Metalworking Industry Research Articles

Heat treatment effect on the carbides in T-15 and M-4 steels

ABSTRACT In the present work, the effect of heat treatment on the microstructure and mechanical properties of T-15 and M-4 high-speed steels was investigated. These steels were produced by powder metallurgy. Due to their frictional wear resistance properties, T-15 and M-4 high-speed steels are widely used in the cutting tool manufacture of the metalworking industry. A heat treatment was applied to both steels, heating them to 1250°C, then air quenching and, finally tempering at 550°C for 2 h, 3 times (triple tempering at 550°C). Steels were characterized by hardness test, metallographic analysis, tensile strength test, and fracture analysis after the heat treatment. Results were compared and related to the metallurgical microstructure, mainly to the distribution of carbides, and also to fracture type and characteristics. Test results and chemical analysis showed important differences between T-15 and M-4 steels.

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Redefining the strain aged state of unalloyed mild steels

Abstract The unalloyed mild steels suitable for deep-drawing have a wide range of applications in the manufacturing industry. They are characterised by a high degree of cold formability, which is greatly reduced by the so-called “strain-aging” phenomenon. This leads to increased scrap formation, which is extremely detrimental to the metalworking industries. Strain-aging of steels is a complex subject with a very rich literature, although most of the research on unalloyed steels dates back to the 1970s and 1980s. Since then, steel making technology has developed intensively, which has also had an impact on the strain-aging process of unalloyed mild steels in practice. Our article describes the nature of the strain-aging phenomenon as it is experienced today. The degree of strain-aging described earlier in the literature is no longer fully present in mild steel products produced with today’s technology.

Trends in occupational respiratory conditions with short latency in the UK.

Occupational short-latency respiratory disease (SLRD; predominantly asthma, rhinitis, hypersensitivity pneumonitis, and occupational infections) prevalence is difficult to determine but certain occupations may be associated with increased susceptibility. This study aimed to examine which occupations and industries are currently at high risk for SLRD and determine their respective suspected causal agents. SLRD cases reported to the SWORD scheme between 1999 and 2019 were analysed to determine directly standardized rate ratios (SRR) by occupation against the average rate for all other occupations combined. 'Bakers and flour confectioners' and 'vehicle spray painters' showed significantly raised SRR for SLRD in general, mostly due to occupational rhinitis (234.4; 95% CI 200.5-274.0) and asthma (63.5; 95% CI 51.5-78.3), respectively. Laboratory technicians also showed significantly raised SRR for occupational rhinitis (18.7; 95% CI 15.1-23.1), primarily caused by laboratory animals and insects. Metal machining setters and setter-operators showed increased SRR for occupational hypersensitivity pneumonitis (42.0; 95% CI 29.3-60.3), largely due to cutting/soluble oils. The occupation mostly affected by infectious disease was welding trades (12.9; 95% CI 5.7-29.3), mainly attributable to microbial pathogenicity. This study identified the occupational groups at increased risk of developing an SLRD based on data recorded over a recent two-decade period in the UK. Occupational asthma and rhinitis were identified as the prevailing conditions and hypersensitivity pneumonitis as a potentially rising respiratory problem in the metalworking industry.

A STUDY TO EVALUATE THE DEMOGRAPHIC PATTERN OF THE INJURY CAUSED BY METALLIC CORNEAL FOREIGN BODY AND ITS OUTCOME AFTER TREATMENT

Objective: This study aims to investigate the demographic characteristics, occupational background, and injury management of patients presenting with ocular trauma involving metallic corneal foreign bodies (FBs). Methods: A cross-sectional study was conducted at the outpatient clinic of Ophthalmology at Pt JLNGMC, Chamba. Data were collected from consecutive patients over three months. Demographic data, including age, gender, and education level, were analyzed alongside occupational background, injury context, and protective measures. Statistical analysis was performed using SPSS version 17.0, with descriptive statistics utilized to present the results. Results: The study revealed a predominance of young males (66%) in the 14-29 age group, with the metalwork industry (47%) being the primary sector where injuries occurred, mainly during metal grinding activities (53%). Lack of protective measures, such as temporary removal of eyewear (39%), contributed to the injuries. Notably, 54% of patients did not attempt self-removal of FBs. Superficial corneal FBs accounted for 45% of cases, indicating significant potential for severe injury. Conclusion: The findings underscore the urgent need for enhanced safety education, rigorous enforcement of protective eyewear usage, and targeted interventions in high-risk occupational sectors to mitigate the prevalence and severity of corneal FB injuries. Addressing these challenges is crucial for preserving vision, reducing healthcare costs, and improving occupational health and safety standards.

