Metal Processing Research Articles

Application of The Rapid Entire Body Assessment (REBA) Method to Improve Work Safety in The Automotive Spare Parts Industry

This industry consists of companies engaged in metal processing and workmanship. Companies often receive complaints from employees concerning pain or discomfort in their bodies, causing diseases such as low back pain and myalgia. The risk of accidents occurring at work is inseparable from the work done. Work-related accidents can occur due to several factors, including unsafe action. One cause of unsafe actions can be found in various unsafe work postures that workers assume. Therefore, the purpose of this study is to evaluate the posture of these workers so that it can improve their safety and health. This research was conducted by identifying occupational risks workers face and examining work performed in stamping products. The production section consists of six stations: material handling, stamping, welding, hemming, painting, and packing. The work risks run by workers have been identified using the Nordic Body Map (NBM) questionnaire and interview methods. As for the identification of the type of work carried out by evaluating work postures, the Rapid Entire Body Assessment (REBA) method has been employed. The risk level of accidents is also used for the selection of activities to be improved to minimize the level of injury risk caused by work postures that have been assumed, and in order to improve the safety and health of the workers. Improvements made are in engineering, such as manufacturing of assistive devices, and management engineering, such as providing directions that can improve the specific work posture used. Calculations are based on simulations performed with tools conducted with suggested postures by evaluation using the REBA method. Based on the results of REBA calculations, the resulting risk is lower than the one caused by the previously assumed posture, namely medium and low.

Mixed lead sources in tin metal: Implications for using lead isotopes to study tin artifacts

Methods for provenancing copper, lead, and silver using the isotopic composition of lead are well-established. Lead isotope analysis holds promise for the study of tin metal as well, as long as one accounts for the U-Th-Pb systematics of cassiterite (SnO2) and chaîne opératoire of tin production. Although Precambrian cassiterite may contain 10s of ppm Pb or more (predominantly radiogenic 206Pb), Phanerozoic examples typically contain only a few parts per million Pb. However, all but one of the 133 raw tin ingots excavated from European Bronze Age shipwrecks contains more Pb than could have come from cassiterite alone, as do six of the twelve analyzed tin objects interpreted to have been derived from the ores of southern Africa. Accordingly, almost all tin objects must contain Pb from external cassiterite sources and interpretation of LIA must account for this contamination. The nature of the contaminant (sulfides, U-Th-bearing minerals, silicates) can be inferred from patterns in Pb concentration and LI values. The 3 major sources of Pb that can typically be identified in tin artifacts are original Pb from the tin ore, radiogenic Pb produced in-situ due to U decay, and external Pb added during the cassiterite smelting and ingot production. As cassiterite has high U/Pb but low Th/Pb, the 208Pb/204Pb may be representative of the initial Pb incorporated in the mineral. This is assuming either that no external Pb is added during the ore processing or that the added Pb is from coeval sulfides from the same Pb ore provenance. In such cases 208Pb/204 Pb can be used to estimate a Pb model age, which in turn can be used for provenance estimate of the ingots. If the addition of Pb is from U-Th-mineral contaminants to the ore concentrate, then this will also increase 208Pb/204Pb and point to erroneously young model Pb ages. In such cases, the problem would be evident in positively correlated values of 206Pb/204Pb and 208Pb/204Pb. If Pb concentrations are above a certain threshold (approximately 5 ppm). LIA typical common Pb isotope ratios will be clear indication that external, non-cassiterite Pb, is added to the tin artifact. This tin could be from impurities in the ore (e.g., inclusions in cassiterite, impurities in the ore concentrate, or added during ore smelting and/or metal processing. Overall, elevated Pb concentrations accompanied with non-radiogenic Pb isotopes typical for common Pb, is a clear indication that significant amount of external (contaminant) Pb is added to the tin artifact.

