Metalworking Industry Research Articles

Women Workers in Essential British Metal and Chemical Industries During the Second World War and the Immediate Post-War Years

Women Workers in Essential British Metal and Chemical Industries During the Second World War and the Immediate Post-War Years

CAD-CAE-CAM technology in the manufacture of a 3-jaw independent chuck prototype in acrylic

The use and application of CAD, CAE, CAM systems are increasingly necessary in the industry, (Arriaga Segundo, 1999) To meet the needs of the accelerated industrial transformation that is taking place in industrially developed and developing countries, it is essential that those involved in the Mexican metalworking industry. In the technological area, there is a machining center for 4 axes, of which only 3 are used, due to not having a chuck for the 4th axis, which is necessary to manufacture more complex parts, and to prepare future engineers in the use of this technology. For this reason, an acrylic mandrel prototype was designed and manufactured using CAD, CAM and CAE technology. To demonstrate its application and usefulness in the manufacture of complex parts. First, the components that make it up were designed in CAD software: clamps, "worm" screw and casing, to later carry out the finite analysis in CAE software, computer-aided engineering, ending with the simulation and manufacturing in CAM software. This will validate and demonstrate the feasibility of manufacturing the mandrel in steel, with existing resources and with a design that best suits the requirements.

FEM analysis of the stress strain rate during hot forging of steel non-rotational form

The simulation of the clutch lever forging process was carried out using Qform software, which is based on numerical and finite element methods, while the tool itself was modeled in SolidWorks CAD software. The stress-deformation state of the workpiece in the process of hot forging in an asymmetric dies for forging with excess material, which represents one of the most common technologies in modern industrial processes of the metalworking industry was analyzed and monitored in this paper.

INVESTIGATION OF NATURAL FLOCCULANTS FOR USE IN WASTEWATER PURIFICATION PROCESSES

Contaminated industrial wastewater significantly reduces the volume of drinking water. A wide range of composition and insufficient treatment of wastewater from enterprises such as the textile, chemical or metalworking industries, which often fall into water bodies, negatively affect the state of aquatic ecosystems, and that is why it is necessary to carefully select the optimal treatment method. Among the types of wastewater treatment, the coagulation-flocculation process has gained considerable popularity, which occurs due to the adhesive and adsorption properties of coagulants and flocculants, which is widely used in the purification technologies of both natural and industrial wastewater from colloidal particles, radionuclides, phosphates, dyes and suspended particles. Coagulants are able to hydrolyze in water with the formation of various coagulation structures with high adsorption and adhesion properties, flocculants, in turn, contribute to the formation of flakes, sedimentation and filtration, stabilize the cleaning process, improve quality and increase the efficiency of equipment. During the experimental work, the employees of the Department of Chemical Technology and Water Treatment established the advantages of using natural flocculants in the process of wastewater treatment using colored model solutions as an example. A study was made of the influence on the degree of purification of such characteristics as the type of flocculant (for example, chitosan and sodium alginate) and coagulant (Al2(SO4)3·18H2O, ALS, PIX-318), the optimal dose of reagents, the type of dye (direct, active, dispersed) , settling time and content of residual ions. During the research, the Jar-test method was used, the essence of which is to simulate the process of floc formation, which is typical for industrial wastewater treatment plants. The study of the composition of model water samples was carried out using the spectrophotometric analysis method.

