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By Amilton Feliciano Castro

In this work, activated carbons (ACs) were prepared using Sewage sludge as starting material. The ACs were pyrolyzed in an inert atmosphere at 550 °C after independent chemical treatment with ZnCl2 or KOH with ratio of 1:1. The materials were used as adsorbents for removal of Cu(II) from aqueous solutions. The adsorbents were characterized using adsorption/desorption nitrogen isotherm, SEM (scanning electron microscopy). The results showed that copper removal could be linked to surface pH and compounds present on the surface of adsorbent. KOH-treated adsorbent has smaller surface area (186 m2 g-1) than ZnCl2-treated adsorbent (192 m2 g-1), however, KOH-treated adsorbent exhibited higher removal of Cu(II). The performance of KOH-treated adsorbent could be attributed to the presence of basic groups on the adsorbent surface. Liu isotherm model gave the best description of the equilibrium data. From the Liu isotherm, the maximum adsorption capacities at 298 K for KOH-treated, ZnCl2-treated and sewage sludge (without inorganic activation) adsorbents are 31.85, 19.79 and 3.513 mg g-1, respectively. The best desorption experiment was obtained using 1.50 mol L-1 of HNO3 as eluent. Recoveries of Cu(II) from Cu(II)-loaded adsorbents are 98.9% (ZnCl2-treated) and 95.5% (KOH-treated.

Aug 17, 2017

By Thomas Schanz

Current steel market conditions require small investments only to lower operational cost. SMS Concast has developed new products which optimize continuous casting process cost for long product steel production. This paper describes a selection of three products. All three systems are patented (patent pending for CONDRIVE). CONSAFE, a non-radioactive mould level measurement system for reliable mould level measuring on open stream casting CCM’s; CONSTIR-MWS, an improved control software for electromagnetic stirrers which lowers energy cost by 35%; CONDRIVE, a brand new oscillation drive system which provides the features of a hydraulic oscillator, however with a cost efficient electric drive.

Aug 17, 2017

By Ernst Lindemann

The SMS group has developed the ultrasound technology “HD scan” for inspection of the internal quality of as-cast products. This method of sample analysis requires less preparation work and is safer than the current, most common technique of etching and/or sulphur printing. Furthermore, this technology offers a three-dimensional view into the sample of the cast product and thus more representative information for a better quality evaluation. The internal quality evaluation can be performed automatically and objectively by software based on clear statistical methods. A quantitative centerline segregation rating can be assigned to each sample, based on the size and distribution of segregates detected by the unit. Internal crack statistic (length, position, orientation, etc.) and narrow side profile can also be measured. Grain macrostructure can also be visualized which allows for a potential optimization of casting parameters like strand cooling, soft reduction or electromagnetic stirring. The accuracy of the new method was proven by parallel metallographic investigations of more than 100 samples of different steel grades and sample shapes. Automatic defect evaluation and classification was compared against macroetching results. It was found that HD scan identified more defects and the visualization of the macro structure could be performed in more cases than with macro etching. All tests, comparisons, further developments and analyses for various steel producers and steel treatment companies have been conducted at the HD scan unit, located at the SMS group headquarters in Düsseldorf, Germany (Figure 1). Based on the results, SMS group has designed a unit which can be used in industrial scale.

Aug 17, 2017

By Karl Berger

As the hot rolling of steel moves into new more compact and effective processes, and as steel producers look for new ways to reduce their costs and increase their margins in ever tightening markets and tolerances, the evolution in Steckel mill technology, layouts, and new innovations may well keep the Steckel mill as a viable option, especially in areas of the world where minimized capital investments are required. In this paper we examine the evolution of the Steckel mills over the last two decades, with emphasis on new innovations and practical results, and provide a summary of hands on experience with some of these innovations. Also a focus on the South American Installations is given (from Siderperu to Gerdau’s newest Combination- Plate-Steckel-Mill). In addition, we aim to show the viability of the Steckel mill as an option for many existing or prospective steel producers, as the quality of the products rolled with Steckel mills reaches new quality parameters and as new innovations permit the rolling of thinner and wider materials, reaching new applications and wider share in markets, while maintaining a strong foothold in the traditional uses of Steckel mill products such as stainless steel, structural, and line pipe materials. As the ability to handle heavier, thicker, and wider coiled plate products increases, the coiled plate Steckel mills option is as strong an option as ever.