Assessment of heavy metal contamination in the surface sediments, seawater and organisms of the Pearl River Estuary, South China Sea

Coastal heavy-metal contamination poses significant risks to marine ecosystems and human health, necessitating comprehensive research for effective mitigation strategies. This study assessed heavy-metal pollution in sediments, seawater, and organisms in the Pearl River Estuary (PRE), with a focus on Cd, Cu, Pb, Zn, As, Hg, and Cr. A notable reduction in heavy metal concentrations in surface sediments was observed in 2020 compared to 2017 and 2018, likely due to improved pollution management and COVID-19 pandemic restrictions. Spatial analysis revealed a positive correlation between elevated heavy-metal concentrations (Cu, Pb, Zn, Cd, and As) and areas with significant human activity. Source analysis indicated that anthropogenic activities accounted for 63 % of the heavy metals in sediments, originating from industrial effluents, metal processing, vehicular activities, and fossil fuel combustion. Cd presented a high ecological risk due to its significant enrichment in surface sediments. Organisms in the PRE were found to be relatively enriched with Hg and Cu, with average As concentrations slightly exceeding the Chinese food-health criterion. This study identified high-risk ecological zones and highlighted Cd as the primary pollutant in the PRE. The findings demonstrate the effectiveness of recent pollution control measures and emphasize the need for ongoing monitoring and mitigation to safeguard marine ecosystems and human health.

The shoulder effect in the stagnation zone for temperature-controlled jet impingement transition boiling of submerged dielectric fluid

Two-phase jet impingement is capable of high heat transfer coefficients and high boiling critical heat flux (CHF) limits, making it a suitable technology for electronics immersion cooling applications. Previous studies have focused on the heat-flux-controlled nucleate boiling performance of an impingement jet up to the CHF. Exploration of other boiling regimes that occur under temperature-controlled surfaces is of equal fundamental importance. It has been shown for free jets that a high and consistent heat flux can be dissipated over a wide range of surface superheats in the transition boiling regime when the surface is temperature-controlled. This so-called “shoulder effect”, or heat flux shoulder, is strongest in the stagnation zone, directly beneath the jet. It has only observed using free jets of water as the cooling for interest in metals processing applications. To exploit operation in this unique boiling regime for potential applications in immersion cooling of electronics, the occurrence of this shoulder effect, as well as means for estimating the shoulder heat flux across different operating conditions, must be investigated for submerged jets and dielectric coolants. In this work, temperature-controlled submerged jet impingement is experimentally characterized using HFE-7100. A copper heater sized to be completely covered by the jet stagnation zone is increased in surface temperature via a PID controller, which allows for steady-state, temperature-controlled data to be acquired. The boiling curves, including CHF and shoulder heat flux, are measured for 0.5–3 m/s jet velocities and 5–30 K inlet subcooling. The shoulder effect is shown to exist in these conditions and high-speed imaging reveals that the shoulder heat flux effect is an enhanced film-like mode of transition boiling. It is observed that there is a proportionality between the CHF and the shoulder heat flux for the conditions investigated. The measured trends and dependencies of the shoulder heat flux on inlet subcooling and jet velocity are used to assess available predictive tools.

High precision blood lead radiogenic isotope signatures in a community exposed to Pb contaminated soils and implications for the current Pb exposure of the European population

Our study provides the most comprehensive dataset for high-precision radiogenic isotopes of lead (Pb) in blood for the western European population. It investigates their potential for elucidating the contribution of soil Pb to blood Pb using a human biomonitoring survey involving 81 adults and 4 children living in the urban area of Liège (Belgium). Soils in the area show moderate (median of 360 mg/kg) to high (95th percentile of 1000 mg/kg) Pb concentrations, due to former metal processing activities. Blood lead levels (BLL) measured in the study population are, on average, quantitatively consistent with a ∼ 20 % increase due to the exposure to Pb from soils, as estimated by a single-compartment biokinetic model. Consistently, its isotopic composition does not represent an endmember that fully accounts for the variability of Blood lead isotope (BLI) compositions measured in the study population. While some individuals show more thorogenic BLI ratios (relatively more enriched in 208Pb), which could be consistent with a greater exposure to local soils and/or by their country of birth, the BLI data mostly follow a trend roughly parallel to the European Standard Lead Pollution (ESLP) line, within the European leaded gasoline field, even two decades after the withdrawal of this source. Differences in BLI are probably associated with factors related to the presence of Pb in dwellings (pipes, paint) and drinking water distribution system, suggesting that the anthropogenic Pb in use, relevant to human exposure, may contain ore components of different origins, including the Australian Pb ore signature.

