Process In Steel Industry Research Articles

Influence of the Impact Angle and the Gravity Direction on Heat Transfer during the Cooling of a Cylinder by a Free Planar Subcooled Impinging Jet

Cooling from impinging jet is nearly compulsory in steel industry processing especially in Run Out Table processing and steel tubes production because of the high heat transfer rates provided by the boiling of the subcooled water jet. As far as metallurgical phase transformations, residual stresses and deformations in the workpiece are concerned, the temperature drop during cooling must be perfectly controlled thanks to a fully understanding of the heat transfer mechanisms. In a previous study [1] the effect of surface to jet velocity ratio on heat transfer has been characterized and it has been shown that this parameter has a significant influence on shoulder of flux collapse. In order to understand the effect of more industrial quench process parameters, an innovative experimental quenching device has been designed and built. It allowed us to make heat transfer measurements at the surface of a hot nickel cylinder impinged by a subcooled water jet, according to several angles of impact and three jet directions against gravity. The results clearly highlight an effect of these two parameters on the heat transfer mechanisms at the surface of the tube. These results allow a better understanding of the origins of temperature heterogeneities inside the tube during the quench.

横型遠心鋳造と縦型遠心鋳造の液相挙動の違い

A centrifugal casting method is a key technology for producing high quality rolls which are used in a rolling process in steel industry. Because the surface quality of steel products highly depends on the roll quality and it is affected by liquid motion in the centrifugal casting method, control of the liquid motion is essential for supply of defect free rolls to the steel industry. In this research, liquid flow in the centrifugal casting method has been numerically calculated for clarification of difference of liquid motion in a horizontal type centrifugal casting method and a vertical one. The mainly obtained results are as follows. The center of the gravity periodically oscillates and its cycle is longer than the rotation cycle of the mold in the both cases of the horizontal and vertical types. Its time average in the horizontal type locates above the center axis of the mold while that in the vertical type is the same with the center axis. Increase in apparent viscosity in the vicinity of the mold wall accelerates the damping of the oscillating motion of the center of the gravity.

A bottom-up model to estimate the energy efficiency improvement and CO2 emission reduction potentials in the Chinese iron and steel industry

China's annual crude steel production in 2010 was 638.7 Mt accounting for nearly half of the world's annual crude steel production in the same year. Around 461 TWh of electricity and 14,872 PJ of fuel were consumed to produce this quantity of steel. We identified and analyzed 23 energy efficiency technologies and measures applicable to the processes in China's iron and steel industry. Using a bottom-up electricity CSC (Conservation Supply Curve) model, the cumulative cost-effective electricity savings potential for the Chinese iron and steel industry for 2010–2030 is estimated to be 251 TWh, and the total technical electricity saving potential is 416 TWh. The CO2 emissions reduction associated with cost-effective electricity savings is 139 Mt CO2 and the CO2 emission reduction associated with technical electricity saving potential is 237 Mt CO2. The FCSC (Fuel CSC) model for the Chinese iron and steel industry shows cumulative cost-effective fuel savings potential of 11,999 PJ, and the total technical fuel saving potential is 12,139. The CO2 emissions reduction associated with cost-effective and technical fuel savings is 1191 Mt CO2 and 1205 Mt CO2, respectively. In addition, a sensitivity analysis with respect to the discount rate used is conducted.

Research on Energy Consumption Analysis Method Based on Improved Fuzzy Analytic Hierarchy Process (FAHP) in Iron and Steel Industry

The relations between production process and energy consumption are made an in-depth application analysis and theory study with theory of systematic energy-saving , technique of intelligence analysis and optimization based on the background of study on energy-saving and reduce energy consumption. Making intensive research on theories of systematic energy-saving and analyzed with function mechanism and quantitative relation of the main production system, auxiliary production system and energy conversion system. It put forward the energy flow direction and energy consumption in each production process and the influence of material flow on energy consumption in iron and steel industry. The sequence of all kinds of material influence comprehensive energy consumption per ton steel and energy quantitative target of all factors influence energy consumption are worked out with improved fuzzy AHP(Analytic Hierarchy Process) which study of comprehensive energy consumption in typical iron and steel production process from the point of system. It has great immediate significance to guide drawing the scientific plan of economy-saving and reduce energy consumption in iron and steel industry

Cooling of a Rotating Cylinder by a Subcooled Planar Jet - Influence of the Surface Velocity on Boiling Regime

