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By Juergen Meisel

The paper will explain how to successfully implement a robotic solution from the initial idea to a working industrial solution. Primetals Technologies can call upon 10 years of experience in installation of Robot solutions in the harsh environment of steelmaking plants - the so-called LiquiRob. To enhance an existing shroud manipulation system, the idea to connect the shroud with a bayonet mechanism to the ladle nozzle was born in accordance with the requirements of a well-known steel producer. The paper will describe the development steps from the first simulations and prototype testing in the laboratory, it will show the intensive system testing under workshop conditions and will finally depict the successful integration into the plant. Furthermore, operational experience will be shown as well as the advantages of such an installation compared to other shroud manipulation systems.

Oct 30, 2017

By Eleir Mundim Bortoleto

A finite element modeling approach was developed to study adhesion phenomena during the unidirectional contact between a two-dimensional plane-strain square and a flat slab. Surfaces were metallic or ceramic, different pairs of materials were analyzed and their adhesion was considered by means of a FORTRAN subroutine (DLOAD), which was connected with commercial finite element code Abaqus and provided surface attractive forces based on the Lennard-Jones interatomic potential. Adhesive loads were considered both during approximation and separation of the surfaces. During the separation step, material transfer between surfaces, due to adhesion, was modeled by means of damage initiation and propagation at the flat slab. The parameters considered in the simulations were normal load, chemical affinity and system size and the different conditions were analyzed by comparison of the interaction forces during approach and withdrawal. This work also presents detailed descriptions of: (i) the evolution of energy dissipation due to adhesion hysteresis, (ii) the formation-growth-breakage of adhesive junctions and (iii) the evolution of stress distribution during the process. Results have indicated that chemical affinity between the bodies in contact is more relevant for adhesion than the applied load. Besides, smaller asperities are less prone to promote adhesive wear, but they may be subjected to high stress concentration effects.

Jul 31, 2018

By Raúl Daniel López

Ternium-Siderar steelmaking has been focused in permanent improvements and process optimization. At present the Slab Continuous Caster N°1 has been totally transformed after 20 years of uninterrupted work. The authors of this paper summarize and comment on aspects which were the main changes and place emphasis largely on those technological developments in which they have been active during that period. Productivity and quality have been our goals during the last 20 years; it has led us to improve process and to achieve better control tools. In the development of this presentation, the authors will put special emphasis on the explanation of those works that were made following their own experiences through the technical personnel who belong to the staff of the company.

Jul 30, 2018

By Alessandro Martinis

The performance requirements for modern steelmaking facilities are ever more stringent, as customers and markets are continuously pushing for technologies which allow having high quality steel produced in an economic and sustainable way. In the details, this paper has the aim to present the excellent results obtained by integrated steel plant where an EAF is fed with high quality hot ENERGIRON DRI. The recent technology developments, combined with the affirmed basic process design, contributed to further maximize the energy of the DRI, reaching the EAF at temperatures above 600°C with a carbon content up to 3.5%, as confirmed by plant data. These improved input material characteristics resulted in reduced electrical energy consumption and increased liquid steel production.

Aug 16, 2017

By Daniel Augusto Godinho de Carvalho

Since the beginning of BOF process, slag formation has been subjected to extensive development. During the initial stages of the blow, fast slag formation is primordial for the process performance. This is mainly to allow oxidizing reactions, and also to protect the refractory. A modeling of BOF process for the purpose of process optimization requires precise knowledge concerning the dissolution of CaO and MgO based materials. Using this knowledge, the optimal process conditions can be ensured by a controlling of the slag formation during the converter steelmaking process. Taking into account an application of large amount of different raw materials, as well as location-specific process conditions, the characterization of the dissolution behavior of different additives is an important key to improve the technological process. Thereby, in the frames of this project, an appropriate model for slag formation is established and compared to operational results for a 330t BOF, operating at ThyssenKrupp CSA, Santa Cruz, Brazil.

Aug 16, 2017

By Anand Kumar Agrawal, Kinzel Klaus Peter, Lorenzo Micheletti, Cristiano Castagnola, Horst Kappes, Andre Oliveira, Björn Rösner, Philippe Bermes

Blast furnaces are widely employed today for iron production all around the world, with a total production of around 1.2 billion tons per year. Its operating principle, which relies on usage of coke to reduce the ore, to ensure the permeability in the reaction vessel, to maintain its flexibility of operation and acceptability for varying qualities of iron ores. The blast furnace route is widely considered as the most economic and efficient route of iron production, however it is based on fossil energy carriers. The blast furnace route has undergone significant developments in terms of energy efficiency in the last decades, which led to a substantial reduction in the use of fossil reduction materials. Being an energy intensive process, competitiveness and cost saving in the blast furnace plant was always strongly related to the saving of energy and hence reduction of CO2 emissions. In addition to this, EU emissions trading system (EU ETS) as a cornerstone of the EU's policy in response to climate change has set new “challenges” for iron production in Europe. Paul Wurth has always been deeply involved in the development of energy saving technologies for blast furnaces. In the following a review of energy saving achievements developed in the last decades will be presented and the potential of available CO2 saving technologies will be summarized. Additionally, an outlook about the potential of future technologies, concepts and their impact on the blast furnace and the steel plant’s energy balance will be discussed. Finally, the replacement of carbon by hydrogen as reduction agent in the steel plant will be reviewed, with special focus on a comparison of costs and incentives.