Virtuous Legislation: The Royal Decree for the Sustainable Management of the Woods of Serra San Bruno, Stilo, Mongiana, and Ferdinandea

The Saving Forests Decree of 1773, issued by Ferdinand IV of Bourbon, marked a fundamental step in the sustainable management of the forests of the Serre Calabresi. Metal mining and processing in the region dates back to ancient times, with Greek colonies exploiting local resources for tools and coins. With the arrival of the Normans, the mines became strategic and were granted to the Carthusian monks, and the Norman smelting furnace improved military production. Under Ferdinand II, the Ferdinandea foundry reached its peak, producing high-quality weapons. The Salvaboschi decree demonstrated a growing awareness of the need to balance industrial needs with environmental protection. This study analyzes the decree, examining how its provisions are in line with modern environmental protection laws. The analysis of this study focuses on the provisions of the Salvaboschi decree and their compliance with current environmental protection laws. The main objective of the decree was to implement sustainable forestry practices through regulated logging cycles to prevent deforestation and promote natural regeneration. Analysis of the law reveals its progressive nature and its conformity with modern principles of environmental conservation. This historic legislation testifies to the early recognition of the importance of sustainable resource management and the foresight of the Bourbon administration in implementing practices that would benefit both the environment and industrial development. Through the study and analysis of the rules present in the document, it was possible to make significant comparisons with the laws in force. The decree demonstrates considerable foresight in the protection of natural and forest heritage. This document represents an important step towards environmental protection, highlighting a concrete and proactive commitment to the protection of natural resources. The ability to compare existing regulations with new provisions offers a clear and in-depth perspective on legislative evolution in environmental matters, confirming the importance of regulatory updates to address contemporary ecological challenges.

Microbiodiversity Landscape Present in the Mine-Tailings of the “Sierra de Huautla” Biosphere Reserve, Mexico

Large-scale mining activities generate significant amounts of waste that accumulates in the environment. These wastes, known as mine tailings, contain high levels of heavy metals, posing risks to human health and causing severe damage to ecosystems. In this study, we determined the heavy metal content of mine tailings in the Sierra de Huautla Biosphere Reserve (REBIOSH), Mexico, and investigated their effect on microbial composition. One of the sites historically contaminated with metals was sampled in three different locations, labeled S1, S2, and S3. A fourth site free of heavy metals (S4) was also used as a control. Our results showed high levels of As, Pb, Cd, and Ag, potentially dangerous metals that exceed thresholds set by international regulatory agencies. Metal contamination indices indicated moderate to extreme enrichment for As, Cd, and Pb, posing potential ecological risks. A metagenomic study of mine tailings showed a core specie-specific microbiome covered by Sinimarinibacterium flocculans, Jiangella anatolica, Thiobacillus denitrificans, Fontimonas thermophile, Sphingomonas koreensis. These may be associated with the processing of heavy metals. A comparative study using the ALDEx2 revealed that less represented species like Variovorax paradoxus, Usitatibacter rugosus, Usitatibacter palustris, Sphingosinicella microcystinivorans, Sphingobium yanoikuyae, and Stella humosa may serve as microbial markers in metal-contaminated environments. In addition, we detected rare or low-abundance species belonging to the phylum Armatimonadota, Candidatus Melainobacteriota, Candidatus Saccharimonadota, Chlamydiota, Deinococcota, Elusimicrobiota, Bacillota, Rhodothermota and Verrucomicrobiota, which could play an important role in ecosystems contaminated with heavy metals. Also, we found site-specific taxonomic representatives such as Nitrososphaera gargensis and Nitrospira nitrificans dominating the S3 ecosystem; Ensifer aridi (S2 and S1), N. nitrificans (S2), while Reyranella soli dominate the S1 soil. These organisms could be crucial for nitrogen access in oligotrophic environments and underscore the adaptability of microbial life to extreme conditions. This is the first comprehensive study of the microbial composition in this important ecological site of the Mexican geography and can provide future guidance for the management and biological treatment of mining wastes.

