Search

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents (2wt.%, 6wt.%, and 12wt.%). Thermodynamic calculation, microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant steel. Results show that the matrix structure in all the three types of steels at room temperature is completely austenite. Carbides NbC and M23C6 precipitate at grain boundaries of austenite matrix. With the increase of Mn content, the number of carbides increases and their distribution becomes more uniform. With the Mn content increases from 1.99% to 12.06%, the ultimate tensile strength, yield strength and elongation increase by 14.6%, 8.0% and 46.3%, respectively. The improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening, including solid solution strengthening, precipitation strengthening, and grain refinement. The increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of Mn. The improvement of the plasticity of austenitic steels can be explained from two aspects: grain refinement and homogenization of precipitated phases. [ABSTRACT FROM AUTHOR]

Using single quality standard deviation, suction resistance standard deviation, total ventilation rate standard deviation, end thread amount, and end content as indicators, an orthogonal experiment was designed with three parameters: wire selection needle roller motor frequency, wire breakage needle roller motor frequency, and wire selection needle roller spacing, to study the effect of parameter changes in pin-roll tobacco structure control equipment on the rolling quality of fine cigarette production. The results showed that the frequency of the wire selection needle roller motor was a key factor affecting the standard deviation of the total ventilation rate and single cigarette weight; the frequency of the wire breakage needle roller motor was a key factor affecting the standard deviation of suction resistance and the amount of wire at the end; the distance between the wire selection needle rollers was a key factor affecting the end content. The optimal parameters for regulating the equipment were the frequency of the wire selection needle roller motor at 33 Hz, the frequency of the wire breakage needle roller motor at 45 Hz, and the spacing between the wire selection needle rollers at 45mm. After regulation, the long cut tobacco rate decreased by 14.39%, while the medium and short cut tobacco rates increased by 26.01% and 20.09%, with little change in the broken tobacco rate. After rolling, there was no significant change in the physical indicators of fine cigarettes, but the standard deviation of single cigarette quality, suction resistance, and total ventilation rate decreased by more than 30%. The end tobacco content and end tobacco content decreased by 61.79% and 36.42%, respectively. The stability of fine cigarette rolling was efficiently improved. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The disposal of oily wastewater is a severe environmental problem faced by the metalworking and automobile industries. When released into the environment, oil-contained wastewater severely threatens plant, animal, and human life. Adsorption has emerged as a unique technique, and using natural adsorbents makes it further cheap and more eco-friendly. Removal of both free and emulsified oil from wastewater by using biosorbents was looked upon as an alternative. The present research aims to develop a novel biosorbent from teak (Tectona grandis) leaves suitable for removing oil from wastewater. Batch Sorption studies were carried out by varying pH, sorbent dosage, contact period, mixing speed, and initial oil concentration. The optimum conditions for maximum adsorption efficiency were determined. The results showed that the adsorption of oil onto teak leaf (Tectona grandis) adsorbent follows Freundlich isotherm with a maximum sorption capacity of 10.115 mg/g and a pseudo-second-order kinetic model. The thermodynamic parameter (ΔH = 5033.75 KJ/mol) suggested oil adsorption's spontaneous and endothermic nature onto the teak leaf (Tectona grandis) adsorbent. The best regeneration efficiency was achieved with 0.01 M HCl. [ABSTRACT FROM AUTHOR]

This article questions the cross-cultural ethnographic insight of metalworking as a male craft, commonly performed in male spaces (workshops) away from female members of society, through the analysis of archaeological evidence for the household-based metal production within multi-gendered and multi-generational households and corresponding but rare ethnographic examples. [ABSTRACT FROM AUTHOR]

At present, powder materials are used in almost all known branches of science and technology such as the automotive industry and metalworking, medicine and nuclear research. This is a wide range of structural and tool materials, and special-purpose materials that have good heat resistance, wear resistance, and resistance within corrosive media. Ultrafine powders are used extensively in development of new functional materials and nanomaterials, since an increase in the discrete nature of structural elements leads to a significant change in material properties. [ABSTRACT FROM AUTHOR]