Análisis de la formabilidad de láminas de acero AISI 304 con diferentes espesores mediante sus propiedades de tracción

Although AISI 304 steel is widely used and its manufacturers provide resistance data in the quality certificate, these are not sufficient to characterize and predict the behavior of the sheets in the drawing and drawing processes. This is why the objective of this work was to analyze the formability of AISI 304 steel sheets with 16- (thickness 1.5 mm), 18- (1.2 mm), and 20- (0.9 mm) gauges used by the metalworking industry in Colombia by determining intrinsic properties related to the ability of the sheet to withstand stretching and drawing operations such as the strain hardening exponent n, the normal anisotropy rm, and the planar anisotropy Δr. The methodology consisted of analyzing the chemical composition, a metallographic study, and a series of tensile tests. The results show that the steel has a microstructure of twinned austenite grains of size between 15-30 mm. Regarding the mechanical resistance, it was observed that all the mean values of ultimate resistance, elastic limit, and elongation are above the minimum established in the standard. Furthermore, all of the tensile test results changed according to the variation of angles concerning the rolling direction (0°, 45°, and 90°), which indicates the anisotropic character of the sheet. The most relevant result allows us to infer that the 20-gauge sheet has better formability and therefore, better behavior against the stretching and drawing processes.

Against lords and Parientes Mayores. Social conflict and resistance in the late medieval Basque Country

ABSTRACT This work aims to define the structural elements of aristocratic rule, noble lords in Álava and Parientes Mayores (heads of household) in Guipúzcoa and Biscay, over their lordships and church patronages; the fiscal and political opposition presented by hidalgos (petty nobility), peasants, ferrones (metal-industry workers) and townspeople; and the evolution of the resulting conflict over time. We also outline the discourses elaborated to legitimise lordly authority or to reject it, and those mobilised to denounce the arbitrary fiscal demands of the nobility and conditions of political exclusion. In order to illustrate this, we examine the rule of the Rojas and the Hurtado de Mendoza families over the small towns of Antoñana and Santa Cruz de Campezo, and the steadfast opposition to this rule from the towns’ residents.

The impact of three related emission industries on regional atmospheric chlorinated paraffins pollution

Identifying the contributions of various chlorinated paraffins (CPs) sources in the environment plays an important practical role in the prevention and control of the CPs contamination. However, little is known about how main CP-related emission industries affect the regional atmospheric characteristics of CPs, including CP products industry, metal working industry, and polyvinyl chloride (PVC) industry. In this study, 60 passive air samples were collected from five typical cities in Henan Province, China, which had serious CP pollution and different structures of CP-related emission industry. Short chain CPs (SCCPs) and medium chain CPs (MCCPs) were detected in all samples in concentrations ranging of 2.6–7.7 × 102 and 2.1–4.3 × 102 ng m−3, respectively, which were higher than those in most reports. Moreover, Luoyang (LY) is different from other cities, showing a relatively severe MCCP contaminations. The CP pollution characteristics between different cities are obviously affected by the proportion of local CP-related industries. According to the results of cluster heatmaps, the local CP-related emission industrial structure had a greater impact on MCCPs pollution than SCCPs. Additionally, the contribution of metal working industry was beyond that of PVC production industry and CP products industry.

Alloy and process design of forging steels for better environmental performance

In material development processes, the question if a new alloy is more sustainable than the existing one becomes increasingly significant. Existing studies on metals and alloys show that their composition can make a difference regarding the environmental impact. In this case study, a recently developed air hardening forging steel is used to produce a U-bolt as an example component in automotive engineering. The production process is analyzed regarding the environmental performance and compared with the standard quench and tempering steels 42CrMo4 and 33MnCrB5–2. The analysis is based on results from applying the method of Life Cycle Assessment. First, the production process and the alterations on material, product, and process level are defined. The resulting process flows were quantified and attributed with the environmental impacts covering Carbon Footprint, Cumulative Energy Demand, and Material Footprint as they represent best the resource-, energy- and thus carbon-intensive steel industry. The results show that the development of the air hardening forging steel leads to a higher environmental impact compared to the reference alloys when the material level is considered. Otherwise, the new steel allows changes in manufacturing process, which is why an additional assessment on process level was conducted. It is seen that the air hardening forging steel has environmental savings as it enables skipping a heat treatment process. Superior material characteristics enable the application of lightweight design principles, which further increases the potential environmental savings. The present work shows that the question of the environmental impact does not end with analyzing the raw material only. Rather, the entire manufacturing process of a product must be considered. The case study also shows methodological questions regarding the specification of steel for alloying elements, processes in the metalworking industry and the data availability and quality in Life Cycle Assessment.