Aug 17, 2017

By Konrad Krimpelstätter

The need for more effective and flexible roll-gap lubrication technologies in hot and cold rolling mills is steadily increasing due to ever-greater requirements placed on the rolling process and the final products. In particular, the rolling of high-strength steels poses enormous demands for both the rolling mill and the coolant/lubricant to be used. The presented paper focuses on two innovative technologies for highly efficient roll-gap lubrication for hot and cold rolling, which were developed utilizing extensive knowledge and expertise about the tribological interactions in the roll-gap. The advanced work-roll lubrication package (A-WRL) for hot rolling and ESP mills is using specially designed mixer-nozzle units to mix the water/oil emulsion very close to the nozzles to minimize the risk for contamination and clogging. The nozzles are quickly exchangeable and are optimized to ensure uniform lubricant distribution, high plateout efficiency and minimum oil consumption. This eco-friendly solution does not require any chemical additives or cleaning agents and significantly reduces electrical energy consumption and work-roll wear. The roll cooling system on mill entry and exit side remains switched-on, which is of vital importance especially for highperformance hot strip mills. Minimum Quantity Lubrication MQL® represents a new generation of roll-gap lubrication technologies for cold rolling, which applies minimum amounts of pure rolling oil finely atomized with pressurized air directly onto the work roll surface. This allows controlling the oil film thickness depending on actual process and product parameters, providing increased lubrication flexibility, significant improvement of strip surface cleanliness through reduction of strip wear. MQL® was successfully installed and tested on two industrial tandem cold rolling mills in Europe. Advanced WRL and MQL® represent Primetals’ latest technologies that feature a robust and reliable system comprising standardized interfaces and flexible communication options. Both packages can easily be integrated into existing or new hot strip mills, ESP lines or cold mills.

Aug 17, 2017

By Ronaldo Câmara Cozza

Iron aluminide alloy; Ball-cratering wear testing; Rolling abrasion; Wear volume; Coefficient of friction

Jul 31, 2018

By Günther Staudinge

Aperam is a global player in producing of stainless, electrical and special steel qualities. The steelmaking plant in Timoteo Brasil is equipped with one AODconverter for stainless steel and one MRPL-converter for special steel production. After almost 20 years of operation Aperam decided to exchange the existing 80 t MRP-L converter by a new one including a new trunnion ring and a state of the art suspension system. Due to an optimized design the inner volume of the new converter could be increased which comes along with improved production. A special feature is a flange connection in the barrel section of the converter. This allowed to avoid any critical site welding and the time between shut down of the old and cold commissioning of the new converter could be done with 17 days only.

Aug 17, 2017

By Qingwen Dai

The Marangoni effect is an important phenomenon where a surface tension gradient drives liquid towards high surface tension regions. Temperature gradient, evaporation, disparity of viscosity, and surface roughness and topography are all significant factors that can affect this thermo-capillary migration. The purpose of this study was to investigate the influence of micro-groove patterns on the migration of paraffin oil, and obtain a well-designed texture of micro-grooves to prevent the thermo-capillary migration. Patterns of micro-grooves with differing orientations and geometric parameters were fabricated on the surface of SUS 316 stainless steel substrates. Experiments on the migration behavior with different viscosities of paraffin oils were carried out various temperature gradients. The experimental phenomena indicated that the surface with the micro-grooves perpendicular or parallel to the temperature gradient have a strong impact on the migration performance of paraffin oil. Micro-grooves perpendicular to the temperature gradient exhibited extraordinary slower migration velocity than that of the parallel one. Width and depth of micro-grooves had an obvious influence on the behavior of temperature-driven migration and detail discussions on the effects of these geometric parameters were carried out.

Jul 31, 2018

By Maurizio Massimo

Danieli developed the “3Q” suite of process control technologies to address three critical principles: delivering the highest product Quality, in the required Quantity, with Quickness of response required for today’s casting machines. Ever increasing market demands for productivity and slab quality necessitate the latest advances/improvements in equipment design, process technology, and control software for all types of slab casters, and Danieli boasts a unique experience that extends from ultra high-speed thin slab casters to extra high-thickness conventional slab casters. The “3Q” system is monitored and controlled by a unique, intelligent HMI incorporating. Touch screen technology and Operator Assistant tablets. Operator Assistant is a tablet based system that guides the operator through the plant process, so that in the event of a process change or an alarm the operator is automatically presented with the choice of possible solutions / actions. The comprehensive range of technological packages cover all aspects of caster design and automation control, from feeding of liquid steel into the tundish to the final slab leaving the caster.