Micromachined structures decoupling Joule heating and electron wind force

Microstructural changes in conductive materials induced by electric current treatments, such as electromigration and electroplasticity, are critical in semiconductor and metal processing. However, owing to the inevitable thermal effect (Joule heating), the athermal effect on microstructural modifications remains obscure. This paper presents an approach of utilizing pre-micromachined structures, which obstruct current flow but maintain a thermal history similar to that of the matrix, effectively disentangling the thermal and athermal effects. A duplex stainless-steel material is selected to validate the feasibility of this method. Microstructural characterizations show that the athermal effect, especially the electron wind force (EWF), primarily governs the element diffusion and phase transformation in this study. Moreover, many σ phases (Cr-enriched) are precipitated in the micromachined structures, whereas no precipitation occurred in the matrix, suggesting that the directional EWF disrupts the Cr aggregation caused by Joule heating. Furthermore, we present a critical formula for determining the dimensions of micromachined structures of commonly used metallic materials. The proposed method may serve as an effective and powerful tool for unveiling the athermal effect on microstructural alterations.

Contaminant and Assessment of Heavy Metals in Maninjau Lake, West Sumatera, Indonesia

Purpose: Water is an important fundamental resource to support human, animal and plant life. Global reports highlight widespread contamination of water sources due to various human activities. The high level of anthropogenic activity in the Lake Maninjau area, both in agriculture, animal husbandry and settlements, has an impact on decreasing the quality of the lake as indicated by the quality of the sediment and lake water. The research aims to evaluate heavy metal concentrations in sediments and heavy metal processing strategies. Theoretical Framework: Lake Maninjau is one of the lakes in Indonesia that experiences pollution. Recently, this lake has become one of the priority lakes to reduce high levels of pollution (Ministry of the Environment, 2011). The source of Lake Maninjau pollution comes from floating net cages, agriculture, settlements and livestock. This is shown by the accumulation of heavy metals in waters and sediments which is important information for the survival of fish, humans, plants, microorganisms and other aquatic ecosystems (Wibowo et al. , 2022a). Method: The five distinct sample locations were chosen to represent various activities within the Maninjau Lake region, as outlined in Figure 1 and Table 1. Sediment was taken at the surface at a depth of 0-10 cm. samples were processed and analyzed at the P3IN soil science laboratory, Andalas University, as well as assessing sediment quality through Geoaccumulation (Igeo), enrichment factor (EF), pollutant load index (PLI), contamination factor (CF), and potential ecological risk (PER) in five location of Lake Maninjau. Results and Discussion: The results of the research showed that Cu concentrations varied from 0.195 mg/kg to 0.290 mg/kg, with a moderate average of 0.246 mg/kg. Pb metal ranges between 0.325 mg/kg-0.412 mg/kg, with an average of 0.356 mg/kg. Cd metal 0.301 mg/kg- 0.365 mg/kg. The Igeo values for the metals Cr, Cd, Pb, and Cu at the five locations show Igeo < 0, meaning they are not contaminated with heavy metals. The Potential Ecological Risk Index (PER) ranges from 14.8303-19.0094, which shows the low potential ecological risk related to heavy metal pollution Research Implications: It is hoped that this research can help stakeholders in managing the Maninjau Lake ecosystem against potential heavy metal contamination that threatens the lake ecosystem Originality/Value: The use of combination or hybrid technologies to treat heavy metals from wastewater is an effective solution, but it is important to carefully consider and mitigate potential negative impacts on the environment and human health.

Outcomes and Conclusions from the 2022 AM Bench Measurements, Challenge Problems, Modeling Submissions, and Conference

The Additive Manufacturing Benchmark Test Series (AM Bench) provides rigorous measurement data for validating additive manufacturing (AM) simulations for a broad range of AM technologies and material systems. AM Bench includes extensive in situ and ex situ measurements, simulation challenges for the AM modeling community, and a corresponding conference series. In 2022, the second round of AM Bench measurements, challenge problems, and conference were completed, focusing primarily upon laser powder bed fusion (LPBF) processing of metals, and both material extrusion processing and vat photopolymerization of polymers. In all, more than 100 people from 10 National Institute of Standards and Technology (NIST) divisions and 21 additional organizations were directly involved in the AM Bench 2022 measurements, data management, and conference organization. The international AM community submitted 138 sets of blind modeling simulations for comparison with the in situ and ex situ measurements, up from 46 submissions for the first round of AM Bench in 2018. Analysis of these submissions provides valuable insight into current AM modeling capabilities. The AM Bench data are permanently archived and freely accessible online. The AM Bench conference also hosted an embedded workshop on qualification and certification of AM materials and components.