Oct 1, 2019

By Charles Sóstenes Assunção

A mathematical model of heat transfer and solidification for a continuous casting of round billets was developed. The water flux density of the secondary cooling zone was experimentally measured, using an apparatus in industrial scale with two types of nozzles, flat jet and full cone jet. The profiles of water distribution were applied on the mathematical model. The results showed that the water distribution is not uniform in both longitudinal and angular directions owing to the unevenness of the spray and to the curvature effect of the round billet. This non-uniformity causes important variation of the heat transfer coefficients and superficial temperature of the billet, especially in the first cooling zones, where the temperature is higher. The mathematical model was used to simulate a change of nozzle type in the first cooling zone. The results showed that the heat flux and superficial temperature variations were reduced with a full cone jet nozzle in comparison with the flat jet nozzles.

Aug 16, 2017

By Mühlböck Marlene

Increasingly stringent global environmental regulations are forcing steel producers to continually improve the efficiency of sinter waste gas treatment. With the Selective Waste Gas Recirculation (SWGR) system from Primetals Technologies, lower production costs can be achieved and the size of downstream waste gas cleaning units can be reduced for investment savings. SWGR features the extraction and reuse of hot sinter off gas from selected wind boxes along the sinter strand, which contributes to improved energy efficiency and off gas treatment in the sintering process. With the next generation of SWGR, Primetals Technologies can provide an energy optimized, emission optimized and environmentally friendly solution that meet customer requirements and country specific regulations. This paper demonstrates the latest developments in selective waste gas recirculation, especially results from pot grate tests and comparison from lab to real plant data. Furthermore theoretical finding and mathematical modelling is presented.

Aug 16, 2017

By Humberto Tronconi Coelho

The use of friction dampers are wide proposed for a variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers. An important example is the application of friction dampers in aircraft engines to reduce the blades vibration amplitudes. In most cases, friction dampers have been studied in a passive way, however, a significant improvement can be achieved by controlling the normal force in the contact region. The aim of this paper is to study four control strategies for friction dampers based on three different hysteresis cycles. The first control strategy maximizes the energy removal in each harmonic oscillation cycle, by calculating the optimum normal force based on the last displacement peak. The second control strategy combines the first one with the maximum energy removal strategy used in the smart spring devices. Finally, is presented the strategy which homogenously modulates the friction force. Numerical studies were performed with these four strategies defining the performance metrics. The best control strategy was applied experimentally. The experimental test rig was fully identified and its parameters were used for numerical simulations. The obtained results have shown the good performance for the friction damper and selected strategy, also, the agreement between numerical and experimental results.

Jul 31, 2018

By Jean François Stumper

This paper presents the TMT “3D TopScan” profilemeter, which is a Radar-based profilemeter that measures the total burden surface within a few seconds and on a continuous basis. This equipment is based on an electronically steered solid-state radar scanner, such that a very large amount of surface data is collected within short time intervals. These new electronically steered antenna systems are the key to meet the demands for both accuracy and speed. The TMT probe is installed at a fixed location at the top cone, such that it does not interfere with the charging, enabling a continuous measurement and a compact design.Blast furnace charging optimization can be achieved based on its measurement data. The burden surface is continuously measured every few seconds, enabling the blast furnace operator to detect any details including asymmetries or irregularities in the surface pattern. A variety of process analysis tools are available. Due to the continuous and fast measurement, the burden descent speed can be supervised without process interruption on an ongoing basis. More accurate process models (layer models) than ever are obtained which fully consider the unsymmetries.This technology, developed by TMT Tapping Measuring Technology, is successfully in operation at Salzgitter Flachstahl GmbH at their blast furnace B. The probe and the data evaluation tools combine today’s technological capabilities in measurement technology with the practical requirements of blast furnace operation.