More than recycling – The potential of the circular economy shown by a case study of the metal working industry

The steel industry is responsible for a quarter of all industrial greenhouse gas emissions. So far, the environmental savings are mainly due to steel recycling. Besides recycling, the circular economy offers strategies to increase material efficiency and thus decrease the primary raw material demand. However, the potentials remain unexploited because circular economy concepts with a higher degree of circularity are not considered. The presented case study of an industrial machining knife illustrates how the production process can be improved by implementing various circular strategies. The environmental performance is analyzed by calculating and comparing the carbon footprint, the cumulative energy demand and the material footprint, and the material efficiency indicator. The results show that the implementation of the three overarching strategies of the circular economy - narrowing, closing, and slowing – contributes to a significant increase in material efficiency. The implementation also has a positive effect on the overall environmental performance. The circular production processes require less energy and resources and cause fewer emissions. Auxiliary processes such as additional transport routes are relevant, as they can reduce or even overcompensate for savings. These processes must be adequately considered and designed.

Ancient mining pollution in early to middle Holocene lake sediments from the Lake Superior region, USA

Determining the timing and transport mechanisms (i.e. fluvial and/or atmospheric) of pollution associated with ancient copper mining on Isle Royale in Lake Superior (United States) is important for understanding the current and future trajectory of ecosystems affected by human activity. This study reports metal concentrations in sediment from two small, closed-basin lakes located on Isle Royale (Lily Lake and Pond 2) as a measure of the extent of heavy metal emissions from Indigenous, precontact mining and annealing activities associated with one of the world’s oldest metal working industries. Lily Lake and Pond 2 are both located near known mines, but neither lake contains mines in its catchment and thus could not have received pollution via fluvial transport. Elevated concentrations of lead in sediments dating to ∼6000 years ago at both lakes provide evidence of atmospheric transport of pollution associated with mining emissions. The age of ∼6000 years before present is consistent with the timing of elevated lead concentrations in sediment from McCargoe Cove on the northern shore of Isle Royale. Collectively, the data indicate that the peak in Archaic Period mining occurred on southwestern Isle Royale ∼6000 years ago and was preceded by periods that varied in intensity and location across the area. The discovery of pollution signals in lake sediments from the Lake Superior region provides clues as to the timing, spatial patterns, and magnitude of one of the world’s earliest large-scale metal mining efforts. These findings provide a basis for determining the transport mechanisms of ancient mining pollution and are a step toward assessing the full environmental impact of mining and metal working efforts by early human civilizations. • Anthropogenic lead was detected in lakes near prehistoric mines on Isle Royale. • The presence of anthropogenic lead indicates airborne pollution transport • The peak of mining and associated pollution occurred ∼6000 years ago. • Findings are consistent with regional sediment records and copper artifact dates.

Improvement of the performance of a multi-blade tool based on selective equipment with cutting ceramics

The increasing pace of industrial production for the production of products and the widespread complexity of the designs of manufactured products, justified by scientific and technological progress, pose a permanent task to the metalworking industry to improve technological processes in order to reduce the time of manufacturing parts and material costs. These requirements lead to the desire of manufacturers to reduce traditional technological processes and significantly increase the processing speed. In such conditions, traditional tool materials are often not applicable, while some materials that were previously not in demand due to the lack of necessary technological conditions are becoming increasingly relevant. One of such materials is cutting ceramics – a material that has the highest efficiency at high cutting speeds, but due to the brittle nature of the fracture provides low stability when used in non-rigid technological systems, under high loads and insufficient attention to the equipment of the tool with ceramic cutting plates. The article is devoted to improving the performance of a multi-blade tool based on selective equipment with ceramic cutting plates during the finishing of the working surfaces of high-precision cast-iron body parts. In the course of this study, the problems of using a multi-blade tool for milling high-precision planes were identified, a way to solve the identified problems was determined, a device was created to determine the microstructural parameters of cutting ceramics based on the known dependence of microstructural characteristics on the electrical resistivity of oxidecarbide cutting plates, a method was developed for selectively equipping a multi-blade cutting tool with oxide-carbide ceramic cutting plates. The effectiveness of the proposed solutions is confirmed by experimental studies.