Cooling from impinging jet is nearly compulsory in steel industry processing especially in Run Out Table processing and steel tube production because of the high heat transfer provided by the boiling of the subcooled water jet. As far as metallurgical phase transformations, residual stresses and deformations in the workpiece are concerned, the temperature drop during cooling must be controlled thanks to a full understanding of the heat transfer mechanisms. One of the main characteristic using jet impingement is that the transition boiling regime may exist for very high superheat and thus the Leidenfrost temperature is higher than in pool boiling; consequently, boiling curves generally have a particular shape in the transition boiling regime which is usually called “shoulder of flux”. In this study, an innovative experimental quenching device has been used for analyzing the effect of the wall velocity of the surface to be cooled on the boiling curves (i.e. heat transfer) and we especially point out that the “shoulder of flux” (i.e. transition boiling regime) is strongly dependent on the surface to jet velocity ratio (r*). We found that a very small increase of the wall velocity has a high influence on shoulder of flux collapse.

Automated visual classification of frequent defects in flat steel coils

Surface inspection is one of the most important facets of quality-control systems in the steel manufacturing and processing industry. A number of surface defects can be detected by a visual inspection. However, human visual inspection becomes a hard task due to the high-processing speed. In the present paper, the automated visual inspection of flat steel is approached. A detailed description is given of the main aspects involved, concerning image acquisition, image processing algorithms, architecture design, the custom software developed, and data transmission and synchronization. Particular attention is paid to feature extraction and classification. Six kinds of defects are finely classified: weld, white rust, transporter marks, pitting corrosion, protuberance of zinc, and rolled marks. The proposed solution has been implemented and tested in a real industrial environment, in a flat steel cutting factory, showing suitable results. A successful classification ratio of about 87% of the known defects has been obtained, which is considered a reliable result.

An Impedance Identification Approach to Sensitive Detection and Location of Stator Turn-to-Turn Faults in a Closed-Loop Multiple-Motor Drive

A single closed-loop inverter drive with multiple motors connected to it is a type of drive topology commonly used in steel processing industry, electric railway systems, and electric vehicles. However, condition monitoring for this type of drive configuration remains largely unexplored. This paper proposes an impedance identification approach to detect and locate the stator turn-to-turn fault in a multiple-motor drive system. Sensitive and fast fault detection is achieved by utilizing the characteristics of current regulators in the motor controller. Experimental results show that the proposed method can reliably detect and locate the stator turn fault on two shaft-coupled 5-hp induction machines under different operating conditions and fault levels with no need of any machine parameters. Although originally developed for multiple-motor drives, the detection scheme can also be directly applied to most of the conventional closed-loop induction motor drives.

Forming of C45 Steel at Critical Temperature

An important measure in steel processing industry is achieving the required mechanical properties and micro structure of the material. A new phenomenon has been discovered recently which allows to refine ferrite grain significantly and to spheroidise carbides over a very short time compared to conventional heat treatment techniques. The newly developed technology based on the ASR (Accelerated Spheroidisation and Refinement) effect consists in heating a steel workpiece through thickness to a temperature no higher than Ac1 and in subsequent plastic deformation. The energy introduced through plastic deformation causes the workpiece temperature to increase. This temperature increase, however, is not uniform throughout the workpiece cross-section, leading to substantial inhomogeneity. Fully austenitized regions, partially austenitized regions, and areas where no phase transformation occurred, coexist. In locations previously subjected to intensive plastic deformation, cementite lamellae disintegrate and globular carbides form. In regions subjected to milder plastic deformation, spheroidisation does not occur directly in the course of the thermomechanical treatment. Despite, the cementite lamellae show a stronger tendency to spheroidise during subsequent annealing. The combination of a suitable pre-heating temperature, an appropriate amount of strain and a possible reheating leads to transformation of initial ferrite-pearlite micro structure with lamellar pearlite into desired ferrite matrix with spheroidised carbides. Key microstructure parameters governing the properties of ferrite-pearlite steels include exactly the ferrite grain size, the distribution of defects within the ferrite grain and the distribution and morphology of carbides. The present article describes a new thermomechanical treatment technique which allows controlling these microstructure parameters and related mechanical properties in order to achieve their favourable combination in structural carbon steel C45. The processing time is very short when compared to several-hour conventional heat treatments. This offers potential for achieving desired mechanical properties with time and energy savings.