Aug 16, 2017

By Mingyu Ma, Lingling Liu, Liqing Chen, Houlong Liu

In this article, a 444-type heat-resistant ferritic stainless steel containing 0.05wt% Ce and 2wt% (Mo+W) was used as an experimental material and a study was carried out on the effect of rolling processes on the microstructures and texture evolution as well as on the mechanical properties and formability. The rolling processes contain hot rolling at different hot rolling finish temperatures, annealing after hot rolling, cold rolling and subsequent annealing. As for the hot rolling process, two hot rolling finish temperatures, 860 C and 770 C, were adopted, and their influence on the microstructures and mechanical properties was comparatively studied. The results showed that the microstructures after hot rolling and subsequent annealing could be refined by lowering the hot rolling finish temperature. The resultant microstructures after cold rolling and annealing were hereditarily refined. Lowering the hot rolling finish temperature can weaken the -fiber texture in hot rolled or cold rolled ferritic stainless steel strip. However, the -fiber texture was homogeneously strengthened by annealing the cold rolled ferritic stainless steel strip. Enhanced mechanical property and formability in terms of strength and average plastic strain ratio could be obtained by lowering the hot rolling finish temperature of ferritic stainless steel.

Oct 1, 2019

By Ananda Moreira Vaz Ourique de Avila

Ferritic stainless steels have been used in the making of high and intermediate temperature operation solid oxide fuel cells (SOFC) interconnects, replacing the ceramic materials. However, at high temperatures, on the order of 700-850 0C, these steels can present significant oxidation and degradation processes, promoting increased electrical resistivity and corrosion losses that result in contamination of the electrodes and reducing the performance and the useful life of the SOFC. Thus, the knowledge on kinetics of oxidation/corrosion of these steels and their relationship with the microstructural transformations are of great importance. In this study, samples of ferritic stainless steels AISI 430, AISI 441 and Crofer22APU® were tested for oxidation at high temperature (800 0C) for long periods of time (up to 3,600 hours) and mass gains were monitored allowing the determination of the oxidation behaviors of these steels. Additionally, the microstructural characteristics of the samples before aging (corrosion-oxidation test) and after various oxidation times were evaluated by optical (OM) and scanning electron microscopy (SEM), as well as by micro chemical elemental analysis (EDS) and X-ray diffraction (XRD) phase analysis. Electrical characterization allowed determination of electrical area-specific resistances (ASR) characteristics of the systems studied, thus relating the electrical and oxidative behaviors of steels evaluated.

Aug 7, 2018

By Daniel Carvalho, Marcos Viana, Leonardo Demuner, Herbert Castro

Intensive process and technology improvements related to the BOF converter — the key process to increase steel plant productivity and stability — have been performed at Ternium Brazil. This paper details the road map for process developments and investments in equipment technology, as well as the results achieved. The main topics of this development are the process control and optimization systems, slag forming model, oxygen blowing pattern, end-of-blow point control and slag carryover control. The outcomes of this development are improvements in the reblow rate, end-of-blow oxidation, direct tapping, slag carryover, slopping ratio, metallic yield and lining life.

Oct 1, 2019

By Jan Krull

A high productive coke making process in connection with stringent emission control has clearly become a demand of plant operators and stakeholders. Further to this, availability, quality and coal costs are key concerns for the iron and steel industry in its efforts to optimize raw material cost. Today, the optimization of raw material cost in integrated steel works has further gained priority. Coking coal reflects up to 20% of the cost of steel. In top charged batteries coal preparation and blending is one of the concerns to lower coal cost by maximizing the percentage of non-coking coals in the blend. Stamp charging technology is technologically and economically an effective solution in the process of pre-carbonisation. Paul Wurth’s jumbo top charged oven as well as proven stamp charging technology have recently set new benchmarks in Europe, India and Brazil in terms of productivity, stability and emission control.

Aug 1, 2018

By Washington Martins da Silva Júnior

In stamping process, sliding between metal sheet and forming tool leads to wear of tool surface. Maintenance of stamping tools involves polishing the tool edge, or, in case of severe damage, replacement of the tool. Hard coatings have been applied on the stamping tool surfaces in order to reduce the maintenance cost causing a great economic impact in metal work industry. In this work, CrAlSiN coatings were applied by PVD onto SRV2W tool steel. The coating toughness was avaliated by the critical load in scratch tests. The following coating parameters were analyzed: 1- substrate surface finishing process; 2- coating architecture (multilayer or gradient); 3- chemical composition of the coating. AlSi concentration varied from the substrate/coating interface to the surface. Coatings were 3 µm thick. Scratch tests were carried out using a Vickers indenter. The applied normal load was varied from 0 to 13 N for a scratch length of 5 mm. In order to study the effect in the toughness, the substrate roughness was controlled by the finishing process before PVD coating. Samples subjected to polishing presented highest critical loads. Gradient coatings presented higher critical loads than those with a multilayer architecture. Coatings with higher concentration of AlSi near the surface supported higher loads before failure.

