The most important aspect of sustainability in manufacturing is the preservation of energy and natural resources. For modern production, optimized processes that minimize negative impacts on the ...environment are becoming increasingly important. This can be achieved by increasing energy efficiency through low, clean, and renewable energy consumption. There are many ways to produce less pollution, emissions, and waste in machining: by using more environmentally friendly cooling methods; by applying methods that reduce or eliminate the need for utilization of cooling lubrication; improving the energy efficiency of machining operations; determining the optimal cutting conditions that save resources by increasing machining productivity or reducing the metal removal rate (MRR); minimizing power consumption; and reducing carbon dioxide emissions. This article gives an idea of modern manufacturing with a focus on analyzing the current state of machining operations in terms of saving production resources and ensuring more environmentally friendly production using greener cooling methods of machining such as Dry, Conventional cooling systems, Minimum quantity of lubricant (MQL), Minimum quantity of cooling lubrication (MQCL), Nanofluids, Biodegradable Vegetable Oils, Cryogenic Lubrication, and High-Pressure Cooling (HPC). Finally, the important modern trends of providing resource-saving and environmentally efficient technologies in modern sustainable manufacturing are discussed in this paper.
•Present review article deals with the sustainability and resource saving aspects during machining operations.•Different cooling conditions were presented.•Waste minimizing, recycling, pollution etc. were discussed during machining oeprations.
Gas tungsten arc welding (GTAW) technology is widely used in industry and has advantages, including high precision, excellent welding quality, and low equipment cost. However, the inclusion of a ...large number of process parameters hinders its application on a wider scale. Therefore, there is a need to implement the prediction and optimization models that effectively enhance the process performance of the GTAW process in different applications. In this study, a five-factor five-level central composite design (CCD) matrix was used to conduct GTAW experiments. AISI 1020 steel blank was used as a substrate; UTP AF Ledurit 60 and UTP AF Ledurit 68 were used as the materials of two tubular wires. Further, an artificial neural network (ANN) was used to simulate the GTAW process and then combined with a genetic algorithm (GA) to determine welding parameters that can provide an optimal weld. In welding experiments, five different welding current levels, welding speed, distance to the nozzle, angle of movement, and frequency of the wire feed pulses were used. Using GA, optimal welding parameters were determined: welding current = 222 A, welding speed = 25 cm/min, nozzle deflection distance = 8 mm, travel angle = 25°, wire feed pulse frequency = 8 Hz. The determination coefficient (R
2
) and RMSE value of all response parameters are satisfactory, and the
R
2
of all the data remained higher than 0.65.
Hardness is a powerful property to evaluate the deformation behavior of materials. It serves as confident quality control for several processes, especially in the heat treatment of metals. With the ...advent of depth-sensing indentation, this technique embraces the determination of other mechanical properties. As proof, recognized standards are available to guide the evaluation of Young's modulus using instrumented indentation. However, there are continuous efforts to describe the strength using hardness apparatus. This critical review aims to compile all ways of correlation between hardness and uniaxial strength. This relationship is usually addressed by a single value, called constraint factor, vastly recognized in metals as approximately 3. From a theoretical point of view, this value works well for materials with rigid-plastic behavior, where hardening effects can be discharged. Divergent variations presented herein show difficulties in incorporating the effect of plastic properties on the constraint factor determination. In the same way, the empirical determinations did not consider the differences in hardening exponents, putting in the same statistical analysis diverse microstructures. A specific section discusses the constraint factor for nonmetallic materials. There are critical doubts for determining strength from hardness values in this case. The existence of several approaches to estimate the constraint factor in brittle materials did not assure yet a unique value for the same material, which put in evidence the lack of a robust physical basis to understand the plastic deformation under indentation. Future trends are indicated along with these observations to become practical the recent developments that have allied hardness and strength. The most important aspect is to combine adequately the experimental and simulation approaches, which can be supported by an analysis of residual imprints of hardness and finite element model.
Microscale abrasion tests were performed to assess the wear coefficients of six hardfacing materials in the Fe–Cr–C system, having added Ti, Nb, and/or Mo. Hardfacings were manufactured employing a ...new technique, flux-cored double-wire gas tungsten arc welding. Two abrasive materials were used, silica and alumina, to test different degrees of abrasion severity. As a consequence, three regimes of abrasion were observed, one mild and two severe. The mild regime was characterized by wear coefficients lower than 4.1 × 10
−14
m
2
N
−1
. The severe wear regimes could be distinguished by the mean free path measured in the metallic matrix. Two hardfacings performed better under mild regime, one having added Cr, Ti, Nb, and Mo, and the other having high chromium content with added Nb and Mo. The former of these also performed the best under severe abrasion; this material had a balanced carbide content between MC and eutectic carbides that gave rise to the best performance.
Graphical Abstract
Martensitic stainless steel is a potential material class for selection in some tribological systems, particularly those subjected to wear by hard particles and corrosion. To improve its mechanical ...resistance, without loss of corrosion performance, surface treatments such as low-temperature nitriding and carburizing have been systematically employed. In this context, this paper studied martensitic stainless steel samples subjected to different plasma-assisted treatments, in the case the plasma nitriding and plasma carburizing. The treatments were carried out at temperatures of 300, 350 or 400°C, for different times, aiming to compare the scratch resistance of the treated surfaces. Specimens were initially characterized using X-Ray diffractometry, micro and nanohardness measurements. Scratch resistance was performed using the constant load mode for two levels, 8 and 15N. All worn tracks were evaluated using optical interferometry, to get information about the widths and depths of track profiles. Worn surfaces were analysed using scanning electron microscope, revealing tensile cracks on the surface of nitrided samples. The friction coefficient and the wear resistance were analysed and related to the geometry of scratches, which was associated to the micro-mechanism of wear. Despite the high hardness and low friction coefficient achieved using nitriding treatment, the global performance of carburized samples could be considered as more suitable, because the carburized case significantly minimized the cracks formation. Therefore, plasma carburized martensitic stainless steel can be considered an adequate combination for corrosion environments subjected to wear.