Aug 17, 2017

By Daniel Eduardo Parodi

Para acompañar el plan de aumento de producción de slabs de Siderar, fue necesario proyectar una nueva unidad separadora de aire para incrementar la generación de oxígeno, nitrógeno y argón. La premisa que direccionó este proyecto fue la integración y sinergia de la nueva unidad con el sistema de la Central Termoeléctrica y Altos Hornos, con el objetivo de salvar condicionamientos, obtener beneficios energéticos y aumentar la confiabilidad operativa. Como resultados de esta línea de trabajo se espera: Optimizar el aprovechamiento de gases de proceso, mejorando así el balance energético y la ecuación económica en la producción de los gases industriales; Mejorar el aspecto ambiental disminuyendo el quemado de gases en antorcha, reduciendo el consumo de combustibles fósiles y la compra de energía eléctrica; y aumentar la confiabilidad en el suministro de gases y del sistema de aire soplado a Altos Hornos.

Sep 25, 2017

By Companhia Siderúrgica Nacional - CSN

Balanço Energético Global 2013

Jul 31, 2018

By Alessandra Spaghetti

Rolling small-diameter hot wire rods at high speeds with conventional laying head pipes can wear the pipe out frequently and affect quality and consistency in the final product. Laying head upgrades using Sandvik SAF2507LHP™ (UNS S32750) tubes make possible to achieve optimal metallurgical properties, smooth coil formation and easier coil handling. Operators can also avoid unwelcome shutdowns due to frequent worn pipe changes and turndowns. Sandvik have been developing different customers and understand their process needs. The suitable selection materials that are able to withstand high levels of wear better than low alloy and carbon steel grades that are commonly used in industry is very important to improve the quality and increase productivity. UNS S32750 tubes were demonstrably superior to low alloy and carbon steels when used in Laying Head Pipe system regarding tubes lifetime, reducing replacement, production interruptions and increasing reliability.

Aug 17, 2017

By Werner Klein

The utilization of production facilities in an optimum way, with reliable due date fulfillment, reducing raw material and energy consumption, are challenges iron and steel companies are facing in their business every day. By using an APS system such goals can be achieved to increase the competiveness of iron and steel producers. A sophisticated APS supports the overall planning process by applying complex rules based on product and order mix, its production routings with corresponding processing and transport times and resource availability. Specific technological as well as steel grade and energy related constraints are also considered to meet company specific KPIs. A core feature of APS solution is to react online on deviations to plan during the production process. Deviations such as nonconformance of intermediate material attached to an order, sudden production delays, unavailability of important production resources, makes it necessary to update the production plan. In general the task of APS is to support the preferred work-to-order concept, by assigning work-orders to available production facilities along the product specific process route and generate optimized material sequences for critical work centers.

Aug 17, 2017

By Jörg Thomasberger

Delivering liquid steel to a steel processing unit at right temperature is an important criterion for high production steel shops, but it is surprising how little attention has been paid in the past to manage this vital phase in the steelmaking process-the steel in transit. The ladle running costs, both directly and indirectly, contribute significantly to the cost of steelmaking and should be an area of concern to any high production steel plant. Here we are talking not only of refractory costs or preheating fuel costs, but also cost of extra heating in ladle furnace, additional process delays incurred in delivering steel at right temperature to downstream unit in case proper care is not exercised at upstream unit, and occasional costs of ladle breakout due to inability to judge the residual life of the ladle. This paper emphasizes the need of a comprehensive ladle management system, an aspect which has not been properly addressed in the operations of a steel plant, in improving the productivity of a steel melt shop. Starting with review of present status and the attempts at implementation of ladle tracking in steel melt shop automation system, it looks at components of an exhaustive Ladle Management System (LMS), and finally gives an idea of benefits that will accrue from implementation of such a system in a steel melt shop.