ESTUDO EMPÍRICO SOBRE MODELAGEM E OTIMIZAÇÃO DO PROCESSO DEFRESAMENTO DE AÇO DUPLEX: UMA REVISÃO SISTEMÁTICA DE LITERATURA

One of the main production processes used in the metalworking industry is end milling. Thistechnique is used in the manufacture of automotive parts, molds and work tools in general. Duplex steel is a metallic alloy basically composed of 20% to 30% chromium and 5 to 10% nickel, with very low carbon content (less than 0.03%) and with additions of nitrogen, molybdenum, tungsten and copper. Response Surface Methodology (RSM) is astatistical technique used for modeling and analyzing problems in which the response variable is influenced by several factors, the objective of which is to optimize this response. The objective is to present a literature review focused on work that was carried out by modeling and optimizing the steel end milling process using RSM, seeking to identify the evolution of the topic over the years and gaps for improvement. To achieve this objective, the Systematic Literature Review was applied, which is a transparent, scientific and replicable method for carrying outthe literature review.

Effect of Fiber-Laser Parameters on Cutting Accuracy of Thin and Thick S355JR Structural Steel Plates

Fiber lasers, the latest laser-cutting technology, are notable for their high process efficiency, cutting precision, and high cutting quality for thin materials. However, the quality of the cut significantly decreases when machining thicker materials. For now, this is a challenge for the metalworking industry. This study investigated the effects of laser power, cutting speed, and auxiliary gas pressure on the fiber-laser cutting quality of 4 and 6 mm thick S355JR steel plates. To evaluate the influence of cutting parameters on cutting quality, surface roughness, dimensional accuracy and cut taper were measured. A microscopic analysis of the laser cuts was performed, revealing the heat-affected zone, transition zone and unaffected base-material zone. Research results show that laser cutting is a complex process, and the correct choice of cutting parameters greatly influences the cutting performance and final quality. An artificial neural network was created and trained using the results from measuring the quality characteristics to achieve optimum cutting quality. The accuracy of the optimization model was assessed by control samples, which were cut using calculated optimum parameters. The actual values of the quality characteristics only slightly differ from the predicted values, showing that the optimization model is suitable for selecting cutting parameters.

OBTAINING THE NECESSARY MECHANICAL PROPERTIES OF BLANKS OF PARTS MADE OF ALUMINUM ALLOY 7075 BY PHYSICAL MODELING

The article considers physical modeling for aluminum alloy 7075, widely used in mechanical engineering, in particular for elements of aircraft structures. This alloy differs from other rolled aluminum-based alloys not only by high values of strength properties, but also by the presence of a large number of intermetallic compounds of alloying elements. The workpiece for the parts is a round rolled product with regulated mechanical properties. Thus, the purpose of this work was to determine the effect of the deformation pattern that occurs in metal during bar rolling on the mechanical properties of blanks of parts made of aluminum alloy 7075. The present study draws attention to the importance of physical modeling in determining the characteristics of materials necessary for effective management of plastic processing processes. Analyzing the results of physical modeling, we identify the optimal parameters of material processing, such as microstructure, mechanical properties and chemical composition. The results obtained allow a deeper understanding of the physical mechanisms underlying the production of blanks (rods) from aluminum rods of alloy 7075 by rolling, as well as optimizing it to achieve the required technical characteristics of products. Thus, as a result of physical modeling of the rolling process of bars made of aluminum alloy 7075, it was found that when the samples are deformed at a temperature of 250 ° C, the value of the plasticizing stress decreases by about 18%, and a more uniform distribution of microhardness over the transverse and longitudinal sections was obtained compared with deformation at a temperature of 200 °C. The research is of practical importance for the metalworking industry, and can also be used for educational purposes to train specialists in the field of materials science and metalworking. Keywords: workpiece parts, physical modeling, aluminum alloy 7075, metalworking, aluminum alloy microstructure, deformation of samples.

