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A circular steel economy based on recycling scrap is severely hampered by the increasing accumulation of Cu returning from more and more electrified products, which severely limits processing, application, and safety of steels. As of yet, no viable strategies for its removal have been developed, and the increasing Cu contamination can only be diluted with fresh primary iron. This is not only evoking CO2 emissions from conventional reduction processes, but also merely delays the problem until global demands allow for a circular steel economy. However, the ongoing transformation toward green steel making may offer pathways to overcome this complex metallurgical challenge. It is demonstrated that Cu can be effectively evaporated from Fe–Cu–O melts—representing Fe ore mixed with Cu‐contaminated steel scrap—during hydrogen plasma‐based smelting reduction. This evaporation is found to be strongly influenced by the Cu activity determined by the concentration of oxygen in the liquid, with a critical O concentration of about 22 wt%. Even without the presence of hydrogen, Cu concentrations can thereby be drastically reduced from 1 to less than 0.1 wt%. Potentials and challenges for leveraging these fundamental findings on a laboratory scale for future industrial production of green steel are outlined and discussed. [ABSTRACT FROM AUTHOR]

In this work, an object detection method using variable convolution-improved YOLOv8 is proposed to solve the problem of low accuracy and low efficiency in detecting spanning and irregularly shaped samples. Aiming at the problems of the irregular shape of a target, the low resolution of labeling frames, dense distribution, and the ease of overlap, a deformable convolution module is added to the original backbone network. This allows the model to deal flexibly with the problem of the insufficient perceptual field of the target corresponding to the detection point, and the situations of leakage and misdetection can be effectively improved. In order to solve the issue that small target detection is susceptible to image background and noise interference, the Sim-AM (simple parameter-free attention mechanism) module is added to the backbone network of YOLOv8, which enhances the attention to the underlying features and, thus, improves the detection accuracy of the model. More importantly, the Sim-AM module does not need to add parameters to the original network, which reduces the computation of the model. To address the problem of complex model structures that can lead to slower detection, the spatial pyramid pooling of the backbone network is replaced with focal modulation networks, which greatly simplifies the computation process. The experimental validation was carried out on the scrap steel dataset containing a large number of targets of multiple shapes and sizes. The results showed that the improved YOLOv8 network model improves the AP (average precision) by 2.1%, the mAP (mean average precision value) by 0.8%, and reduces the FPS (frames per second) by 5.4, which meets the performance requirements of real-time industrial inspection. [ABSTRACT FROM AUTHOR]

The current nature of steel design and production is a response to meet increasingly demanding applications but without much consideration of end-of-life scenarios. The scrap handling infrastructure, particularly the characterization and sorting, is unable to match the complexity of scrapped products. This is manifested in problems of intermixing and contamination in the scrap flows, especially for obsolete scrap. Also, the segmentation of scrap classes in standards with respect to chemical compositions is based on tolerance ranges. Thus, variation in scrap composition exists even within the same scrap type. This study applies the concept of expected value of perfect information (EPVI) to the context of steel recycling. More specifically, it sets out to examine the difference between having partial and full information on scrap composition by using a raw material optimization software. Three different scenarios with different constraints were used to appraise this difference in terms of production and excess costs. With access to perfect information, production costs decreased by 8–10%, and excess costs became negligible. Overall, comparing the respective results gave meaningful insights on the value of reestablishing the compositional information of scrap at the end of its use phase. Furthermore, the results provided relevant findings and contribute to the ongoing discussions on the seemingly disparate prioritization of economic and environmental incentives with respect to the recycling of steel. [ABSTRACT FROM AUTHOR]

This paper shows the trend of the world crude steel production in the first two decades of the 21st century. From 2000 to 2020, the world steelmaking continuously increased (total production of 28.5 billion t steel), but decreased in 2008 (1,6 %) and 2009 (7,7 %) because of the global financial and economic crises. For more than fifty years, the primary steelmaking processes are those by means of two technologies: oxidation of pig iron (product from blast furnace) in basic oxygen converters by means of technical oxygen, and smelting of old ferrous (steel scrap) in the electro arc furnaces. For the production of quality steel, the secondary metallurgy procedures (treatment of steel in ladle) play a greater role. In 2000, global steel production was 847.2 million t (basic oxygen converters share was 58.2 % and the electro arc furnaces 33.8 %), while in 2020, production reached 1.8775 billion t steel, which is an increase of 2.2 times. By 2020, the production of steel by steelmaking processes was 73.2 % by basic oxygen converters, 26.3 % by electro arc furnaces, 0.3 % by Siemens-Martin furnaces, and 0.2 % by other procedures of steel production. Primacy in steelmaking is in countries and companies from Asia (73.9 % of the world’s output). The recycling degree of steel in the period from 2011 to 2019 was 34–37 %. China is the largest world steelmaking country (since 1996). China had an increase in steelmaking of 8.3 times in the period from 2000 to 2020 (from 127.2 Mt up to 1.064 Gt). China produced 56.6 % of the world’s steel. From 2000 to 2020, a share of continuous casting was increased by about 10 % (from 87 to 96.6 %). [ABSTRACT FROM AUTHOR]