To improve the nitrogen-expanded crystalline structure, tribological and anti-corrosion properties in industrial field, nitrogen atoms were incorporated into 65Mn steel by plasma nitriding. In this study, 65Mn steel was processed using a plasma nitriding method at 600 °C for the improvement of tribocorrosion resistance. The structural evolutions, chemical elements and chemical bonds of obtained nitrided sample were investigated using a scanning electron microscope, electron dispersive spectroscopy and X-ray photoemission spectroscopy, respectively, and the effects of normal load on the coefficient of friction and wear rate in 0.1 mol/L Ca 3 (PO 4) 2 solution were investigated using a reciprocating ball-on-plate wear tester. The polarization and electrochemical impedance spectroscopy of nitrided sample in Ca 3 (PO 4) 2 solutions were conducted using an electrochemical workstation. The results show that the average coefficients of friction of nitrided samples are decreased from 1.047 to 0.420, and the corresponding wear rates are ranging from 6.274 to 11.250 under the normal loads of 2–10 N. The presence of nitrided layer originated from the plasma nitriding process plays roles of the high hardness and excellent tribocorrosion resistance. The wear mechanism is a combination of abrasive wear and adhesive wear, which is attributed to the formation of hard nitrides. Moreover, the corrosion resistance of nitrided sample is improved by the formation of passive film and the band gap energy of Fe 4 N. • The tribocorrosion and electrochemical properties of plasma nitrided 65Mn steel are improved by LR. • The charge transfer resistance of plasma nitrided 65Mn steel is larger compared with the original 65Mn steel. • The tribocorrosion and corrosion models of nitrided 65Mn steel are revealed by the DFT calculation. • The enhancement of wear and corrosion properties is attributed to the Fe 4 N phases with larger band gap energy. [ABSTRACT FROM AUTHOR]

This study utilizes active control of welding clamping force through periodic additional force (PAF) to assist in fabricating ultrasonic spot-welded copper-aluminum joints. The microstructural characteristics and mechanical properties of the copper-aluminum ultrasonic spot welded with periodic additional force joints were systematically investigated. Periodic additional force was applied to the welding interface, facilitating plastic deformation and flow. This can transform the relatively smooth weld interface into a wave- and swirl-like surface with a maximum peak height of 12 μm. Simultaneously, the mutual diffusion length of copper and aluminum at the weld interface increased from 2 μm to 8 μm. Additionally, the weld interface of ultrasonic spot welded with periodic additional force exhibited typical {111}〈112〉 or {111}〈110〉 shear textures, confirming a strong interface bonding. The effect of the periodic additional force on the thermomechanically affected zone (TMAZ) was also examined. It was discovered that lower periodic additional forces enhanced dislocation density and decreased anisotropy, leading to improved mechanical characteristics. The utilization of periodic additional force in assisting ultrasonic spot welded can significantly enhance the lap shear failure force by up to 59.98%. The paper innovatively proposes a control method of reverse periodic additional force, offering a strategy for the preparation of reliable aluminum-copper joints. [Display omitted] • This paper proposed a novel bottom-up active force control ultrasonic spot welded method based on additional forces. • The active additional force was set periodic, providing control over the joint with minimal alteration of input energy. • The introduction of periodic additional force increased the plastic deformation at the Cu/Al interface. • {110}〈112〉 Brass and {110}〈111〉 P(B ND) textures were generated at low periodic additional forces. [ABSTRACT FROM AUTHOR]