A hospital based study to evaluate etiology and epidemiology of occupational corneal foreign bodies

Occupational injuries to eye are very common. Corneal foreign bodies (CFB) are common occupational eye injury. Studies on corneal foreign bodies due to occupational exposure are ignored in developing countries like India.Our study objective was to determine various occupations related to corneal foreign bodies and demographics, level of education and awareness of patients presenting with CFB acquired during occupational work.A hospital based cross sectional study at a tertiary hospital at Pali, Rajasthan.Patients presenting with CFB were asked about their occupation, level of education, awareness about complications of CFB and use of protective equipments at workplace.We examined total 62 patients with CFBs. All patients were male. 34% were in the age group of 18-29 yrs and 58% were in the age group of 30-45 yrs. Metal work industry was responsible for 29% of presentations and construction work industry for 26% of cases. Only 18% were using protective equipments during occupational activity. 58% patients attempted self-removal of foreign body.CFBs are common among various occupations. The sufferers are commonly young males who are poor and have low education. This occupational hazard can have blinding complications and is generally overlooked. Awareness regarding protective measures must be increased and access to eye care hospital must be increased.

Modelling and optimisation of power consumption and productivity in milling of thin-walled parts

A high percentage of mechanical parts in the metalworking industry (automotive, medical, energetic sector, and etc.), refers to thin-walled structures with optimized shapes and dimension, which produce on high or semi batch production principle. Production processes management, in mentioned industry and production systems, requires the development of appropriate information technologies based automatic systems. Planning and control systems are based on computer-aided technologies. Basis of this system are mathematical-logical models commonly, which is quantitatively link between input process parameters and process performance indicators (output parameters). In this study, modelling of total power consumption and process productivity was performed. Total power consumption and the process productivity were modelled, as very important output indicators in efficient and sustainable production. The modelling is based on the experimental analysis of the machining process during machining of thin-walled parts made of C45E (AISI 1045) carbon steel. Modelling was performed using the least squares method, with the use of ANOVA statistical analysis for the purpose of defining the input factors significance. Depth of cut, milling width and feed per tooth were used as input cutting parameters. Input cutting parameters combined experimental analysed according to Taguchi experimental plan. Based on developed adequate and sufficiently accurate mathematical models, optimization procedure was performed. The goal of optimisation was to minimize the power consumption and maximise productivity.

Compliance with Standard Occupational Health and Safety Measures and Associated Factors Among Small-Scale Metal Industry Workers in Central Ethiopia.

Compliance with workplace health and safety measures can result in considerable reduction in workplace injuries and fatalities and attributed economic costs. However, majority of studies conducted in small-scale industries in numerous countries, including Ethiopia focused on the prevalence of occupational injuries and there is a paucity of evidence on level of employees' adherence to safety measures and the associated factors. Therefore, this study was conducted to assess workers' compliance and factors associated with occupational health and safety practices in small-scale metal industries in Central Ethiopia. This study was conducted in Central Ethiopia. A total of 415 small-scale metal workers were included in this study. Study participants were selected using a simple random sampling technique. A structured interviewer-administered questionnaire was used to collect the data. The collected data were entered using EPI Info version 7.2 and exported to IBM-SPSS Version 22 for further cleaning and analysis. Bivariate and multivariate Binary Logistic Regression were conducted to determine association and during the multivariable regression variables with a p-value <0.05 were considered significantly associated factors. The study found a 39.3% (95% CI: 34.7, 44.1) prevalence of good compliance with safety and health measures among small-scale metal workers. Temporary employed workers were less likely to adhere [AOR=0.43, 95% CI (0.21, 0.93)] and workers who received training were more likely to adhere [AOR=5.75, 95% CI (2.56, 12.9)] to safety precautions. Other significantly associated variables included work experience, working at night, and satisfaction with the current salary. This study sheds light on small-scale metal workers' commitment to workplace safety and health procedures, indicating a compliance rate of 39.3%, which is low. Temporary employees and less experienced workers are less likely to follow health and safety precautions. Workplace health and safety training are associated with increased safety precautions.

DEVELOPMENT OF RECOMMENDATIONS FOR THE IMPLEMENTATION OF COMBINED DEFORMATION TREATMENT “ECAP-DRAWING” INTO PRODUCTION

Combined innovative technology developed in this article makes it possible to produce bimetallic long products in the form of bars and wires with improved mechanical properties, due to the ultrafine grain structure of the material, with less energy and labor costs and implementation of continuity principle in industrial enterprises of metal-working industry. The combination of equal-channel angular pressing with drawing makes it possible not only to harden the composition, but at the same time to preserve important and regulated by a number of GOST plastic properties of the products. This circumstance favorably distinguishes the method under study from other (traditional) types of deformation treatment.

