摘要:

Equilibria between CaO‐TiOxor CaO‐Al2O3‐TiOxmelts and liquid iron with respect to O, N and S were studied at 1873 K as a function of Ti (or Al) content in metal, using a CaO or an Al2O3crucible. The Al‐O and Ti‐O relations in liquid iron were studied, and nitride and sulfide capacities defined byand, respectively, were obtained from nitrogen and sulfur distribution ratios, coupled with the analyzed oxygen content in liquid iron or the PO2determined by Ti/TiO2equilibrium. Based on these results, activities of Al2O3and activity coefficients of TiO2and TiO1.5were evaluated.

ISSN:0003-8962    

DOI:10.1002/srin.199401068

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Water model studies have been conducted to characterise the flow conditions in continuous casting tundishes under conditions of open and submerged nozzles. In this investigation simulations of practical problems of flow interruptions from the ladle, thermal inversions due to uninsulated ladle, and pneumatic agitation near the tundish end wall were conducted.The studies showed that incorporation of suitable flow control devices brings about homogenisation of temperature and composition between strands in the above cases. This study also showed that agitation of the liquid at the end wall reduces the extent of stagnant zone in the tundish.

ISSN:0003-8962    

DOI:10.1002/srin.199401069

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

A mathematical, two‐dimensional model for the analysis of the temperature and solidification behaviour in the substrate and deposit for the spray forming process of metals has been developed. Due to the irregular shape of the growing deposit, which changes with spraying time, a grid transformation method was successfully developed for the calculation of the temperature distribution and solidification front in the growing deposit. The influence of process parameters, i.e. thermal conditions of the metal spray at impact, heat transfer coefficient at the surface of the deposit and geometrical parameters, are qualitatively and quantitatively discussed.

ISSN:0003-8962    

DOI:10.1002/srin.199401070

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

With a near‐net‐shape continuous‐casting simulator and the hot deformation simulator Wumsi, laboratory simulation tests have been performed to determine the final microstructure and the mechanical properties of a Ti‐microalloyed low carbon steel for cold forming, produced in the process of direct charging of thin slabs. For two initial specimen thicknesses (45 and 25mm) restricted values of total strain ϕ∑were available to improve the coarse as‐cast microstructure. In a series of deformation schedules ϕ∑was divided systematically into two components: an austenite grain‐refining strain ϕγ–GF(above the recrystallization‐stop‐temperatureTRS) and an austenite strengthening strain ϕγ–s(belowTRS). After hot deformation accelerated cooling with simulated coiling was employed. It was found that the direct charging process guarantees a more complete dissolution of Ti(C,N) and so an intensifying effect of Ti‐microalloying in comparison to a conventional cold charging. Structure refinement by rolling performed predominantly in the temperature region of non‐recrystallized austenite (increasing ϕγ–s) leads to better hot strip strength and improved low temperature toughness properties accompanied with a slight deterioration of uniform elongation.

ISSN:0003-8962    

DOI:10.1002/srin.199401071

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

The simulation of metal forming processes with the finite element method (FEM) is becoming more and more significant for process analysis and optimising. With regard to the quality of the calculations care must be taken to select a suitable FE model. Possibilities for FEM applications will be shown using the examples of die bending sheets and profile bending. A practical extension of this application is the support of the FE systems user by access to a material database.

ISSN:0003-8962    

DOI:10.1002/srin.199401072

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

The crystallographic orientation distribution of cold rolled and recrystallized low‐carbon deep drawing steel is quantitatively investigated by means of the series expansion method and the technique of model component fit. The results of both methods are utilized to describe the elastic properties of the inspected sheets. The application of the model components allows a very good approximation of the course of Young's modulus and corresponds to experimental results as well as to the predictions stemming from the series expansion method. In addition to the influence of peak‐type texture components also the impact of complete and incomplete fibre‐type texture components on the course of Young's modulus is inspected.

ISSN:0003-8962    

DOI:10.1002/srin.199401073

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

The extent and degree of dispersion of carbonitrides in high strength low alloy (HSLA) steels is controlled by nucleation and growth processes. A thermodynamic model is presented enabling calculation of the composition of the carbonitride embryo as well as the chemical driving force for nucleation (CDF) in the austenite region of a multicomponent microalloyed steel. The analysis made for a Nb‐Ti HSLA steel indicates that the critical carbonitride nucleus is richer in N and Ti than the bulk precipitate at equilibrium at a given temperature and the difference increases when the holding temperature decreases. The results also show that the Ti addition has an optimum value defined by the maximum in the ratio of bound Ti and Nb to their total content. The maximum CDF correlated with the minimum Ti content sufficient to form a carbonitride at the austenitizing temperature.

ISSN:0003-8962    

DOI:10.1002/srin.199401074

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

The fractal dimension along the crack propagation direction on the fatigue fracture surface of a dual‐phase steel was investigated by both vertical section profile method and secondary electron line scanning method. Results from the vertical section profile method showed that during the crack propagation, the fractal dimension of the fracture surface increases with increasing stress intensity factor, however, the secondary electron line scanning method presented somewhat different results of fractal dimension and was proved not feasible in all kinds of fracture surfaces, so this method is not suggested in calculating the fractal dimension of the fracture surface.

ISSN:0003-8962    

DOI:10.1002/srin.199401075

出版商:Wiley    

年代:2016

数据来源: WILEY