Demand forecasting is essential for improving the operational performance of organizations, as well as for decision making in production planning and scheduling processes. Given this context, this research aimed to apply and compare the results of eight quantitative demand forecast methods, classified as seasonal and non-seasonal, in a case study in a metalworking industry. Thus, the methods were used in the forecast of three cast products, arbitrarily denominated as A, Be C, and the data were obtained from the company that manufactures these products. For this, Excel software was used to perform the applications and to create the time series and the accuracy metrics. As conclusions, the Winters Multiplicative Method obtained the best results for products A and C. On the other hand, for product B, the best result was found with the Winters Additive Method. Therefore, the seasonal models presented the best results for these products. That said, with the performance with the demand forecast methods in this research, it was possible to demonstrate the theoretical-practical application in a case study, to understand the behavior of the products analyzed, and to support the organization in question, with regard to decision making and the formulation of efficient strategies in the area. [ABSTRACT FROM AUTHOR]

Metal foundry represents an important sector within the mechanical industry. The method of casting metal into sand molds has been used for millennia because the freedom it allows the designer in terms of size and shape. The objective of this research is to establish a numerical simulation model, experimentally validated, of molten metal pouring in a sand mold, taking as analysis criteria the internal defects in the body of the bearing support of the 4 500 lb. harrow. In this research, an analysis was carried out, from the Finite Element Method (FEM), of casting process taking into account the molten metal pouring temperature, the mold preheating temperature and the filling speed. These parameters were recorded during the experimental testing of the process. An inspection procedure is shown, in which elements of visual analysis of the piece obtained and of simulation by MEF were used to determine the magnitude and location of internal defects inside the piece. The defects were classified in blowhole, porosity and cold junction, a correspondence was appreciated in terms of their location, between the simulated and the experienced models; while the defects area relative error in these models is less than 10%. [ABSTRACT FROM AUTHOR]

The archaeological visibility of the production and consumption of gold and silver ornaments increased substantially during the Iron Age. A large number of precious metalworks rendered with distinctive 'animal style' motifs have been recovered from elite tombs in north‐west China, and have attracted great interest when investigating the dynamics of exchange, mobility and transcultural encounters in Eurasian antiquity. However, little scientific research has been undertaken to examine the manufacturing techniques and metal composition of such 'animal style' artefacts found in north‐west China and its neighbouring areas in a broader Eurasian context. Using multiple non‐invasive analytical methods, we conducted a detailed scientific analysis of two groups of precious metals excavated from Dongheigou Tomb 12 (fourth–second centuries bce) and Xigou Tomb 1 (third–second centuries bce) in present‐day Balikun county, Xinjiang Uygur Autonomous Region. The results suggest that mould‐pressing technology was employed for the production of the 'animal style' appliqués found in these two tombs. The current analysis provides a definitive explanation for the traces of superficial crafting through their specific microstructure and the tool marks of manufacturing, and will thus be of significant interest for further research concerning the metallurgic knowledge and technological practice of precious metalworking industry in north‐west China and Central Asia. [ABSTRACT FROM AUTHOR]

Haynes-25 is a cobalt-based alloy resistant to oxidation and possesses high-temperature properties. Despite the excellent properties, the machinability of Haynes-25 is extremely difficult. Sustainable machining of this alloy is inevitable for producing earth-friendly products. Thus, researchers and scientists have been seeking alternative sustainable technologies to machine these alloys. In the present study, efforts are made to explore the machinability, energy consumption, and economic feasibility of a novel oils-on-water (OoW) lubrication approach mixed with cryogenic liquid nitrogen (LN). Twenty external turning experiments were performed under this novel cryogenic-LN oils-on-water (LNOoW) approach and compared with conventional machining approaches. Machining performance (temperature, cutting power and energy, tool wear and tool life, and surface quality) and economic aspects (production cost) were considered as response metrics. Column graphs are plotted for each metrics to compare the results. The results showed that the proposed LNOoW lubricooling approach reduced the cutting temperature and improved the surface quality of the workpiece significantly. Furthermore, less cutting power and electrical energy consumption were achieved in the proposed cooling/lubrication approach. The novel LNOoW approach also enabled an extension of about 97.56 to 111.11% of cutting tool life as compared to flood-assisted machining process. In addition, 11.76% of surface roughness and 38.725 ¥ cost reduction was obtained at the lowest level of feed rates. It was noted that better economic benefits could be obtained at the highest feed rate and the mid-range levels of cutting speeds. Furthermore, 50% economic benefits are achieved at medium cutting parameters in the LNOoW approach. Overall, the LNOoW approach out-performed in all the metrics. Therefore, the LNOoW approach has a high potential to replace the old cutting technologies. The present work can be used as fundamental guidelines for the machinist working in the metal processing industry to adopt the hybrid LNOoW approach successfully in the machining process. [ABSTRACT FROM AUTHOR]