Steel and cast-iron products, due to their low price and beneficial properties, are the most widely used among metals, their consumption has become an indicator of the economic development of countries. The characteristics of iron raw materials, in relation to current metallurgical requirements, are presented in the present this article. The globalization of the trade and development of steelmaking technologies have caused significant changes in the quality of raw materials in the last half-century, forcing improvements in processing technologies. In many countries, standard concentrates (at least 60% Fe) are almost twice as rich as those processed in the mid-20th century. Methods of quality assessment have been improved and quality standards tightened. The quality requirements for the most important raw materials - iron ores and concentrates, steel scrap, major alloy metals, coking coal, and coke, as well as gas and other energy media - are reviewed in the present paper. Particular attention is paid to the quality testing methodology. The quality of many raw materials is evaluated multi-parametrically: both chemical and physical characteristics are important. Lower-quality parameters in raw materials equate to significantly lower prices obtained by suppliers in the market. The markets for these raw materials are diversified and governed by separate sets of newly introduced rules. Price benchmarks (e.g. for standard Australian metallurgical coal) or indices (for iron concentrates) apply. Some raw materials are quoted within the framework of the commodity market system (certain alloying components and steel scrap). The abandonment of the long-established system of multi-annual contracts has led to wide fluctuations in prices, which have reached a scale similar to that of other metals. [ABSTRACT FROM AUTHOR]

This study analyses the impact of the rising availability of steel scrap on the future steel production up to the year 2100 and implications for steel production capacity planning. Steel production processes are energy, resource, and emission intensive, but there are significant variations due to different production routes, product mixes, and processes. This analysis is based on the development of steel demand, using the Steel Optimization Model, which provides a region-detailed representation of technologies, energy and material flows, and trade activities. It is linked to the Scrap Availability Assessment Model which estimates the theoretical steel scrap availability. Aggregated crude steel production is estimated to evolve into an almost balanced split by 2050 between the primary production route using iron ore in the blast oven furnace and the secondary route using mostly steel scrap in the electric arc furnace. By 2060, the share of secondary steel production will exceed the share of primary steel production globally. The results also estimate a global increase in scrap use from 611 Mtonnes in 2015 to 1500 Mtonnes in 2050, with the highest growth being for post-consumer scrap. In 2050, almost 50% of post-consumer scrap is expected to be traded, with the main exporter being China and major importing regions being Africa, India, and other developing Asian countries. The results provide valuable insights on scrap availability and capacity development at the regional level for producers contemplating new investments. Regional availability, quality, and trade patterns of scrap will influence production route choices, possibly in favor of secondary routes. Also, policy instruments such as carbon taxation may affect investment choices and favor more energy-efficient and less carbon-intensive emerging technologies. [ABSTRACT FROM AUTHOR]

The present paper reports fabrication of superior steel compact using nanostructured steel powder generated from industrial steel scrap. Extra low carbon and low carbon steel powders with size of submicron were generated from industrial waste by planetary milling for 5 h. The milled powders are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and hardness. Finest particles are obtained after 3 h of milling in both cases. In case of extra-low carbon steel, cold welding and agglomeration is observed after 5 h of milling. However, in case of low carbon steel, no such phenomenon is visible after 5 h of milling. The effect of ball to powder weight ratio (BPR) is studied using BPR of 12:1 and 6:1 for low carbon steel chips by milling for 3 h. A higher yield of 94.29% is obtained when milling conducted at BPR 12:1 than 86.94% yield at BPR 6:1 after milling low carbon steel for 3 h. Lower average particle size of 5–10 μm is obtained when milling is carried out at BPR 12:1 than 15–20 μm at BPR 6:1. In case of low carbon steel, % yield increases from 94.29% to 99.14% as milling time increases from 3 to 5 h. Yttria free and 1 wt% yttria dispersed both extra-low carbon and low carbon steel powders are cold compacted and conventionally sintered at 1100 °C for 1 h. Significant improvement in the hardness was achieved through addition of small amount of yttria with both the steel powder generated from the steel scrap. [ABSTRACT FROM AUTHOR]

