben wurde hierbei an Luft die reine Zug‐Schwellfestigkeit von 490 N/mm2ermittelt. Bei korrosiver Belastung betrug die Zeitschwingfestigkeit fürN= 107nur noch 78 % des Wertes an Luft, wobei auch bei noch höheren Schwingspielzahlen mit Probenbrüchen gerechnet werden muß. Vergleichende Untersuchungen an gekerbten Proben ergaben, daß der gewählte Kerbfaktor von 2,0 sowohl für die Versuche an Luft als auch in 3%iger NaCl‐Lösung zu einem Absinken der dynamischen Festigkeit um 10% führte. Die zusätzlich für glatte Proben an Luft ermittelte reine Zug‐Druck‐Wechselfestigkeit betrug 350 N/mm2.Die Auswertung der bei allen Schwingungsrißkorrosionsuntersuchungen in 3%iger NaCl‐Lösung aufgezeichneten Ruhepotentialverläufe zeigte bei Proben, die aufgrund der geringeren mechanischen Belastung nicht zu Bruch gingen, im gesamten Versuchsverlauf einen kontinuierlichen Potentialanstieg. Bei mechanisch höher belasteten Proben dagegen kündigte sich der Probenbruch etwa 105Schwingspiele vorher durch stark progressive Negativverschiebung des Potentials an.

ISSN:0003-8962    

DOI:10.1002/srin.199100430

出版商:Wiley    

年代:2016

数据来源: WILEY

ISSN:0003-8962    

DOI:10.1002/srin.199100431

出版商:Wiley    

年代:2016

数据来源: WILEY