Difficult-to-cut material, i.e., AISI D2 tool steel, has been widely adopted in metalworking industries to manufacture dies for piercing, blanking, drawing and thread rolling due to its excellent wear resistance and non-deforming properties. This article attempts an experimental study to determine the effect of cryogenic coolant (liquid nitrogen) on the grindability of AISI D2 tool steel as work material and its results are compared with the conventional dry and wet grinding methods. The effects of the cryogenic coolant on force components (i.e., tangential force, Ft and normal force, Fn), specific grinding energy (u), force ratio, surface roughness parameters (Ra and Rz) and microstructure were observed. The comparison results indicate a significant reduction in grindability indices such as 64% and 44% in Ft, 54% and 34% in Fn, 46% and 30% in Ra and 40% and 34% in Rz, respectively under cryogenic grinding at higher downfeed as followed to dry and wet grinding. The grinding performance in Ft, Fn, u and Ra was also improved with an increased delivery pressure of the liquid nitrogen (LN2). From the results, it is concluded that cryogenic coolant offers an influential method to improve grinding performance and surface integrity of AISI D2 tool steel. [ABSTRACT FROM AUTHOR]

Three halogen-free poly(ionic liquid)s (PILs), composed of polycations (poly(PEGMA-co-METAC), PPM) and different amino acid anions as counterions, were synthesized. The physicochemical properties of three PILs were characterized to confirm their efficacy as viscosity-enhancing additives. The tribological properties of aqueous lubricants containing PILs were investigated by the SRV-IV test. The addition of three PILs to water resulted in remarkable improvements in kinematic viscosity, lubricity, and anti-wear properties. Among them, PPM-Try demonstrated the best tribological performance due to the formation of the more superior protective film on the friction interface through a tribochemical reaction. Furthermore, PPM-Try is non-toxic to environment and demonstrates favorable antibacterial properties, rendering it a promising eco-friendly aqueous lubricant additive for applications in the metalworking and food industry. [Display omitted] • Three halogen-free PILs with amino acids counterions were prepared and employed as water-based lubricant additives. • PILs can significantly enhance the viscosity, corrosion resistance, friction reduction and anti-wear properties of water. • Three types of tribofilms act synergistically to endow PILs with superior tribological properties. • PPM-Try demonstrates favorable antimicrobial activities and low biotoxicity towards earthworm. [ABSTRACT FROM AUTHOR]