To investigate the potential of energy saving and emissions mitigation during 2015–2050 in China’s iron and steel industry (CISI), a comprehensive assessment approach was developed and applied on the basis of the dynamic Material Flow Analysis (MFA) model and the energy consumption and carbon dioxide (CO 2 ) emission model. Four scenarios including the business-as-usual (BAU) scenario, the structure adjustment (STA) scenario, the energy-efficiency improvement (EEI) scenario, and the strengthened policy (STP) scenario have been set to describe future energy saving and carbon mitigation strategies in relation to the development of the iron and steel industry. The modeling results show that China’s steel demand will gradually decrease from 789.35 Mt in 2013 to 440.38 Mt in 2043 and will stabilize at around 450 Mt, and the scrap resources are sufficient to support the promotion of the production structure under all four scenarios. The results also indicate that energy consumption and CO 2 emissions will gradually decline under the synergistic effect of technology promotion and structure adjustment during the period. In the short term, they will depend more on technology improvement; in the long term, particularly after 2040, promotion of the production structure adjustment will be the main force. The selected 35 energy saving technologies (ESTs) contribute to 3.01 GJ/t and 398.22 kg CO 2 /t crude steel when the discount rate of 15% is applied. [ABSTRACT FROM AUTHOR]

Three melts of ferrite-pearlitic nodular cast iron with different charge composition were used for fatigue tests. Wöhler fatigue curves and fatigue strength were obtained, and microstructure and fracture surfaces were investigated. The aim of the paper is to determine the influence of charge composition on microstructure, mechanical and fatigue properties of synthetic nodular cast irons and their micromechanisms of failure. Fatigue tests were realised at low frequency sinusoidal cyclic push-pull loading (stress ratio R = -1) at ambient temperature (T = 20 ±5°C). They were carried out with using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100 at frequency f ≈ 120 Hz. The results of fatigue tests at low frequency cyclic loading are compared with fatigue properties at high frequency cyclic loading. [ABSTRACT FROM AUTHOR]

This paper analysed CO 2 emission pathways for the Japanese iron and steel industry towards 2030, taking into account the likely development of process capacities that could flexibly adapt to a range of projected future crude steel production levels (“optimal capacities”) while maintaining minimum capacity utilisation rates. Coke and pig iron production capacities were optimised to the levels that enable flexible operation for 90–120 Mt-crude steel/y, compared to 110 Mt/y in 2010. Operational constraints were applied to the capacity utilisation rates (minimum of 85%) and the maximum use of coke and pig iron substitutes. This paper also assessed the implications of the aforementioned flexible operation across a range of crude steel production levels on the future scrap balances. This study calculated the optimal capacities for coke ovens and blast furnaces in 2030 to be 29 Mt-coke/y (compared to 43 Mt/y in 2010) and 83 Mt-pig iron/y (compared to 90 Mt/y in 2010). Under these optimal capacities and the aforementioned range for crude steel production levels, the projected total CO 2 emissions were 4–21% below 2010 levels. If the 2030 production level remains at 105 Mt/y, which equals the 2015 production level and the 1973–2015 average, the total emissions will be 9–16% below 2010 levels, depending on the level of emissions reduction effort. These results indicate that the industry is likely to considerably overachieve its voluntary emissions reduction target for 2030 (0.1% below 2010 levels). Moreover, it was found that the lifetime extensions for existing blast furnaces and coke ovens have limited impact on CO 2 emissions while significantly reducing the investment needs. The study also showed that the low crude steel production (90 Mt/y) combined with high pig iron and coke consumption levels to maintain minimum capacity utilisation rates may lead not only to an increase in specific CO 2 emissions per tonne of crude steel but also to a net export of obsolete scrap up to 17 Mt, which is nearly twice the historical high. Towards 2030, Japan would need to consider not only opportunities to maximize the use of steel scrap but also the development of an extended steel scrap trade infrastructure. [ABSTRACT FROM AUTHOR]

The grey irons prepared by adding steel scrap as main raw material were designed. Effect of the steel scrap content on the microstructures, mechanical properties and fracture mechanisms of the HT250 grey irons was studied. The results show that as the steel scrap content increased, the microstructures of the grey irons are improved, and the mechanical properties of the grey irons are therefore increased. The grey iron by adding 100 wt-% steel scrap has the optimal microstructure composed of the small and curved graphite flakes, the refined pearlite colonies and the dispersed MnS and TiN inclusions, also, it has the highest mechanical properties and comprehensive performance. [ABSTRACT FROM PUBLISHER]