Aug 17, 2017

By Claude Bodeving

The present steel economy drastically increases the financial strain on blast furnace operators. As a consequence, the importance of reliable cast floor operations is increasing drastically, which has a direct influence on the required clay mass and tapping equipment performances. When using modern high performance clay masses, pneumatic taphole drilling machines quickly reach their performance limits, which has made fully hydraulic drill hammers a standard in modern cast house operation. Besides the well-established hydraulic TMT hammers with high impact energy, an alternative version with lower impact energy, but high impact frequency was developed by TMT in the past, in order to achieve improved taphole protection. TMT’s recent research has shown that the drilling requirements inflicted by the taphole condition change over the taphole length, which has triggered the development of a new hammer, capable of switching between a high impact frequency mode and a high impact energy mode.

Aug 17, 2017

By Fernando Henrique Gomes de Souza

Techniques which use a spring to supply the bias force to actuator are well adopted since they are inexpensive and simple to construct. In this work it was design an actuator concept using bias-type device technique, which comprises two coils that mutually push against each other to supply the stroke. For the coils springs, it was used a wire of NiTi shape memory alloys (SMA) and a wire of 400 grade maraging steel as construction materials.

Aug 8, 2018

By José Aparecido Pereira

The innovative methodology developed by the author allows the elaboration of an Angle Roll Pass Design based on the practical observations of the rolling process and applies mathematical criteria, using the Ekelund´s formula supported by Advanced Excel tools (Reach Goal, PROCV-PROCH, Macros) and AutoCad. The first step is the definition of the number of stands, roll dimensions, gear boxes reduction, initial stock, average reductions, spread factors, finishing speed and type of grooves. For each pass are calculated: bite angle, spread, section reduction, lost and gain of temperature, separating force, speed, torque and motor power. After these calculations and checking of the parameters, the program calculates the dimensions of the passes transforming the flat passes into shaped ones. With these dimensions it is possible to draw the grooves using AutoCad and check section reductions. This methodology was already used for the development of a new project and also to check the parameters of existing ones, with comparison of the results and has shown to be reliable in real and tested projects. It is an innovative process that is not available in known literature.

Oct 1, 2019

By Masahiro Shimura, Yoshiki Takahama, Toshiyuki Shiraishi, Daisuke Kasai

When advanced high strength steel (AHSS) is rolled at a high reduction ratio, the forward slip ratio in cold rolling tends to be lower than that of the other softer strips such as low-carbon steels, and the work roll sometimes skids the strip. To identify why forward slip ratio of AHSS at a high reduction ratio becomes smaller than that of low-carbon steel, the relationship between the reduction ratio and forward slip ratio was investigated by a rolling experiment. For this trial, a 4Hi laboratory cold mill was used. AHSS and low-carbon steel coils were rolled by two different rolls that were set to 0.3 and 0.6 μmRa to create two types of friction conditions. Furthermore, the rolling conditions were numerically analyzed to determine the influence of friction coefficient and flow stress on the relationship between forward slip ratio and reduction ratio. The experimental investigation and numerical analysis revealed that the forward slip ratio reduced with increasing rolling reduction ratio in a low friction state; contrarily, it increased with increasing rolling reduction ratio in a high friction state. This feature was clearly visible when harder materials were rolled.

Oct 1, 2019

By Daniel Antonio Kapper Fabricio

A avaliação das propriedades de mecânica da fratura dos materiais é uma necessidade crescente, sobretudo no setor de óleo e gás. Esse cenário exige a garantia da qualidade na execução de ensaios de tenacidade à fratura. Esse trabalho tem como objetivo realizar uma comparação intralaboratorial para o ensaio de tenacidade à fratura KIC variando o executante do ensaio, visando atender ao requisito de garantia da qualidade da norma NBR ISO/IEC 17025. Os resultados foram comparados através de análise de variância. As diferenças entre os operadores não foram significativas frente ao erro residual a um nível de confiança de 95%, sendo tal resultado considerado satisfatório.

Aug 16, 2017

By Márcio Corrêa de Carvalho

Welded deposited chromium carbide overlay’s has been widely used in various branches of welding overlay’s industry related to wear. Characterization techniques are an important tool in the development of chromium carbide overlays resistant to wear, enabling the identification of phases, constituents and defects. In this work one used optical microscopy, scanning electron microscopy and energy dispersive spectroscopy on chromium carbide overlay’s deposited by submerged arc welding process. The characterization techniques identified precisely the elements of the overlay’s enabling point of the main cause of the observed defects such as cracks, porosity and clusters of particles known in the industry as " rice crispy" .

Aug 16, 2017