The conductive nano-Al/polyaniline composites were prepared by the milling method in the solid state. Here, aluminum nanostructures were prepared in two different mechanical methods, wire drawing and wire milling in the presence of lubricant oil. The effects of the preparation methods on the structures and morphologies of aluminum nanostructures were investigated by XRD and FESEM. The results show that the shape and size of aluminum nanoparticles in the preparation by the wire drawing method are significantly different than the wire milling method. The aluminum nanostructures were prepared by milling method have flake-like nanosheets while the wire drawing method leads to the formation of spherical ultrafine nanoparticles, which particles size are in the range of 30–60 nm. Then, polyaniline was produced using a solid-state polymerization process by the chemical reaction between aniline hydrochloride and potassium peroxydisulfate. Finally, nano-Al/polyaniline composites were prepared by mechanical milling at room temperature. The quantitative analysis was carried out with the materials analysis using diffraction (MAUD) method and weight fraction for aluminum and PANI were calculated 6.66% and 93.34%, respectively. Electrical conductivity measurements show the conductivity (1.2 × 10−2 S cm−1 at 25 °C) for polyaniline emeraldine salt and (1.02 × 10−3 S cm−1 at 25 °C) in nanocomposite respectively. The results show that by adding aluminum nanoparticles to the polymer the conductivity of nanocomposite (Al/PANI-ES) is lower than that for pure (PANI-ES). Thermogravimetry and differential thermal analysis curves show pure (PANI-ES) and nanocomposite (Al/PANI-ES) have a similar thermal degradation process. The total weight loss in TG curve of pure PANI-ES, in the temperature range 45–800 °C is 46.28% but, total weight loss observed in nanocomposite is 38.67%. Therefore, nanocomposite has higher thermal stability than that of the pure PANI-ES. [Display omitted] • Mechanochemical preparation of polyaniline. • Polyaniline/aluminum nanocomposite was prepared in a novel method in the solid state. • A novel method in the preparation of monodisperse aluminum nanoparticles in wire drawing. • In the milling method a flack-like sheets aluminum nanostructures were obtained. • Wire drawing prepared aluminum nanoparticles have less strain than the wire grinding. [ABSTRACT FROM AUTHOR]

Frequent tool failure and rupturing pose significant challenges in friction stir welding (FSW) of thin dissimilar material sheets with diverse thermal and mechanical properties. These issues exacerbate at higher welding speed (ν), demanding greater precision in welding methodology. This paper presents a novel approach to weld 300 μm thin SS304 and 500 μm thick commercially pure aluminum sheets at ν up to 2400 mm/min using H13 tool without wear, obviating the necessity for expensive high-strength tool materials. Furthermore, the use of a pinless tool negates the requirement for an additional pinhole filling step, which is a prevalent challenge associated with pinned tools. The study unveils that higher tool tilt angle (α) reduces flash formation, leading to a higher effective weld thickness, thereby enhancing weld strength. The increased material extraction (2.048 mm3) from the weld center and higher heat generation (7.6%) compared to the pinless tool imposes a speed limit of 300 mm/min for the pinned tool. The thicker layer (4.9 μm) of inter-metallic compounds (IMC) formed at lower ν showed maximum joint strength (70.03% of base Al). The fracture behavior indicates cleavage facet formation becomes more frequent at higher ν , diminishing joint ductility. With a distortion-free, high lap shear strength and enhanced ν , this novel joining method meets the needs of industrial mass production. [Display omitted] • Friction stir welding of dissimilar thin sheets at high speeds (max: 2400 mm/min). • Utilization of a low-cost H13 pinless welding tool, demonstrating zero tool wear. • Use of a pinless tool eliminates the need for an additional pinhole-filling process. • Distortion and defect-free diffusion-based joint with lap shear strength of 70.03%. • Varying IMC layer thicknesses at different speeds determine weld strength. [ABSTRACT FROM AUTHOR]

For sub-sized fatigue specimens made of EUROFER97 in unconstrained contact to ceramic breeder pebbles, exposed to purge gas conditions for different durations in an oven, a chemical surface attack was observed which led to a significant reduction of fatigue lifetime [Aktaa et al., 2020]. To better reproduce the flow of the purge gas in the breeding zone of a Helium-Cooled Pebble Bed Breeding Blanket, the experiment was now repeated by placing the same kind of samples in the helium loop HELOKA HEMAT, where the gas is permanently circulated in a closed circuit, and its water content is controllable. The composition of the gas was monitored with a mass spectrometer and humidity sensors. The samples were exposed to a mixture of helium and 0.1vol% hydrogen at DEMO relevant operating conditions (550 °C, 1.2 bars abs.) for a duration of 8, 16, 32, and 64 days, respectively. New sample holders were designed which allow direct contact of the samples with the gas mixture. A special procedure for the handling of the test section was implemented to avoid contact of the hygroscopic pebbles with air humidity during the preparation phase and during the extraction of the samples from the test rig. The present contribution discusses the various considerations on which the test rig design was based, followed by a description of the experimental setup and preliminary results of the testing campaign. These are similar to the results achieved in the oven experiment. In the future, the loop will be used for tests with up to 200 Pa partial pressure of steam in helium; a mixture that is considered relevant for the DEMO purge gas composition. [ABSTRACT FROM AUTHOR]