Possibility and pathways of China's nonferrous metals industry to achieve its carbon peak target before 2030: A new integrated dynamic forecasting model

The Chinese government has mandated that the nonferrous metals industry (NMI) achieve carbon peaking before 2030. Consequently, nonscientific mitigation measures, such as indiscriminate closure of production lines, have been implemented. An appropriate carbon peak pathway must be developed NMI. This study designs three carbon peaking pathways for two subsectors within the industrial chain of the NMI according to the latest industry policies and industry characteristics. Subsequently, a novel integrated dynamic assessment model is constructed in this study to evaluate the probability of carbon peaking under various pathways and choose an appropriate one. Results indicate that: (1) Under the baseline development pathway, the likelihood of meeting the target as anticipated is 61.6 % for the nonferrous metal mining and processing industry (MS) and 9.9 % for the nonferrous metal smelting and refining industry (SS). (2) The low-carbon scenario is the most suitable development path for both subsectors. Under this pathway, the likelihood of MS and SS reaching their targets on time increases to 100 % and 87.4 %, respectively. MS likely peaked in 2013, with a peak at 28 Mt. SS is projected to peak in carbon emissions by 2025, with the highest probability of peaking between 417.6 Mt and 424.5 Mt. If no fluctuations will takes place during the implementation of low-carbon policies, then the peak would occur at 423.9 Mt (3) In this pathway, the industrial value added and energy intensity have the greatest influence on the probability of missing the deadline. This study enriches prediction methods for CO2 emissions and offers guidance to the Chinese nonferrous metal industry for effectively achieving the peak carbon target.

Procurement practices and operational performance: a study of linear and curvilinear relationships in a developing economy

PurposeWhile operational performance is important for a company's competitiveness and profitability, this study claims that procurement may be required to drive operational performance. This study aims to focus on how procurement practices is related to operational performance among selected manufacturing firms.Design/methodology/approachThe model was tested on a sample of 329 manufacturing firms in clothing and textiles, chemicals and plastics, food and beverages processing, wood processing, metal processing and pharmaceutical manufacturing industries in a developing economy.FindingsThe results indicate that firms with higher and optimal level of procurement practices achieve higher levels of operational performance. Regardless of the H1 rationale, this study suggests that increasing procurement techniques has a limit in terms of improving operational performance. This study establishes that extreme level of procurement practices is associated with decreasing operational performance.Practical implicationsThis study calls attention to how managers can guide organizations in refining their procurement strategies and practices; there is the need to strive to strike a balance between diversification and efficiency in procurement.Social implicationsManufacturing firms are often integral parts of local communities. The decisions they make regarding procurement practices can impact the economic health of these communities. Striking a balance between diversification and efficiency can contribute to sustainable business practices that benefit both the company and the local community.Originality/valueAs the main contribution, this study brings the additional perspective that extreme level of procurement practices is associated with decreasing operational performance.

Metal Material Processing Using Femtosecond Lasers: Theories, Principles, and Applications.

Metal material processing using femtosecond lasers is a useful technique, and it has been widely employed in many applications including laser microfabrication, laser surgery, and micromachining. The basic mechanisms of metal processing using femtosecond lasers are reviewed in this paper and the characteristics and theory of laser processing are considered. In addition to well-known processes, the recent progress relating to metals processing with femtosecond lasers, including metal material drilling, metal ablation thresholds, micro/nano-surface modification, printed circuit board (PCB) micromachining, and liquid metal (LM) processing using femtosecond lasers, is described in detail. Meanwhile, the application of femtosecond laser technology in different fields is also briefly discussed. This review concludes by highlighting the current challenges and presenting a forward-looking perspective on the future of the metal laser processing field.