Analysing Metal Melting Methods for Green Transformation of Scrap Metal: Case Study of Latvia using MCDA and SWOT Analysis

Abstract Metal is one of the most widely used materials in the world. It was a crucial driving force in technological development since the industrial age and continues to push us forward to this day. As metal consumption grows, so does the amount of scrap metal generated. Proper utilization of this waste is crucial in mitigating the negative environmental impacts of the metalworking industry. The processing and use of raw materials is often associated with high resource consumption and high emissions. The utilisation of scrap metal instead of raw metal can lead to up to 10 times less electricity consumption and up to 30 times fewer CO2 emissions. However, selecting the most suitable scrap metal processing technology is crucial, particularly in the case of the metal melting furnace which is the backbone of the industry. The efficiency of this process determines the environmental indicators for the entire scrap metal melting process. This paper conducts an analysis of 8 types of metal melting furnaces based on 11 environmental criteria. Furthermore, a SWOT analysis is conducted to evaluate the efficiency of the metal smelting process in Latvian metalworking enterprises and the potential for future expansion.

Application of the process of joining sheet by mechanical cold forming (clinching) using dissimilar materials

In the metalworking industry in general, the need to join components made of sheet metal is very common. The automotive sector, for example, needs to join components made of sheet metal to assemble vehicle bodies. The aeronautical sector needs to join sheets, mainly aluminum, when assembling aircraft. In white goods, there is a need to join low-carbon steel sheets that make up a wide range of household appliances, as well as other sectors such as metal structures, packaging and others. The joining of sheet metal components can be done through some permanent joining process, such as welding and riveting; or by some type of detachable connection, made by screw, nut, stud, pin, among others. A joining technique that has been gaining ground in the industry is plastic deformation joining. Groche et al. (2014) reviewed this technique and present the various existing variations. The most common is known as clinching union. According to Varis (2006), it emerged in the 1980s in an automotive industry in the assembly of chassis. The technique consists of cold joining sheets through the action of a punch that plastically deforms the sheets against a die. The deformation produces an interlook region that joins the sheets, giving the appearance of a spot weld. Sarmento and Pereira (2012) cite the main advantages of this technique: (I) it allows joining a vast amount of materials including metals with non-metals; (II) lower distortions, embrittlement and residual stress; (III) high process repeatability and simple quality control, and (IV) safe working environment.

Force-based inline detection of wear evolution during blanking of cold rolled steels

Blanking plays a crucial role in the metalworking industry as this forming operation defines the final geometric and functional properties of the product. However, the occurrence of wear, as a process-related uncertainty, has a significant impact on the product properties, so it is necessary to determine the occurrence and evolution of wear inline. As current methods are mainly limited to empirical wear monitoring and do not allow differentiation between the type of wear and its location on the tool, a method for monitoring wear based on the blanking force is established. To this end, an optical system is first constructed to observe the evolution of wear during the blanking process and to understand its occurrence. Four main types of wear are found in the processing of cold-rolled steels: adhesion and abrasion on the lateral surfaces, rounding of the cutting edge and chipping at the reversal point. To quantify the wear inline during blanking, features are extracted from the process force and correlated with the occurrence of each type of wear. Since high correlation coefficients are found between process force-based features and the form, size and localization of wear, the proposed method is suitable for inline monitoring of wear evolution in real blanking processes.

Correlating dry wear turning and pin-on-disc tests: a cost-effective approach to machinability evaluation for low carbon steel grades

Machinability tests play a crucial role in the metalworking industry despite their inherent cost and time requirements. This study aims to introduce a novel approach by establishing a correlation between the dry wear turning and pin-on-disc tests, potentially enabling their interchangeability. The industry is particularly interested in this challenge due to the simplified implementation and reduced costs and time compared to the conventional turning test. The correlation between the dry wear turning and pin-on-disc tests was investigated using three low carbon steel grades (12L14, 1212, and 1018) and three medium cutting speeds (150, 180, and 240 m/min). Additionally, a comprehensive cost-energy comparison is conducted to underscore the significance of identifying a laboratory test equivalent to the traditional machinability test. The obtained results reveal a strong correlation between both wear tests. Furthermore, the relative cost analysis demonstrates that the pin-on-disc test costs only 14% of the long-duration turning test, emphasizing its cost-effectiveness.