The effects of pulsed laser interaction with matter have become a center for research. The pulsed laser has become an indispensable manufacturing tool in the efficient machining of polycrystalline diamond (PCD) and other materials. Herein, the ablation threshold and chemical modification of PCD irradiated using ultraviolet (UV) nanosecond laser is scrutinized. Using a UV nanosecond laser source, a bulk of PCD is ablated in air, and multipulse processing is executed at a wavelength of 355 nm. The ablation threshold of PCD is reported to be ≈3.7326 J cm−2 based on the linear relationship between the laser pulse energy density and the crater diameter, with a Gaussian distribution of the laser intensity on the cross‐section. Furthermore, the sp3 structure transitioned to the sp2 graphite phase when the PCD is exposed to UV nanosecond laser irradiation. Consequently, this study provides a theoretical and experimental reference for UV nanosecond laser micromachining of PCD materials in the research and metal‐working industries. [ABSTRACT FROM AUTHOR]

Inhalation is the main route of exposure to airborne pollutants. To evaluate the safety and assess the risks of occupational hazards different testing approaches are used. 3D airway epithelial tissues allow to mimic exposure conditions in vitro, generates human-relevant toxicology data, allows to elucidate the mode of action of pollutants. Gillian3500 pumps were used to collect the airborne particulate from woodworking and metalworking environments. EpiAirway tissues were used to model half working day (4 h), full working day (8 h), and 3 working day exposures to occupational pollutants. Tissue viability was assessed using an MTT assay. For preliminary assessment, RT-qPCR analyses were performed to analyze the expression of gelsolin, caspase-3, and IL-6. Tissue morphology was assessed by hematoxylin/eosin staining. An effect on the proliferation of lung epithelial cell line A549 was assessed. Acute exposure to workspace pollutants slightly affected tissue viability and did not change the morphology. No inhibiting effect was observed on the proliferation of A549 cells. Preliminary analysis showed that both types of particles suppressed the expression of gelsolin, with the effect of metalworking samples being more pronounced. A slight reduction in caspase-3 expression was observed. Particles from metalworking suppressed IL-6 expression. [ABSTRACT FROM AUTHOR]

We report unexpected classical and quantum dynamics of a wave propagating in a periodic potential in high Brillouin zones. Branched flow appears at wavelengths shorter than the typical length scale of the ordered periodic structure and for energies above the potential barrier. The strongest branches remain stable indefinitely and may create linear dynamical channels, wherein waves are not confined directly by potential walls as electrons in ordinary wires but rather, indirectly and more subtly by dynamical stability. We term these superwires since they are associated with a superlattice. [ABSTRACT FROM AUTHOR]