Characteristics of Pollution and Microbial Community Structure in the Antimony Mining Area of Longnan, Gansu Province

Antimony （Sb） is a major pollutant that poses a serious threat to the environment in the mining and processing of nonferrous metals, coexisting with sulfide and oxide of arsenic （As）. Microorganisms play an important role in the migration, transformation, and repair of metals in soil. The ecological effects of bioavailable Sb and As on the microbial community in antimony mining areas（mining and smelting areas）are still poorly understood. The Wenzel method and high-throughput 16S rDNA amplicon were used to characterize soil pollution characteristics in different functional areas, and the relationship between the bacterial community and bioavailable concentrations have been investigated comprehensively. The results showed that： Chemical speciation of Sb and As were amorphous, and poorly crystalline hydrous oxides of Fe and Al （F3） &gt; well-crystallized hydrous oxides of Fe and Al （F4） &gt; residual phases （F5） &gt; specifically adsorbed （F2） &gt; non-specifically adsorbed （F1）. According to the estimation of the potential ecological risk index （RI） and geo-accumulation index （Igeo）, the Sb pollution degree was： smelting area &gt; mining area &gt; contrast area, in which the smelting area showed serious pollution, and the mining area showed moderate to severe pollution. The As pollution degree was： mining area &gt; smelting area &gt; contrast area, in which the mining area and smelting area showed moderate to severe pollution. High-throughput 16S rDNA amplicon showed that Proteobacteria was the most abundant phylum in mining and smelting areas； Kaistobacter, Pseudomonas, Sphingomonas, and Lysobacter were the most abundant microbial genera； Geobacter and Luteolibacter had a high LDA score in mining areas； and Thiobacillus had a high LDA score in antimony-contaminated areas. Spearman correlation analysis, variation partitioning analysis （VPA）, and random forest （RF） analysis showed that Sb, As, bioavailable antimony [Sb （Bio）], and bioavailable arsenic [As （Bio）]were the main factors affecting the microbial community structure in different functional areas of antimony ore. Redundancy analysis （RDA） indicated that Sb and its bioavailable concentrations showed uniformly negative associations with the relative abundance of bacteria Nitrospirae and showed a significant positive correlation with Thiobacillus （P<0.05）. The in-depth research on the ecological effects of bioavailable Sb and As on the bacterial community provides references and new perspectives for environmental monitoring and management.

The Prediction of Failure in the Gas Filtration System in Low-Pressure Carburising Furnaces

Predictive maintenance is one of the key aspects of Industry 4.0. The article presents the results of experimental tests of nitrogen purification filters in the installation of a low-pressure, metal processing device. The aim of the research was to develop a predictive algorithm for making decisions regarding the replacement of used filters, based on flow analysis and measurement of the pressure difference in front of and behind the tested filter. For the purposes of the research, a special test stand was constructed, which made it possible to determine the operating characteristics of three selected filters. Based on the tests carried out, the limit characteristics of the parameters measured were determined, identifying the need to replace filters in the gas installation.

RISKS OF INJURY AND HEALTH DAMAGE WHEN USING BLACKSMITH EQUIPMENT

The article identifies the need to analyze the risks of injury and health damage when using blacksmith equipment which is due to the implementation of the latest technologies for the successful economic development of the country, the introduction of a risk-oriented approach, as well as the implementation of international standards in all sectors of the economy. It was noted that international standards are based on the use of a risk-oriented approach in solving issues of safety and occupational health of employees. Therefore, this requires the implementation of new approaches and the formation of new relationships in particularly dangerous areas of production. The general state of occupational injuries and deaths of workers in Ukraine for the period starting from 2022 to 2024 (four months of the current year) is given. The given data indicate an increase in the number of accidents at work which is further complicated by the war. These data indicate an increase in injuries at work which is a bad indicator and the need to implement modern risk-oriented technologies in the metallurgical industry. Analyzing the situation in the metallurgical industry where blacksmith equipment is widely used it should be noted that the main causes of injury and death of workers are organizational. This proves that the risk management system at enterprises is imperfect and needs to be improved and brought into line with international standards. Scientific approaches to determining the risks of injury and damage to the health of workers (operators) when using blacksmith equipment are considered. It is shown that modern technologies of metal processing by forging as one of the methods of pressure processing, use more and more robotic complexes which have risks associated with the organization of work in the conditions of the probability of physical impact of their individual elements and substances on workers. The dangerous and harmful factors that accompany the work of operators when using the MKP10 forging manipulator are given. The operation of the MKP10 manipulator is considered as an example. Tables and diagrams of the manipulator are made in accordance with the DSTU ISO 12100:2016 standard. The calculation of the risk indicator of the MKP10 manipulator was also performed which showed that the risk is average in terms of its damage and probability indicators. This leads to the need to apply risk management to control such risk and reduce it to acceptably small values.