A multi‐QMOM framework to describe multi‐component agglomerates in liquid steel

AbstractA variant of the quadrature method of moments (QMOM) for solving multiple population balance equations (PBE) is developed with the objective of application to steel industry processing. During the process of oxygen removal in a steel ladle, a large panel of oxide inclusions may be observed depending on the type of oxygen removal and addition elements. The final quality of the steel can be improved by accurate numerical simulation of the multi‐component precipitation. The model proposed in this article takes into account the interactions between three major aspects of steelmaking modeling, namely fluid dynamics, thermo‐kinetics and population balance. A commercial CFD code is used to predict the liquid steel hydrodynamics, whereas a home‐made thermo‐kinetic code adjusts chemical composition with nucleation and diffusion growth, and finally a set of PBE tracks the evolution of inclusion size with emphasis on particle aggregation. Each PBE is solved by QMOM, the first PBE/QMOM system describing the clusters and each remaining PBE/QMOM system being dedicated to the elementary particles of each inclusion species. It is shown how this coupled model can be used to investigate the cluster size and composition of a particular grade of steel (i.e., Fe‐Al‐Ti‐O). © 2010 American Institute of Chemical Engineers AIChE J, 2010

부분최소자승법과 변수선택을 이용한 코팅두께 예측모델 개발

산업체 공정과정에서 타겟품질변수의 실시간 예측과 관리는 품질제고, 수익율 향상에 중요한 관건이 된다. 본 연구는 내지문강판의 코팅두께를 비파괴적이고 신속한 방법으로 예측하여 균일한 품질의 강판을 생산하기 위해 UV스펙트럼데이터를 이용한 최적예측모델을 개발하고자 한다. 부분최소자승법에서 변수중요도척도를 이용한 변수선택방법은 노이즈성 영역의 독립변수를 줄임으로써 예측정확도는 높일 수 있으며, 스펙트럼데이터의 경우 원데이터보다 적절한 데이터전처리가 예측정확도를 높이는 정보를 제공하기도 한다. 본 연구에서는 부분최소자승법 예측모텔에서 변수선택방법과 데이터전처리효과가 내지문강판 코팅두께 예측정확도 향상에 기여하는 결과를 제공하고, 스펙트럼 데이터를 이용한 품질변수 예측모델 개발 시 적용할 수 있는 일반적인 변수선택방법과정을 제안한다. Coating thickness is one of target variables in quality control process in steel industry. To predict coating thickness and to control quality of anti-fingerprint steel coils, ultraviolet-visible spectra are measured. We propose a variable-interval selection procedure based on the variable importance in projection in partial least square model. Using the proposed variable interval selection method, prediction performance gets better in the reduced model than the full model with full spectra absorbance. It is also shown that the first differencing as a data preprocessing technique does work well for the prediction of coating thickness.

A two-stage scheduling method for hot rolling and its application

Hot rolling scheduling is a difficult problem in the steel processing industry. It involves many objectives and constraints in both technical and practical respects. A two-stage scheduling method is proposed in this paper. Batch planning of staple material is formulated as a VRPTW, which is solved with a modified PGA. Then, batches of the established units are optimized by adjusting rolling sequences using intelligent search algorithms to reach higher hot charge ratios. This method has been applied to a hot strip mill belonging to Baosteel in China. Our results demonstrate that the proposed technique can improve production efficiency and offer significant economic benefits.

Water framework directive - Quality of Corus effluents

A broad range of steel industry liquid effluents have been collected from Corus site discharges for characterisation of their chemical composition, their toxicity to the aquatic environment and their oestrogenicity. This work was done as part of a European funded research project, in order to investigate the potential impacts of the Water Framework Directive on steel industry processes.

A simulation study of despatch bay performance in the steel processing industry

The despatch bay is a critical interface within an organisation, linking the warehousing and transport operations. However, delays here have wider supply chain implications given that the flow of materials through the supply chain is disrupted. Despite this, there has been little research on improvement activities to this process. This paper uses a case study of a steel processor to develop a simulation model to test strategies for increasing despatch bay productivity. From the simulation results, it was found that a combination of improvements were needed, to both reduce process times and ensure the earlier receipt of orders. The research approach presented in this paper can be used in other business environments having similar operating conditions.

Abundance, correlations and spatial patterns of nutrients and metals in till, humus, moss and pine needles in a boreal forest, western Finland

Moss, humus, till and needle samples from coniferous forests at 87–103 sites were used to elucidate how natural processes and human activities throughout a 500 km 2 area in western Finland have affected the content, accumulation and dispersion of P, K, Ca, Mg, Fe, S, B, Cu, Zn, Mn, Cd, Cr, Ni and Pb in the environment. Abundance, correlations and spatial trends between and within the organic, biological and inorganic compartments were determined. No evident spatial trends existed for K, P, S, Mn, Mg and Ca. The distribution of these macronutrients in and between the media is controlled, to a high degree, by biological cycling; thus the nutrient levels are optimized in the various media. Low correlation coefficients for Ca, P, K, S and Mg between humus and moss, and the low spread of these nutrients in moss and needles, are other strong indications of efficient recycling. No correlation existed between the concentrations of B and the distance from the coast, suggesting that the B patterns are unaffected by deposition of marine salts. There was a strong spatial pattern for B in humus, moss and needles, probably connected with anthropogenic emissions from a nearby town centre. Geogenic dust affected the spatial distribution and the high correlation between Fe and Cr in moss, while natural processes were associated with the Fe anomaly found in the needles. The spatial accumulation patterns of Zn, Cd, Cu, Ni and Pb in humus and moss were strong and diverse and related to current industry, the former steel industry, traffic, coal combustion, and natural geochemical processes. An intriguing Cu anomaly in moss, probably caused by corrosion of the railway line's electric cables, was identified.

