In mid-2015, SIJ Acroni, Slovenia, placed an order with Primetals Technologies to supply a new 95-ton AOD converter and a new dedusting system to its steel works in Jesenice. The new equipment was started up in April 2017, increasing annual liquid-steel production capacity by roughly 35% to 530,000 tons per year while at the same time lowering production costs and reducing emissions.
The service team of Primetals Technologies works hard to excel in a wide array of disciplines: regular maintenance work is carried out; faulty, worn-out or outdated steelmaking and rolling equipment is replaced; solutions are proposed to optimize production processes; and new and improved production and maintenance methods are successfully introduced. Detail-oriented consultation and training sessions are also in high demand, and the company’s strong emphasis on digitalization is leading to a growing portfolio of e-services available to customers. With this proven approach, even more custom-tailored service bundles are offered to improve plant performance and product quality.
For this issue of Metals Magazine, we have collected a selection of case studies that exemplify the many areas in which the Metallurgical Services department is currently active. Due to the large service portfolio, the case studies we have chosen are extremely varied in both overall size and application areas. For example, urgent repair work is featured alongside installations of state-of-the-art condition-monitoring and predictive maintenance systems, or roll-bearings are upgraded in some plants, while others receive new modernization packages. However, all of these projects have one thing in common. The core ambition that the Metallurgical Services department of Primetals Technologies has always put first is to optimally serve its customers. To achieve this goal, the company’s technology experts and service specialists listen closely to the needs of their customers and persistently strive to deliver the best-possible solutions under all circumstances. Ultimately, the goal is to create win-win situations and to build reliable long-term partnerships with customers. This commitment is clearly evident in the results delivered every day, as demonstrated by the following case studies.
CASE STUDY NO. 1
Installation of a Condition-Monitoring System Based on a Shock-Pulse Technique at LD (BOF) Converters, Brazil
After serious problems with a loose bearing in the trunnion ring of one of their LD (BOF) converters, a Brazilian producer contacted Primetals Technologies and requested a solution to avoid similar problems in the future. After a detailed consultation, Primetals Technologies recommended the installation of a condition-monitoring system that would give the customer sufficient pre-warning time before the bearing would reach the end of its lifetime. As this type of bearing moves very slowly (at approximately 1 rpm) and does not perform diagnostic checks based on a full rotation, it was a challenge to provide the bearing with a predictive-maintenance system.
Primetals Technologies offers a full range of condition- monitoring solutions for converters. These systems not only monitor the trunnion ring bearings, but also the tilting drive and the converter shell itself. One method employed in this context is that of shock-pulse technology, which is particularly suited for slowly rotating bearings. Immediately after the damaged bearing was replaced, Primetals Technologies performed regular offline shock-pulse measurements on the bearings of the trunnion ring of both converters. Having successfully monitored the condition of the bearings for almost a year, an online system was installed, which now observes not only the bearings of the trunnion ring, but also the main bearings of the tilting drive.
Data is collected with every movement of the converter. The system is integrated into the local automation system and delivers a status report to the customer’s Level 1 system after each measurement. For a more detailed analysis of individual measurements, Primetals Technologies has the ability to remotely connect to the condition- monitoring system and create a detailed report based on the findings.
The team of Primetals Technologies completed installation activities within only one working shift, which required less time than the scheduled maintenance activities.
CASE STUDIES NO. 2 AND NO. 3
Replacement of Swivel Bearing in a Ladle Turret, Poland
The replacement of a swivel bearing in a ladle turret of a continuous casting machine is a complicated undertaking. Careful planning and preparation work are required to ensure a quick and safe execution of the necessary tasks. Generally, this type of procedure is carried out only very rarely. Therefore, steel producers typically have little to no prior experience in this kind of work. To be sure that the ladle turret of a continuous casting plant in a Polish steel mill was again in perfect condition after the planned replacement time, a Polish customer contracted Primetals Technologies to exchange the bearing of their ladle turret. After a short preparation phase, onsite work commenced. The upper part of the turret had to be lifted and was kept in an elevated position for the entire duration of the work so that the old bearing could be removed and the new one inserted. When the old bearing was dismantled, an inspection of the bearing seats showed that the required tolerances defined by the bearing supplier were still within range and that no machining was necessary. The new bearing could thus be installed without further delay, and the turret was put into operation again. The work was carried out well within the scheduled completion time and without any safety incident. Since then, the turret has been flawlessly working without any reported issues. The ladle turret is now ready for a new operational campaign of at least 15 to 20 years.