•A stainless steel is subject to different treatments of nitriding and carburizing.•High hardness and low friction coefficient were achieved using nitriding treatment.•Carburizing treatment minimizes the formation of tensile cracks.•Carburized stainless steel is a good option for environments subjected to wear.
The objective of this study was to examine the impact of the size of silica sand particles on the wear resistance of two microstructures containing solidification M7C3 carbides in tempered martensite ...matrix (namely, AISI D2 steel and high-chromium white cast iron). Wear tests were conducted using abrasive silica sand particles of three different sizes (0.20, 0.50, and 1.0 mm) in a dry sand rubber wheel tribometer (DSRW) following the ASTM G65 standard. Subsequently, these samples were analyzed using microscopy and three-dimensional optical profilometry. The results showed that the wear loss increased with increased abrasive particle size, particularly when the abrasive size increased from 0.5 to 1.0 mm. The microscopic observation revealed silica sand incrustation and plastic deformation of the tempered martensite matrix, cracking of the solidification M
7
C
3
carbides, and detachment of the carbides and matrix. Furthermore, the largest abrasive particle size triggered a more damaging wear mechanism, leading to severe fracture damage of the solidification carbides.
Manufacturing processes imply different ranges of surface roughness, such as found in dental components. These surfaces have vital roles from a clinical perspective, including essential ...biocompatibility, bacterial adhesion, and prosthetic retention. However, the relationship between the surface topography and these characteristics can be more detailed, especially in texture analysis. For this purpose, three specimens were studied: (i) Ti-6Al-4V alloy manufactured by wire electro-discharge machining (WEDM); (ii) Ti-6Al-4V alloy manufactured by WEDM followed by electropolishing (WEDM + EP); and (iii) a seating platform of dental implant CNC-machined, manufactured in Ti–CP. Surface topography was analyzed through optical interferometry, using the following parameters: Sq (root mean square), Sp (max peak height), Sv (max valley depth), Ssk (skewness), Sku (kurtosis), and Str (texture aspect ratio). The application of the electropolishing process was sufficient to remove all irregularities left by WEDM, rounding the peaks and valleys, meaning a reduction of 69% in Sq value. On the other hand, the deviations in the seating platform’s height distribution can be considered critical for generating a misfit between the implant–abutment pair. In this case, electrochemical machining is recommended for this surface, instead of grinding processes.
Abstract The use of a gouging abrasion test to evaluate the wear of jaw crushers is revised in terms of its procedures, considering the effects of the most significant variables, such as the minimum ...amount of crushed material and the minimum opening between the jaws during the crushing cycle (minimum discharge aperture). A correlation between the work hardening of jaws and the amount of crushed material is presented. The wear of stationary and movable jaws is compared, being the results dependent on the jaw's material and the discharge aperture. The abrasiveness of several rocks was evaluated, showing a good correlation with their Mohs hardness.
It is well-known that diesel engines generate soot during the combustion process, leading to a higher level of pollutant emissions and severe wear of contact surfaces in relative motion, resulting in ...worse engine performance. Carbon black has been used in laboratory wear tests to simulate soot in engine components such as piston rings and cylinder liners. However, there are still many questions to be answered, especially concerning the interaction between the particles, lubricants, and surface topography in contact. In the past years, compacted graphite iron (CGI) has been substituting grey cast irons in engine blocks because of its improved mechanical properties, resulting in thinner walls for lighter blocks and improving engines' performance. However, CGI's tribological behavior of higher strength grades has been scarcely studied due to its production cost and complexity. In the present study, two CGIs of high strength (JV450 and JV500 – ISO 16112/2017) were used as cylinder liners on ring-on-cylinder lubricated wear tests a CETR-UMT-Bruker tribometer. The cylinders' surfaces were honed to a plateau finishing, and the counterbody used was a commercial compression ring of nitrided stainless steel. Carbon black particles were added to commercial SAE CF-30 lubricant, simulating the presence of soot. The testing load and oil temperature were 175 N and 100 °C, respectively, creating a severe wear condition. Roughness measurements using interferometry were performed on the worn surfaces to compare with the plateau's topography and roughness parameters honing texture. The variation of structure height was used as the indicative of liner wear. Results showed almost the same coefficient of friction (COF) for all tested conditions. Still, the reason for each case was different, the ejection of graphite during sliding being more critical for JV450 iron. The carbon black was able to change the contact conditions. The high-strength GJV500 iron performed better, considering a tribological merit index (TMI), less sensitive to the presence of carbon black in the lubricant oil.
•Engine tribology of compacted graphite cast irons.•Carbon black as a surrogate for soot in engine tribology.•Friction behavior of high strength compacted graphite irons.•Piston ring-cylinder liner tribological pair.
Compacted graphite iron (CGI) has been considered an excellent option for heavy-duty engine blocks due to its superior mechanical properties, which allow reduction of weight, enhancing engine ...performance. Abrasion is a recognized wear mechanism in engine blocks, meaning it deserves to be evaluated for CGI. This study analyzed two grades of high-strength CGI (GJV450 and GJV500) submitted to microscale abrasion tests in free ball configuration using two different slurries: diamond and silica. There was more wear to the surfaces tested with silica due to the particle size, which was one order of magnitude larger than the diamond. The data obtained showed that both materials presented similar resistance when tests were performed with the diamond slurry. On the other hand, when silica was used, GJV500 presented 2.5 times greater wear resistance than GJV450, even though its global hardness was only 17% greater.
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