The Sisak Ironworks Metallurgical Combine arose from the former Caprag Smelter (1938). The technological process of Sisak Ironworks had characteristics of integrated ironworks, including mass production of coke, pig iron, and crude steel, as well as rolled semi-finished and finished products, along with its own significant metalworking industry. The primary, and globally recognized, products of Sisak Ironworks were welded and seamless pipes. Sisak Ironworks was characterized by continuous reconstruction and modernization with the desire to expand the product range and improve the quality system of final products. Sisak Ironworks gained 16th place out of the 200 largest companies in former Yugoslavia according to journal „Ekonomska politika“ in 1986. Sisak Ironworks was the largest metallurgical company in the Republic of Croatia, and the third (after Zenica Ironworks and Associated Slovenian Ironworks), and the only producer of seamless pipes in former Yugoslavia. Sisak Ironworks was of great significance for today’ s Sisak-Moslavina County, because in 1978, for example, more than 90 % of the total revenue came from the ironworks, and at the end of 1989, it employed 13,992 workers and produced around 2.07 million tons of metallurgical products (coke, pig iron, crude steel, pipes etc.). Sisak Ironworks always nurtured solidarity; after World War II, it built more than 3,600 apartments, and approved over 4,000 loans for individual construction of houses, participated in the co-financing of numerous infractructural and communal projects, educational, cultural, sports-recreational, and other activities etc. The City of Sisak is not the same without the Sisak Ironworks, which we are still witnessing today. The development of the Sisak Ironworks improved the social and cultural life of Sisak and contributed to its urbanization. In 1939, at the time of the opening of the Caprag Smelter (the forerunner of Sisak Ironworks), the population of Sisak was 12,920, and in 1971, about 40,000, while in 1991, the city of Sisak had 45,992 inhabitants. There has always been a symbiosis between the metallurgical industry and the city of Sisak. Unfortunately, the Sisak Ironworks disappeared a long time ago due to several reasons (war afflictions, three unsuccessful privatizations, negligence of the relevant state institutions, etc.), so that the metallurgical production of the remains of the original Ironworks in 2019 had reduced to crude steel production (69 kt) to the level between 1955 (46.9 kt) and 1956 (82.5 kt). [ABSTRACT FROM AUTHOR]

Development of more complex hard coatings that can be implemented in increasingly severe and complex conditions is necessary for the evolution of the metalworking industry. Therefore, this research focuses on the synthesis and corrosion study of the [TiCN/TiVCN]n system as a function of the bilayers number. Thus, the structural resulted determined that the quaternary TiVCN coating, which presents very little information so far, presents an FCC structure as the conventional TiCN system, and the inclusion of vanadium atoms that compete with titanium atoms in Wyckoff 4a positions causes a distortion of the crystal lattice that increase with the bilayers number. An increase of 64.3% in the polarization resistance of the multilayers coating with n = 70 bilayers when compared to the n = 1 bilayer. Corrosion rate decreased by 57% when comparing the 70 bilayers coatings with the 1 bilayer coating. The results obtained show that this new multilayer system presents optimum properties to be used as protective coating on engineering devices exposed to high corrosion conditions. •Simulation of (TiCN) Ternary and (TiVCN) Quaternary structures and the multilayer structure. •Analysis of the structural configurations by means of proposed structural models (Hume-Rothery). •Study of the corrosive damage by SEM. [ABSTRACT FROM AUTHOR]

Brass is widely used in the machine industry, automotive, shipbuilding, construction, metalworking industries, as well as in the production of fittings. Certain types of brass, despite the almost identical chemical composition and the same form resulting from the standards, e.g. sheets of a certain thickness, often differ in performance, e.g. mechanical properties. The presented work compares selected mechanical properties of CuZn39Pb2 brass sheets from different manufacturers. [ABSTRACT FROM AUTHOR]

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. • The steel industry misses a great potential offered by the Circular Economy. • Closing like recycling is implemented, but narrowing and slowing is neglected. • Rethinking production chains of steel products offers huge environmental savings. • Circular strategies face the poor material efficiency of metal-cutting processes. • Auxiliary processes can compensate the environmental benefits. [ABSTRACT FROM AUTHOR]

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. • Novel Ball-in-Cone test setup to induce significant multi-axial cyclic loads at high temperatures is introduced. • Experimentally parameterized FE model considering creep and cyclic creep used to determine test setup load situation. • Experimental results show defect initiation and accumulation kinetics in a hard-coated WC-Co substrate. • Numerical results demonstrate stress range and stress ratio dependency of defect initiation kinetics. • Load & damage situation as in milling cutting edges during milling are reproducible in laboratory experiment. [ABSTRACT FROM AUTHOR]