Clinical Profile of Patients Presenting with Corneal Foreign Bodies: A Cross-Sectional Study Conducted in a Tertiary Hospital in Nepal.

Corneal foreign bodies are one of the commonest forms of ocular trauma, the majority of which occur due to occupational exposure. The aim of this study was to study the profile of patients with corneal foreign bodies. A hospital based prospective study was conducted among 60 patients presenting to the ophthalmology outpatient department in Dhulikhel Hospital-Kathmandu University Hospital (DH-KUH) over a time span of 6 months. Demographic data of patients, clinical characteristics of foreign bodies and associated complications were noted. Most of the patients were males (n=55) belonging to the 21-30 age group (n=24). Majority of them were workers in metal industries (n=26). Welding and cutting metal were implicated as the most common mode of injury (n=53). By virtue of this study, we identified the high risks associated with sustaining this form of ocular trauma. The incidence and hence the prevalence of corneal foreign body can be gradually levelled down if we aware the people about the associated complications and advise them to use protective eye wears (PEW).

Edge crack test methods for AHSS steel grades: A review and comparisons

Due to the economic efficiency of shear cutting, mechanical cutting is used for almost every sheet metal component processed in large numbers. The process parameters recommended both in the literature and in factory regulations generally apply to low- strength, single-phase steel alloys with low ECS. This does not necessarily apply to current types of high-strength alloys, such as those used in body and chassis components for passenger cars or in frame structures of commercial vehicles. As a result, metal working industries and teaching institutes have developed a range of non-standard testing methods to identify the ECS of metals. The ability to prevent edge cracking by the choice of appropriate cutting parameters eliminate the need for costly and time-consuming testing, which in turn reduces machine, tool, material and labor costs. This paper investigates various edge crack testing methods based on current single and multi-phase steel alloys and objectively evaluates them based on multiple criteria. The findings were then linked to the state of knowledge. A particular aspect of this document as compared to a conventional review paper is that the materials used can be regarded as constant across all test methods. This enables an objective comparison and evaluation of the methods used. A simple discussion or comparison of the recorded parameters of the state of knowledge is not expedient due to the large number of metallic alloy systems per material group and the fact that the alloy composition is generally not explicitly documented.