An up-to-date techno-economic assessment was conducted on CO 2 emissions reduction potential in the Japanese iron and steel industry for 2030. The following mitigation measures were investigated: (i) maximized installation of best available technologies (BAT scenario), (ii) increased use of coke substitutes in blast furnaces, and (iii) increased use of obsolete steel scrap. For measure (iii), this study assessed the obsolete scrap use in the integrated steelmaking (BF-BOF) route, rather than increasing steel production from the electric arc furnace (EAF) route. CO 2 capture and storage (CCS) was not considered due to large deployment uncertainty. The results showed that 20 Mt–CO 2 of emissions reductions, equivalent to 12% of the industry's total emissions in 2010, can be achieved in 2030 compared with a frozen technology scenario. More than 9 Mt–CO 2 reduction was attributable to the enhanced use of obsolete scrap in the BF-BOF route. Consequently, the industry's emissions reduce by about 7 Mt–CO 2 or 4% below 2010 levels. Almost all domestically recovered obsolete scrap can be fully consumed solely by increasing the scrap use in basic oxygen furnaces (BOF). Moreover, the increase in average copper concentration in the BF-BOF steel due to the increased obsolete scrap use was found unlikely to limit the production of high-quality steel products. In comparison with a scenario that only considered measure (i) and assuming a 15% real interest rate, CO 2 mitigation cost curves for 2030 showed that the CO 2 mitigation costs were below US$ 2010 20/t-CO 2 for measure (ii) and around US$ 2010 110/t-CO 2 for measure (iii). Compared to the marginal abatement costs calculated for 2030 to reduce Japan's GHG emissions by 20%–25% from 1990 levels (about US$ 2010 67–640/t-CO 2 ) reported in the literature, all three measures may become economically viable. The increased use of obsolete scrap in the BF-BOF route can become an interesting option for Japanese steelmakers to stimulate the steel scrap market and achieve economical global CO 2 emissions reductions while maintaining international competitiveness in the midterm future. [ABSTRACT FROM AUTHOR]

The abnormal corrosion of hot iron ladles was investigated. The performance, the composition and the structure of bricks for the hot iron ladles were analyzed. The results show that (1)compared with the alumina-silicon carbide-carbon bricks for the ladle bottom, those for the ladle wall have more pyrophyllite and the Al2O3 content of 36.32 mass%; their bulk density, apparent porosity and compressive strength are all lower than the requirement of industry standards; they have poor oxidation resistance and are oxidized to form a porous layer during service, which loosens the brick lining structure thus leading to fracture, local wear and structural damage of bricks; (2)without heating, steel scrap is not completely melted, resulting in slag or steel attachment at the mouth or the bottom of ladles thus increasing damage of ladles; (3) and the residual bricks react with the attached slag to form low melting point phase affecting their hot properties. The refractories for the lining of hot iron ladles must be improved in combination with process changes, not entirely by raw materials replacement to reduce costs. [ABSTRACT FROM AUTHOR]

In the context of a cooperation project a process for the acid dezincification, the so-called bypass predezincification, has been developed to industrial maturity. The process is based on the inhibitory effect of wash- and draw oils. These protective oils are preventing the leaching of iron in combination with zinc. The industrial efficiency has been verified by setup and operation of a dezincification pilot plant with a nominal throughput of 24 t d-1. The current throughput could be increased to 100 t d-1. A dezincification grade up to 99 % could be obtained for electroplated and hot dipped scrap sheets as well as mixtures of both. In comparison to the common dezincification process route energy saving by the factor of 50 and a CO2 reduction by a factor of 40 is achieved. [ABSTRACT FROM AUTHOR]

In the production and transportation of oil and gas there are many common problems of erosion-corrosion. The velocity of the flow and the drag of solid particles within the oil transported by pipelines are critical factors in the process of deterioration of low-carbon steels in the presence of CO2. In this research, tests of erosioncorrosion were performed in a cell with a dynamic system of rotating cylinder electrodes at speeds between 1 and 3 m / s, particle sizes between 300μm and 50μm at concentrations between 1 and 9% by weight. Techniques of direct current and alternating current were used to determine the corrosion rate under the conditions evaluated and determine the influence of the particles of sand and the speed of rotation on the corrosion rate of steel. A mathematical relation between the corrosion and system variables was calculated. [ABSTRACT FROM AUTHOR]

The paper discusses the use of a secondary smelting technology for reinforcing steel (rebar) production at Baku Steel Company, LLC, noting the feasibility of adding metallized pellets to the furnace charge consisting of scrap metal and other manufacturing waste products. The addition of such pellets enhances the process of melting the charge in an electric arc furnace (EAF). The process utilizes direct-reduced iron (DRI) and hot-briquetted iron (HBI) pellets. The status of metallized pellet production in different countries was analyzed. The characteristics of DRI and HBI pellets were compared. The results of two EAF melting runs conducted at Baku Steel Company, LLC are presented. It is shown that the use of metallized raw materials in the EAF charge resulted in 87 to 90 % yield of usable metal. The rebar stock obtained from this steel meet the standard strength requirements. Various EAF pellet-charge layouts are demonstrated, noting the importance of continuous loading of the charge materials through the furnace roof. Alternatively, the pellets can be loaded into EAF through an opening in the furnace wall. At Baku Steel Company, LLC, pellets are loaded through the furnace port. It is shown that the mixture of materials is supplied to a bunker, and then loaded into the furnace using a belt. [ABSTRACT FROM AUTHOR]