Metalworking fluids (MWFs) are widely used to cool and lubricate metal workpieces during processing to reduce heat and friction. Extending a MWF's service life is of importance from both economical and ecological points of view. Knowledge about the effects of processing conditions on the aging behavior and reliable analytical procedures are required to properly characterize the aging phenomena. While so far no quantitative estimations of ageing effects on MWFs have been described in the literature other than univariate ones based on single parameter measurements, in the present study we present a simple spectroscopy-based set-up for the simultaneous monitoring of three quality parameters of MWF and a mathematical model relating them to the most influential process factors relevant during use. For this purpose, the effects of MWF concentration, pH and nitrite concentration on the droplet size during aging were investigated by means of a response surface modelling approach. Systematically varied model MWF fluids were characterized using simultaneous measurements of absorption coefficients µa and effective scattering coefficients µ's. Droplet size was determined via dynamic light scattering (DLS) measurements. Droplet size showed non-linear dependence on MWF concentration and pH, but the nitrite concentration had no significant effect. pH and MWF concentration showed a strong synergistic effect, which indicates that MWF aging is a rather complex process. The observed effects were similar for the DLS and the µ's values, which shows the comparability of the methodologies. The correlations of the methods were R2c = 0.928 and R2P = 0.927, as calculated by a partial least squares regression (PLS-R) model. Furthermore, using µa, it was possible to generate a predictive PLS-R model for MWF concentration (R2c = 0.890, R2P = 0.924). Simultaneous determination of the pH based on the µ's is possible with good accuracy (R²c = 0.803, R²P = 0.732). With prior knowledge of the MWF concentration using the µa-PLS-R model, the predictive capability of the µ's-PLS-R model for pH was refined (10 wt%: R²c = 0.998, R²p = 0.997). This highlights the relevance of the combined measurement of µa and µ's. Recognizing the synergistic nature of the effects of MWF concentration and pH on the droplet size is an important prerequisite for extending the service life of an MWF in the metalworking industry. The presented method can be applied as an in-process analytical tool that allows one to compensate for ageing effects during use of the MWF by taking appropriate corrective measures, such as pH correction or adjustment of concentration. [ABSTRACT FROM AUTHOR]

The utilization of cutting fluids in metalworking industries causes health issues and environmental impacts. Owing to eco-friendly apprehensions and rising regulations over pollution and contamination, the need for a greener approach is increasing to diminish the employment of cutting fluids and dwindle the ecological impact. Therefore, special attention should be focused on clean and sustainable machining processes. Foremost, the optimal setting for multiple response problems in the manufacturing sectors must be acknowledged to reduce energy consumption. Even though machining industries established mist lubrication with vegetable oil and cryogenics as a substitute for mineral oils-based flooding, its meager lubrication and cooling property at elevated speed lead to a hunt for a new hybrid approach that offers adequate cooling/lubrication (C/L). Moreover, as of now, no information concerning the effects of hybrid cooling on milling of Nimonic-80A is existing. In this holistic investigation, machining of Nimonic-80A under hybrid C/L was compared with other cooling strategies (flood, MQL, and cryogenic) to determine the viability of employing cryogenics and hybrid cooling method. Complex Proportional Assessment (COPRAS) technique was applied to select the optimum cutting conditions to get the ideal surface trait. Besides improving the surface quality, the hybrid condition is treated as a trendsetter which is in legitimate agreement with the latest global swing for sustainable means of production. The optimization result indicated that machining at a cutting speed of 60 m/min and a feed rate of 0.04 mm/rev under the hybrid cooling strategy provides the optimal value, that controls the energy requirement. Pugh matrix method has been deployed to establish the sustainability assessment among the distinct cooling conditions. The research verdict illustrates the suitability of the hybrid cooling strategy and explains the process of going green. [ABSTRACT FROM AUTHOR]