Jul 31, 2018

By Francisco Morganti

In order to support hot rolling mill managers in improving the utilization of their plants, SMS group offers well defined Performance Modules. These are technologies, components, automation solutions or services, which can be implemented in existing plants to increase competitiveness in categories of efficiency, productivity, quality and process and product control referred to as “Industry 4.0”. Except the Performance Modules dedicated to the last category, targeting overall process controls, Performance Modules are characterized by quantifiable benefits. Performance Modules related to hot rolling mills are e.g. camber free rolling, modular laminar strip cooling system, new edge masking and intelligent components.

Oct 30, 2017

By Felipe Beluche Lima, Caio Augusto Silva Santos

Brazil is the largest producer of crude steel in the Americas by BOF process and many challenges come along with the increasing market demand. In the BOF, a tubular wall hood structure has been showing premature failures related to the overlay welded tube technology placed in the hood wall. The main root causes were: thermal fatigue at 1800°C, hot spot formation, high heat-affected zone (HAZ) leading to susceptibility of stress cracking, carburizing corrosion and superficial wearing. Based on that, co-extruded tube technology (named composite tube by Sandvik) was the alternative chosen to enhance hood performance without compromising BOF process. In order to rises safety and productivity, composite tube has 100% metallurgical bond assuring stable expansion, high heat exchange efficiency, better corrosion resistance and less rough surface finishing. It was highly suggested to many others mills due to similar and already existing reported cases.

Oct 1, 2019

By Luigi Giacomini, Bruce Kiefer

A new plant for special steel long products was commissioned in recent years at Dangjin, South Korea, for Hyundai Steel. Two multi-line rolling mills can produce yearly 1 million tons of billets, straight and coiled bars, with dimensions from 5.5 to 350 millimeters. The products are used for manufacturing engine and transmission components used by Hyundai Kia Automotive Group. The processed grades include carbon, special alloy, spring, bearing and free-cutting steel. The first mill rolls blooms into finished large round and square products, as well as into intermediate billets. A 2-high reversing breakdown stand is followed by a finishing and sizing train with CGA stands equipped with an under-load roll parting system for automatic gap control. The second mill combines lines of small bars, rods and bars-in-coil. Billets are rolled in a continuous rolling mill with original RedRing Series 5 stands. The rod outlet features Morgan No-Twist and Rod Reducing/Sizing mills, Morgan High-Speed Laying Head and Stelmor conveyor. Advanced sensors and electronics integrate with mechatronic packages, thus equipping the mill for Industry 4.0 applications. Hyundai can meet the demanding requirements posed by the automotive industry and benefit from optimized conversion costs, the flexibility to meet market changes, achieve high product quality, and reduce floor personnel.

Oct 1, 2019

By D. F. Rodríguez-Pérez, J. Salinas-Reyes, Luis R. Salazar-Garza, C. A. Gómez-De-La-Garza

The Pickling Line Tandem Cold Mill (PLTCM) from Ternium Pesquería started in 2013. It is a line with 5 stands, 6 high; focused mainly on the exposed automotive market, with a wide spread of products with high quality requirements. In addition the operational continuity is very important, for this, one of the greatest challenges is to ensure operational discipline, the order of production, the quality of the input (hot band), operational interruptions, equipment failure, breakage of strip in the mill, among others. In relation to this, it has a strong impact on productivity, customer compliance, damage to equipment, rolls, safety, quality, reprocessing among others. Here is present the results obtained in the project "decrease of strip breaks" which focused on several fronts, discipline in the order of production, previous review of raw material in surface and dimensional defects with automatic inspection equipment in the hot mill, as well as in PLTCM, generation of logic in the redundant systems of alerts and prevention to avoid or minimize strip breaks that were high impact in the past. All these multidisciplinary actions led as a whole to a significant improvement in the performance indicators of the PLTCM, in productivity, compliance, reprocessing and quality in the cold rolled mill.

Oct 1, 2019

By Samuel Filgueiras Rodrigues

An austenitic stainless steel ISO 5832-9 was deformed in a torsion test machine over the temperature range of 1,000°C – 1,200°C and strain rates of 0.05, 0.1, 1.0 and 5.0s-1. The Steel plastic behavior was studied by analyzing the flow curves shapes and using the constitutive equations under the conditions of thermomechanical treatment. The curves initially presented an increase in stress characterized by hardening work, followed by a drop in stress to an intermediate level that reached or not, for certain conditions, the steady state softening. The plastic flow curves of ISO 5832-9 steel displayed in three different ways: (i) Curves with continuous softening presenting plastic instability for low temperatures and high strain rates; (ii) curves type flat, here after the peak there is little variation of stress with strain presenting softening mechanism by higher contribution of dynamic recovery at low temperatures and low and intermediate strain rates; (iii) curves with softening after the critical deformation favored by high temperatures and low strain rates. These behaviors indicate the influence of the stacking fault energy (SFE) and precipitated particles on the softening kinetics of this steel.

Aug 8, 2018