Environmental odor annoyance from air pollution from steel industry and bio-fuel processing

Calibration with the master-scale procedure provides a defined unit of measurement for direct comparison between subjective reports from different individuals, obtained at different occasions, and in different contextual settings. A standard set of reference stimuli and the environmental target stimulus are rated on the same scale. The applicability of this procedure was demonstrated by applying it to odor annoyance from environmental pollution at three sites in communities with steel industry (Study 1) and bio-fuel processing (Study 2). Series of pyridine concentrations were used as reference stimuli that, together with the environmental target stimuli, were judged with magnitude estimation by participants with normal olfactory function. The results provide annoyance estimates for each of the six sites expressed in master-scale units and in pyridine equivalents that are directly comparable with each other and with those from other environmental studies using this procedure.

Physical modeling simulations of refining processes in Brazilian Steel Industry

In this work, the techniques of physical modeling for optimization, control and improvement of metallurgical processes, such as RH degassing, continuous casting, IR‐UT, etc with special reference to Brazilian steel plants such as Usiminas, CST, Belgo‐Mineira etc. are discussed. Many of these have been industry‐sponsored projects, involving development of physical models of laboratory scale, considering similarity principles and carrying over the results of experiments to the industrial unit, for optimizing the processes or suggesting alternative techniques for improved efficiency.

Work systems, corporate strategy and global markets: creative shop floors or ‘a barge mentality’?

ABSTRACTIn the US, corporate restructuring of financial and physical assets as well as work systems has been widespread. Our study examines the inter‐relationship between ‘creative’ work systems and ‘destructive’ markets, using a sample of US manufacturing firms in the metalworking, jet engine production and steel processing industries.

Consideration and Practice of Science, Technology and Strategy for Minimizing CO2 Emission in Chinese Steel Industry

In order to minimize CO 2 emission from iron and steel-making processes to abate greenhouse gas impact, the considerations and some practice of science and technology as well as its strategy completed and on going in Chinese steel industry are summarized. Two available ways for the minimizing in China so far: (1) Minimizing carbon-consumption (fossil energy-saving) in all the processes of steel industry which is the most realizable measure for reducing CO 2 emission. (2) To look for new alternative reaction medium in the processes where producing more CO 2 like H 2 in blast furnace etc and new processes for iron and steel making which discharge less CO 2 . Some new ideas like macro-based measures are put forward for minimizing CO 2 emission in steel industry.

Creative work systems in destructive markets

In the United States, the past twenty years have been marked by significant restructuring of both financial and physical corporate assets designed to strengthen firms' relative market position either voluntarily or in response to the threat of take-over. Firms have also restructured work systems in an effort to improve production efficiency, product quality and flexibility. While most studies find that these new workplace techniques generate substantive productivity and quality gains and financial results that are equal if not superior to those associated with more traditional work systems, in the U.S., they have proven difficult to maintain. Diffusion is slow and not extensive; and even the most promising cases have either failed or come under extreme pressure, both internal and external. Using the productive systems approach, our study examines the inter-relationship between creative work systems and destructive markets using a sample of U.S. manufacturing firms in the metalworking, jet engine production and steel processing industries.

Creative Work Systems in Destructive Markets

In the United States, the past twenty years have been marked by significant restructuring of both financial and physical corporate assets designed to strengthen firms' relative market position either voluntarily or in response to the threat of take-over. Firms have also restructured work systems in an effort to improve production efficiency, product quality and flexibility. While most studies find that these new workplace techniques generate substantive productivity and quality gains and financial results that are equal if not superior to those associated with more traditional work systems, in the U.S., they have proven difficult to maintain. Diffusion is slow and not extensive; and even the most promising cases have either failed or come under extreme pressure, both internal and external. Using the productive systems approach, our study examines the inter-relationship between creative work systems and destructive markets using a sample of U.S. manufacturing firms in the metalworking, jet engine production and steel processing industries.