Installation of Condition-monitoring System at a Ladle Turret, Poland
At the same plant, a new condition-monitoring solution for the swivel bearing of the ladle turret was installed so that accurate data about the bearing condition could be generated in the future. Condition monitoring of this type of bearing typically consists of regular grease analyses and deflection measurements.
Due to safety reasons, it is not possible to enter the turret while the caster is in operation. Therefore, the installation of the condition-monitoring system had to be coordinated and executed during a regular maintenance shutdown in the melt shop. The team of Primetals Technologies completed installation activities within only one working shift, which required less time than the scheduled maintenance activities. The streamlined project execution ensured that there were no additional losses in production time.
The new condition-monitoring system “listens” to the metal-to-metal contact that occurs when the bearing rotates. With each rotation, data is generated that is pre-processed, pre-analyzed, and finally stored in a local database. Primetals Technologies remotely connects to this database, analyzes the data on a regular basis, and deliver a report about the findings as part of a multi-year service contract.
CASE STUDY NO. 4
Urgent Reconditioning Work Performed at the Drive Housing of a Reducing and Sizing Mill, China
Primetals Technologies Services China always puts the customer and their goals first, and is ready to provide immediate support whenever required. This ambition was put to the test during the reconditioning work on one set of drive housings for a reducing and sizing mill of Yonglian Steel Group Co., Ltd.
Before the start of any on-site activities, the China Services team did precise planning and a complete risk analysis. Working day and night together with the manufacturing team, the Services team completed the reconditioning within just three days and despite a challengingly short lead time. These achievements were appropriately recognized and highly praised by the customer. The Services team of Primetals Technologies China always aims to build strong relationships with customers and to swiftly respond to their needs, as this leads to win-win situations and reliable long-term partnerships.
CASE STUDY NO. 5
Copper Coating: Improved Mold-Coating Increases Service Life of Caster Mold, Canada
A Canadian steel producer had standardized its equipment and spares to conform with the caster mold copper coating from a competitor that had been used in the producer’s plant for more than a decade. Mold coatings are designed to retard mold wear, extend the mold-service time and increase reliability. Primetals Technologies was asked to evaluate the performance of the existing mold coating with the main objective to increase the mold service life with no adverse effects on cast-slab product quality.
After a thorough chemical and mechanical evaluation of the existing coating, Primetals Technologies was able to determine the causes of the coating failure, which were the limiting factor of the mold service life. The main issue that was identified with the coating and its suitability for casting was that a ceramic coating had been used. This coating type has very low impact strength and fails by chipping, breaking and flaking as a result of extensive thermal cycling and impact loading. Based on the findings from the evaluation, Primetals Technologies was able to customize a copper mold coating that would be optimally designed and specific for this customer’s applications. Additionally, the magnitude of improvement that would result from the customization was anticipated in advance. The customer’s target was a 10% improvement in service life without a negative effect on product quality. The first trial yielded a service life improvement by more than 30%. The second trial is on target for a 50% improvement in service life.
During the reconditioning process of the used plates, Primetals Technologies discovered an additional benefit associated with the change in coating. Due to the failure mode of the previous ceramic coating, this type of coating required 20% more copper to be removed from under the ceramic coating during refurbishment, compared to the customized coating solution from Primetals Technologies. This added benefit resulted in a reduction of the amount of new copper that will have to be reapplied each year. The customer was extremely satisfied with these results, and chose to standardize its equipment and spares on the basis of the new customized coating for the respective application.