UTILIZING INDUCED MUTAGENESIS IN KAZAKHSTANI WHEAT BREEDING

Mutagenic effect of physical factors and chemical substances (aziridine or ethylene imine, nitrosoethylurea, nitrosoethyleneurea) leads to increase of the spectrum of hereditary variability for breeding purposes, which however is not studied in full extent. Ecological study of anthropogenic factors action leading to disruption of certain links between chemical elements and their combinations, raise of heavy metals concentration in soil, facilitate examination of mutagenic and toxic properties of heavy metals. Increase in wheat yields by improving its genotype is one of the most urgent problems of agriculture and economy. At present, using traditional methods of selection and genetic studies, such as backcross selection, distant hybridization, and experimental mutagenesis, increased efficiency of obtaining genetically modified and improved forms of wheat [1-5]. Heavy metals are defined as metals having a density higher than 5 g/cm3. Of the total 90 naturally occurring elements divided into three classes by the degree of their threat, 53 are considered heavy metals and few are of biological importance. Accumulation of heavy metals such as cadmium (Cd) in the environment is now becoming a major cause of environmental pollution. Toxic metals can inactivate proteins, shifting metal cofactors, blocking active centers or causing allosteric changes. Besides, large number of those possesses ability of inducing mutagenic changes, tumors and causing macroscopic changes. Molecular mechanism of heavy metals toxicity is not completely understood. Cd is non-essential element that negatively affects plant growth and development, released into the environment by power stations, heating systems, metal working industries or urban traffic, which has high cumulative effect with almost no biodegradation. In plants it affects such processes as stomata opening, transpiration and photosynthesis, consequently chlorosis, leaf rolls and stunting are the main symptoms of Cd toxicity in plants accompanied by root browning, leaf red-brownish discoloration. It can also reduce the absorption of nitrate from root to shoot by inhibiting the nitrate reductase activity in shoots. The negative effect of Cd on plant growth was accompanied by an increase in dry to fresh mass ratio in all organs. Several researches have suggested that an oxidative stress could be involved in cadmium toxicity, by either inducing oxygen free radical production, or by decreasing enzymatic and non-enzymatic antioxidants [6-9]. On the other hand, the use of induced mutagenesis showed high efficiency in the production of forms with high yield, quality bakery, lodging resistance, modified plant height and resistance. And, this paper is an attempt of summarizing results performed by our group in this direction.

Wage determination and the bite of collective contracts in Italy and Spain

In several OECD countries employer federations and unions fix skill-specific wage floors for all workers in an industry. One view of those “explicit” contracts argues that the prevailing wage structure reflects the labor market conditions back at the time when those contracts were bargained, with little space for renegotiation. An alternative view stresses that only workers close to the minima are affected by wage floors and that the wage structure reacts to current labor market conditions. We disentangle between those hypotheses by testing whether wages react more to local contemporaneous unemployment or unemployment at the time of contract renewal in Italy and Spain. The results suggest that most wages in the metalworking industry adjusted to the cycle between 2005 and 2013, and that rigidity generated by lack of renegotiation is confined to wages close to the floors (about 12-15% of the total).

Defect initiation and accumulation kinetics in hard-coated WC-Co hardmetal under multi-axial loads at elevated temperature in a novel ball-in-cone test setup

In the metalworking industry, hard-coated WC-Co hardmetal tools are often used in machining applications. Generally, tool life is limited by pre-existing defects in the hardmetal substrate and defects that form during tool application. The complex, multi-axial loading situations and the high temperatures present in the cutting-edge area of machining tools are among the main reasons for the formation and growth of defects in operation. At present, there is a lack in experimental setups that can replicate these conditions. In the current work a novel material testing method is presented, which uses a spherical indenter and inclined specimen surfaces to apply multi-axial loads at 700 °C. The local stress state in the specimen was calculated using finite element simulation implementing an experimentally parameterized material model considering ratchetting and creep of the substrate material. Stresses ranging from mainly compressive to tensile-compressive were predicted. Initiation and accumulation kinetics of defects in the nm- to μm size regime were studied quantitatively. The comparison of stress calculations and damage development shows that positions with tensile-compressive stresses exhibited significantly higher defect formation rates than those with mainly compressive stresses.

Self Reported Hearing Impairments and Associated Risk Factors Among Metal and Woodwork Workers in Gondar Town, North West Ethiopia.