The Business Model of a Circular Economy in the Innovation and Improvement of Metal Processing

The Business Model of a Circular Economy in the Innovation and Improvement of Metal Processing

Simplification of the Acidithiobacillus ferrooxidans Culture Process for Expanding the Field of Biomachining.

Biomachining is an eco-friendly metal processing method with broad application potential. Nevertheless, the bacterial culture methods that are currently involved in biomachining require the intensive use of chemical reagents, especially FeSO4, specialized equipment, and professional-level skills in the field of biology. Herein, the differences between two cultures with and without sterilization were evaluated. Acidithiobacillus ferrooxidans was cultured with iron instead of FeSO4 in the culture medium. The chemical and biochemical parameters of the culture were analyzed by studying the area of exposed iron and continuously regulating the pH. Eliminating the sterilization and sterile inoculation of the medium is feasible for culturing A. ferrooxidans. The key to achieving a high bacterial density in culture with iron was to maintain the solution pH. The possibility of mass culturing A. ferrooxidans with steel cuttings was evaluated in a custom bioreactor, and the bacterial concentration reached 9 × 107 cells/mL.

Components of the development of methods for calibrating rollers for rolling channels based on changed non-uniformsty of deformation

Introduction. In metallurgy, the final stage of production is metal processing in rolling shops. The main component of the development of technologies for rolling graded profiles is the calibration of rolls. 90% of the steel that is smelted is processed by rolling. Rolling mill calibration methods are constantly being improved. Calibration methods are used in which there is a significant uneven deformation of the profile elements, which leads to rapid wear of the rolls and an increase in costs. Formulation of the problem. It is necessary to develop a method of calibrating rolls in the production of channels based on the reduction of deformation unevenness. Goal. The purpose of the article is to analyze the methods of calibrating rolls for the production of channels with an indication of their advantages and disadvantages and to justify the application of the components of the developed method of calibrating rolls based on the reduction of unevenness of deformation. The results. The analysis of various methods of calibrating channel rolls showed that the smallest unevenness of deformation is present in the method of rolling by the bending method. The greatest uniformity of deformation along the width of the profile is achieved, the wear of the rolls is reduced in connection with ensuring a minimum difference in the diameters of the rolls in the gauge, and energy costs are reduced. To reduce the uneven deformation of the metal, it is suggested to use a rectangular blank or strip. Scientific novelty. For the first time, the methods of calibrating rolls for channel rolling were analyzed in detail. To reduce uneven deformation of shelves and flanges in the center of deformation in the gauge, it is proposed to use the bending calibration method. It is proposed to use strips as a blank for the first time. Practical meaning. The application of channel rolling technology based on the developed method of calibrating rolls with reduced unevenness of deformation in the first passes allows to reduce the cost of products and give an economic effect

Study of the System Response Analysis for the Eddy Current Test Crack Assessment on SS 316 Metal Arc Welding Joints

In modern industry, accurately assessing metal coupling by welding is critical. Given its reliability and other advantages, the eddy current test (ECT) is essential and commonly used in metal processing, especially welding. The classical ECT assesses the presence of discontinuities in the structure by monitoring the change in the probe's impedance. According to the wireless power transfer (WPT) theory, ECT members will exchange power wirelessly through mutual induction determined by inductance, capacitance, and resistance (LCR). The cracks will affect the mutual induction in the ECT's power exchange. Since LCRs are impedance components, the crack in the target will affect the system’s mutual induction, as it did to the impedance in the classical ECT. This study applies the WPT model of ECT, implements system response analysis to assess cracks, and compares the results with classical ECT. The test piece is a metal arc-welded joint on SS 316 with an implanted notch on the welded joint to simulate the crack. A series of initial tests were performed to ensure the test piece was defects-free. Simulation and a frequency scan were performed to acquire a safe measurement. The result was that both the classical ECT and the system’s response analysis successfully assessed the presence of cracks with excellent agreement. The system’s response analysis yields a more rapid result than classical ECT.