Steel Authority of India

About: Steel Authority of India is a based out in . It is known for research contribution in the topics: Microstructure & Ultimate tensile strength. The organization has 797 authors who have published 661 publications receiving 9958 citations. The organization is also known as: SAIL.

Prediction of Slag Pool Thickness in Continuous Casting Mould

Abstract: Physical properties of mould powder control the surface equality of the continuously cast products. Formation of mould slag of specific quality in caster mould requires correct formulation of melting rate property so that molten slag of adequate thickness is continuously generated. The melting of the casting powder, apart from mineralogical composition, is influenced by caster application conditions such as casting speed, oscillation parameters etc. The known melting rate tests are not amenable for quantitative prediction of slag pool thickness since they do not consider all the application conditions together. Present work describes a methodology predicting slag pool thickness based on melting rate measurements using various known experimental techniques. The measured melting rate data has been combined to generate acceleration coefficients incorporating effect of slag consumption and mould oscillation on powder melting. An effective melting rate parameter (EMR) has been formulated using these coefficients. Measured slag pool thickness (d ) during actual casting correlates well with the defined EMR in the speed range of 0.55 to 1.5 m/min.d=35.70·EMR·V/(a·b)+2.1, R2=0.94 The high confidence level of this correlation indicates applicability of effective melting rate parameter (EMR) concept for prediction of slag pool thickness.

A mixture of experts approach towards intelligibility classification of pathological speech

Abstract: Pathological speech involves atypical speech production which may result from several factors including oral diseases, physical disabilities in the voice production system and atypical anatomy. Automatic evaluation of intelligibility in patients with pathological speech can assist accurate diagnosis of pathological conditions. Loss of intelligibility may be associated with one of the several pathological conditions, making automatic evaluation a challenging computational problem. A Mixture of Experts (MoE) models class boundaries using a weighted combination of several experts and can characterize the complex class boundaries arising due to pathological variability. We train an MoE for intelligibility evaluation using a modified Expectation Maximization (EM) algorithm based on joint simulated annealing-gradient ascent procedure. Our algorithm optimizes the expert parameters and simultaneously obtains the feature subsets for each expert. We observe that the MoE trained using the new EM algorithm not only outperforms a single classifier baseline but also the vanilla MoE. We perform further data analysis and interpret the weights assigned to each expert during inference. Also, we obtain a different feature subset per expert in the mixture. This illustrates feature use based on location of the data point in the feature space.

Evaluation of Dust Generated from Basic Oxygen Furnace Steel Making

Abstract: A detailed characterization has been made of the dust generated during steel making in basic oxygen furnaces (BOF). Chemical composition and particle size distribution have been analyzed. X-ray diffraction, scanning electron microscopy, and electron probe micro-analysis techniques have been used to identify the morphology and the nature of the major iron-bearing phases as well as the gangue constituents. The dust characteristics have been found to be widely different, depending on the type of process used in BOF steel making, namely, suppressed combustion or total combustion. The type of dust abatement system (dry or wet) additionally influences the nature of the gangue constituents. The possibility of utilizing the iron-bearing major phases has been examined.

Effect of carbides on the austenite grain growth characteristics in 1Cr-1C and 6Cr-1Mo-1C steels

Abstract: The nature of carbidesvis-a-vis austenite grain growth characteristics in a ball-bearing steel (1Cr-1C) and in a wear-resistant steel (6Cr-1Mo-1C) is reported. Quantitative EPMA analysis was used to determine the type of carbides andin situ examination of austenite grain growth was carried out in a hot-stage microscope. The grain size against temperature plots indicated an initial stage of slower “normal” grain growth, followed by the “abnormal” growth, or, grain coarsening beyond a critical soaking temperature. The M3C type of carbides containing a small amount of chromium could inhibit grain coarsening up to 1223 K in 1Cr-1C steel, whereas the alloy carbides of the M7C3 type with a substantial amount (about 35 mass%) of chromium were more effective in restricting grain growth even up to 1273 K in the 6Cr-1Mo-1C steel. In addition, the grain sizes obtained in the latter steel were found to be considerably smaller than those of the former variety at all soaking temperatures investigated.