Background:The global prevalence of occupational noise-induced hearing loss ranges between 16% and 24%. The wood and metalwork industries have recently expanded in Ethiopia. This study aims to determine the level of noise exposure and the prevalence of self-reported hearing impairments and associated risk factors among metal and woodworkers in Gondar town Ethiopia.Material and Methods:An institutional-based cross-sectional study was conducted on 580 metal and woodwork workers from February10 to March 25/2020. The data were collected through an interviewer-led questioner and the noise level measurement. Multivariate Poisson regression models were used. P-values less than .05 and adjusted prevalence ratios with 95%CI were used to declare the presence and strength of an association respectively.Result:The mean (SD) average noise exposure level in the wood and metalworking industries was 96.9 ± 3.5 dBA and 96.2 ± 4 dBA, respectively. The overall prevalence of self-reported hearing impairment was 20.7% [95%CI: (17.4-24)]. In an adjusted Poisson regression, listening to music with earphones for more than 2 hours per day (PR = 2.95, 95%CI: 1.32, 6.21) and listening to music at maximum volume (PR = 2.24, 95%CI: 1.05, 4.79) were associated with hearing impairments.Conclusion:The majority of workers are exposed to noise levels that exceed OSHA’s permissible exposure limit value. A hearing conservation program should be implemented to reduce noise exposure levels in the wood and metal work industries. Workers should be aware of the duration and volume of recreational noise exposure.

Influence of applied plasma power on degradation of L-proline in an inductively coupled RF plasma reactor

Surface treatments such as heat treatments, paints, plasma treatments and galvanizing are important in metal working industry. In those treatments, the required adhesion characteristics can be limited if contaminants are present, so there is a need to clean these surfaces. Conventional processes can be costly, some generated waste may be environmentally hazardous and, in some cases, due to part geometry, they are not effective. Alternatively, plasma treatments which are considered to be environmentally clean, more efficient and with lower operating costs can overcome those difficulties. Due to the reactional complexity of these treatments, there are many fields to be researched, such as which reactions are due to impacts of (neutral) chemical species and which are due to excited species and radiation. The present work aims to verify the interactions between Ar-10%O2 plasma using amino acid L-proline in an inductively coupled radiofrequency plasma. This study showed that oxidative plasma promotes high degradation of the sample. A gas analyzer (quadrupole mass spectrometer) coupled to the gas outlet was used and many gaseous products are detected during treatment, such: H2, H2O, CO, NO (Nitric Oxide) and CO2 while L-proline undergoes intense degradation. The conclusions allow to state that the interaction between the Ar/O2 plasma and L-proline promotes intense degradation through the breakdown of the heterocyclic ring of the molecule.

Optimization of the distribution logistics network: a case study of the metalworking industry in Colombia

Logistics management is a key factor for business competitiveness because of the variety of strategies available to improve the distribution of goods through the supply chain, enabling the optimization of the resources assigned to this effect. A key aspect for good logistics management is the distribution network, where the location of the network components plays a key role, especially in the case of distribution centers, which are platforms through which the goods received from factories or suppliers are redistributed to the various points of sale. In the above context, this case study proposes a solution for selecting two locations from among four possible sites for construction of distribution centers for a company in the metalworking industry, aimed at minimizing operating costs through the design of a logistics distribution network, using as a tool the GUSEK software. To this effect, the aspects taken into consideration include vehicle capacity, the costs associated with opening a distribution center, types and volume of the products to be shipped, costs associated with the travel distances, the production capacity of the factories, and customer demand, among others. Execution of the model produces the best locations for the distribution centers and the types of vehicles to be used based on their capacity and the optimal routes for transporting a company’s goods.

Inching toward Modernity: Industrial Standards and the Fate of the Metric System in the United States

That the United States stands almost alone among nations in its failure to adopt the metric system has long been blamed on conservative, reactionary forces. This paper argues against this interpretation, which passes for conventional wisdom in both academic and popular circles. It instead contends that attacks on the metric system in the late nineteenth and twentieth century originated with progressive engineers, entrepreneurs, and industrialists who had taken the lead in setting the nation's first industrial standards. Far from being backward-looking reactionaries, they enjoyed reputations as cutting-edge leaders in the development of the machine-tool industry, the railroads, and the metal-working industries. Many of them pioneered new methods of management that privileged rationality, efficiency, and systemic approaches; indeed, they strongly influenced the development of what became known as scientific management. These individuals deftly advanced their cause through the nation's political institutions, thwarting the metric cause.