CASE STUDY NO. 6
Upgrade to Morgoil Back-up Roll Bearings for Increased Load Capacity at a Hot-strip Mill, Argentina
Motivated by the desire to produce higher-quality products at increased capacity and lower cost, Ternium- Siderar in San Nicolas, Buenos Aires, contracted Primetals Technologies to perform a back-up roll-bearing upgrade on their hot-strip mill, which had been in operation for over 50 years. The goal of the upgrade was to increase operating loads, which were outside the design rating of the original bearings, while utilizing the existing chocks and without an increase in space requirements.
When attempting to achieve the demanding levels of quality required by today’s flat-steel market, Ternium- Siderar had realized that this was not possible with the equipment it owned at the time. The problems were first identified in the form of bearing seizures in some stands, and later in that of cracks that formed in the back-up-roll neck areas due to fatigue and overload.
Engineers from Primetals Technologies worked together with engineers from Ternium in analyzing the problem and toward determining a method to upgrade the mill using the latest and most economical technology. The upgrade consisted of changing the bearings to the latest-generation Morgoil bearings: the KLX. Within the same space, this bearing allows the bearing capacity to be increased by approximately 25%. This was accomplished re-utilizing all existing chocks. The new bearing allowed for a re-design of the geometry of the back-up-roll neck, making it much stiffer than the original design and thus eliminating fatigue failures.
Furthermore, an upgrade of the hydraulic mounting and dismounting components using the Morgoil HB (hydraulic bayonet) lock was also implemented, and the latest Morgoil HD (Hydrodynamic) seals were introduced. With the Morgoil KLX upgrade, the hot-strip mill of Ternium-Siderar showed increased load capacity, allowing the company to roll products that were not even considered a few decades ago.
These case studies are recent examples of the many thousands of service projects that Primetals Technologies has implemented throughout the world over nearly four decades.
CASE STUDY NO. 7
Plant-Performance Improvements Based on Advanced Design Technology, Brazil
Primetals Technologies, in its role as a lifecycle partner for the steel industry, was contacted by CSA (Companhia Siderúrgica do Atlântico) Brazil to optimize and reduce the cooling-water consumption of its condenser and the superheated steam of its the steam-ejector vacuum pump. After an evaluation of different design proposals, the technologies were identified that would offer the best results at the lowest-possible costs. The solution was presented to the customer who then agreed to have it installed. New steam-ejector nozzles were designed and delivered to the customer’s site for installation and testing during a scheduled plant shutdown. Plant performance was evaluated before and after the new installation that demonstrated a savings of 25% in steam consumption and 20% in condenser-cooling water without negative effects on the minimum vacuum level and the pump downtime. The financial result of this improvement is savings of approximately half a million euros per year.
CASE STUDY NO. 8
Electric Arc Furnace and Ladle Furnace Upgrades, Russia
Primetals Technologies performed various upgrades on the existing electric arc furnace and ladle furnace at the Abinsk Electrometallurgical Plant (AEMZ) steel plant in Abinsk, Russia. The improvement measures on the electric arc furnace involved the replacement of existing burners with Refining Combined Burner (RCB) technology and the supply of a new oxygen-valve stand; implementation of a new programmable logic controller (PLC) based electrode regulation system, exchange of the high-current system for improved reliability; installation of a furnace- pressure measurement device, including a new off-gas flap to control the off-gas suction; and the replacement of the existing off-gas elbow on the furnace roof. The combination of these measures increased the productivity of the arc furnace to more than 200 t/h, while the respective energy consumption was reduced to 370 kWh/t, which corresponds to energy savings of 10%. Improvements at the ladle furnace comprised the replacement of the existing 2-strand wire feeder with a new 4-strand wire feeder, and the installation of a new lime-injection system. These measures enabled the customer to increase the productivity and quality of the produced steel grades at the ladle furnace.