Work-related diseases and risk factors associated with work-related musculoskeletal disorders among unionized metal industry workers: a cross-sectional study

Objectives. This study aimed to determine the prevalence of work-related diseases (WRDs) and work-related musculoskeletal disorders (WR-MSDs), as well as investigate WR-MSD-associated risk factors, among metal industry workers in Turkey. Methods. The cross-sectional study was conducted with 1374 members of the Birleşik Metal İş Union from 121 companies. Data were collected using a self-administered 30-item questionnaire. Results. The survey response rate was 81.4% (1374/1686). Almost one out of every six workers (14.8%) stated that they had been diagnosed with a WRD, 3.6% reported that they had been diagnosed with an occupational disease and 38.6% of them indicated that they had suffered an occupational accident (OA) at least once. The prevalence of WR-MSDs was 10.7%, of work-related lung diseases was 1.8% and of occupational hearing loss was 0.6%. Quitting smoking, smoking, OA, heavy lifting, time pressure and working in the automotive industry were all associated with WR-MSDs. Conclusions. Interventions aimed at reducing musculoskeletal disorders (MSDs) should focus on smoking cessation, training workers in proper techniques and equipment for lifting and pushing/pulling heavy loads, preventing OAs and injuries, and reducing the time pressure in the workplace in the metal industry.

The self-rating of life quality by workers of metal-processing industry

The cross-sectional study of subjective assessment of quality of life of 300 employees of main professions of metalworking industrial production working in harmful labor environment (classes 3.1-3.4) was carried out using validated Russian version of the WHO QOL-BREF questionnaire. The software Statistica 10 was applied for statistical analysis. The statistical processing of study results was performed by calculating arithmetic mean (M), standard deviation (SD) and presented as M±SD. The non-parametric statistical methods were applied to compare two independent samples: the Mann-Whitney U criterion, the Spearman rank correlation coefficient. The data differences and correlations between the data at p<0.05 were considered statistically significant. Based on the results of analysis, satisfaction of employees with quality of life across all domains was established. The quality of life indicators were independent of gender of respondents. With age and experience, decrease of indicators for all domains was established. High indicators for physical health domain and subjective assessment of health status in examined group can be explained from the standpoint of the "healthy worker effect", but concealment of information about true state of health cannot be ruled out. The metal industry workers working in harmful labor conditions are conditionally healthy and active. There is a need for additional research to obtain objective assessment of their health status.

Surface Integrity Study of AISI 1045 Material in Dry Machining Using Coated Carbide Tool

In metal cutting processes, the source of surface integrity deviation is a combination of several factors. The surface roughness parameter (Ra) is sufficient to determine the quality level of the surface packaging of a product, so it is widely used as a parameter to determine the surface packaging level of a product. Carbide tools dominate modern applications in the metalworking industry and are the preferred choice for metal cutting processes. Carbide tools can be improved through a coating process. In particular, the purpose of this study was to obtain surface roughness and optimum cutting conditions for dry machining of AISI 1045 materials using coated carbide tool when used in dry machining as well as for the development of research and development with research design analysis of the results of student practicum processes in laboratories, especially surface packaging material analysis. The material used is AISI 1045 with PVD TiAlN-TiN coated carbide tool. Combination machining process of cutting conditions, namely cutting speed, feed and depth of cut. Surface roughness test results on AISI 1045 test material with uncoated carbide tool surface roughness value = 9,042µm in cutting conditions: v= 235 m/min; f= 0.05mm/put; a=0.5mm; tc= 5.23 min. And the results of the surface roughness test on the AISI 1045 test material with PVD coated carbide tool with the best average surface roughness value = 6,135µm in cutting conditions: v=235 m/min; f=0.75 mm/put; a=1mm; tc=5.30 min.

Dispersed composition of particulate matter in the air of enterprises workplaces

The research results of the air of the working area of the metalworking, woodworking and construction industry on the presence of solid particles with the usage of gravimetric method and the following optical light microscopy of clarified filters are presented. It has been established that the mass concentrations and the dispersed composition of particulate matter in the air of the industrial plants depend on the type and technological process of the manufactured goods. Maximum mass concentration of the particulate matter has been identified in the workplace air in medium density fiberboards (MDF) milling, while the maximum amount of the particles has been discovered during the casting of metal products and the pressing of products from MDF. The most widespread fraction in the workplace air in bricks and blocks production, pressing and milling of MDF products, casting and metalworking are the particles 1–2.5 µm in size. The difference in the fraction composition of the suspended particles in the different workshops is caused mainly by the quantity of particles with a diameter 0.5–1 µm and 5–10 µm. These studies can be used to develop standards for the maximum permissible concentrations of fine dispersed fractions of particulate matter in the workplace air of enterprises, and to assess working conditions and professional risk in manufacturing processes