CASE STUDY NO. 9
Electric Arc Furnace Upgrade, Germany
Primetals Technologies was contacted to conduct a revamping and upgrading project for the electric arc furnace at BGH Edelstahl Freital GmbH. Detailed project planning was carried out and plant innovations were implemented in different phases. The project comprised the substitution of major plant components; implementation of a new technological solution in the lower furnace shell; and modification of the spout-tapping-type furnace shell to a modern, high-performance eccentric-bottom- tapping (EBT) solution. Less oxide slag now escapes the furnace during tapping, which has a highly positive impact on the final steel quality and also lowers the consumption of expensive deoxidation agents. A new furnace roof was also supplied together with auxiliary parts such as ladle cars, a ladle pre-heating system and alloying systems. Additionally, dedicated risk analyses were performed to verify that all furnace components conformed with machine guidelines. The furnace upgrades were conducted at different stages to minimize any adverse effects on production output. This project highlighted the organizational and design capabilities of Primetals Technologies in electric steelmaking, which were implemented to the full satisfaction of the customer.
Installed RCB burners in the scrap-preheating shaft of the Quantum EAF at Tyasa, Mexico reduce steel skull formations, hanging-scrap issues, energy consumption and operating costs.
CASE STUDIES NO. 10 AND NO. 11
Large-scale Modernization of Electric Arc Furnace at Simec, Mexico
Grupo Simec, S.A.B. de C.V. (Simec), part of Industrias CH Group, is one of the largest steelmakers in Mexico. The company has plants in the states of San Luis Potosí, Tlaxcala, Jalisco, Baja California and Tamaulipas, as well as in Brazil and the U.S.A. Its product portfolio includes long products for the construction and automotive industries. To meet the increasing demand for long products in Mexico, in June 2015, Simec placed an order with Primetals Technologies for the modernization of a 70-ton-capacity AC electric arc furnace (EAF) at the San Luis Potosí plant. The project scope included a new design for the upper furnace shell and roof, the complete ductwork and the installation of current-conducting electrode arms. Engineering was carried out by Primetals Technologies Mexico with the support of the electric steelmaking center of competence in Legelshurst, Germany.
After the installation of the new equipment, the furnace successfully recommenced operations in October 2016. The most striking improvement was the significantly reduced tap-to-tap time, which was a result of the higher power input due to the new current-conducting electrode arms. This gave the customer the possibility to increase their steelmaking capacity from 18 heats per day up to 24 heats per day on a regular basis.
Productivity Gain Due to Installation of Refining Combined Burners in EAF at Tyasa, Mexico
Talleres y Aceros S.A. de C.V. (Tyasa), located in the southern Mexican state of Veracruz, is arguably the most innovative steelmaker in the region. Primetals Technologies had already installed a new EAF Quantum furnace with an advanced scrap-charging and scrap-preheating system at the Tyasa site. This has allowed the customer to reduce their electrical energy consumption for scrap melting by approximately 20%.
In 2016, Primetals Technologies was entrusted with an additional order to supply two RCBs (Refining Combined Burners) in the Quantum EAF. The need for these burner lances was due to scrap-hanging issues and the formation of steel skulls in the scrap-preheating shaft. Following local design modifications and installation, the RCB lances were commissioning in June 2016. After several heats, the results showed that skull formations and scrap-hanging issues in the shaft area were significantly reduced. In addition to the operational improvements, a 4% reduction in energy consumption was observed, which is equivalent to approximately 13 kWh/t per heat. Customer expectations were fully met with the supplied RCB equipment, which has further contributed to a reduction in EAF operating expenditures (opex).
Serving with solutions
The above service case studies are recent examples of the many thousands of service projects that Primetals Technologies has implemented for metals producers throughout the world over the course of nearly four decades. As a lifecycle partner for the metals industry, innovative solutions, advanced technological packages and specialized services are offered to ensure that the metallurgical facilities of customers operate reliably, efficiently and at peak performance throughout their entire lifetime.
Service specialist of Primetals Technologies, checking the alignment of stand-guide rollers with the use of the Opal system, a company-developed optical measurement tool.