Search Results (7)

Cold forging is widely used in many industries. Multi-stage cold forming is usually utilized in forging fasteners. In this study, numerical simulation and experimental investigations were carried out on a five-stage cold-forming process for the manufacturing of low-carbon steel AISI 1010 relief valve regulating nuts. The forming process through five stages included preparation and centering for backward extrusion, backward extrusion over die pin, upset, backward extrusion over a moving punch, and piercing. The formability of the workpiece was studied, such as the effects on forming force response, maximum forming force, effective stress and effective strain distributions, metal flow patterns, and strength. A comparison of the forming forces obtained in the forming experiment with the numerical simulation results of the five-stage cold forming showed a good agreement with the trend of the forming force growth. For the maximum forming force and forming energy, the fourth stage of backward extrusion over the moving punch at the upper face was the largest among the five stages. The total maximum forming forces from the first to the fifth stages were numerically 440.9 kN and experimentally 449.4 kN, meaning the FE simulation and experimental results were in good agreement. The numerically simulated effective strain distributions were consistent with the experimentally tested hardness distributions. Highly compacted grain flow lines also resulted in higher hardness. The overall hardness of the workpiece formed by five-stage cold forming increased by 31% compared to the initial billet. The hardness of the workpiece increased with the forming stages, and the strain-hardening effect was obvious. The strength of the workpiece was significantly increased by five-stage cold forming. Full article

In intelligent manufacturing, the phase content and physical and mechanical properties of construction materials can vary due to different suppliers of blanks manufacturers. Therefore, evaluating the composition and properties for implementing a decision-making approach in material selection using up-to-date software is a topical problem in smart manufacturing. Therefore, the article aims to develop a comprehensive automated material selection approach. The proposed method is based on the comprehensive use of normalization and probability approaches and the linear regression procedure formulated in a matrix form. As a result of the study, analytical dependencies for automated material selection were developed. Based on the hypotheses about the impact of the phase composition on physical and mechanical properties, the proposed approach was proven qualitatively and quantitively for carbon steels from AISI 1010 to AISI 1060. The achieved results allowed evaluating the phase composition and physical properties for an arbitrary material from a particular group by its mechanical properties. Overall, an automated material selection approach based on decision-making criteria is helpful for mechanical engineering, smart manufacturing, and industrial engineering purposes. Full article

Sulfolane in contact with water and oxygen forms acidic (by-) products that are major factors in accelerating the corrosion of carbon/stainless steel. In consequence, water-induced corrosion damage can be a serious problem in industrial systems. Hence, the determination of the corrosion resistance of AISI 1010 steel immersed in sulfolane containing 0 to 6 vol.% water was the principal objective of the study. Evaluation of the corrosion resistance of steel electrodes was performed using a potentiodynamic technique and scanning Kelvin probe microscopy. It was observed that the corrosion products layer that formed on the surface of AISI 1010 steel partially protects it against corrosion in sulfolane with a water concentration in the range from 1 vol.% to 4 vol.%. Interestingly, amounts of water above 4 vol.% cause a break-down of the corrosion products layer and deteriorate the corrosion resistance of AISI 1010 steel as well. Moreover, the relationship between the fractal dimension, corrosion degree of the steel surface and water concentration in sulfolane was investigated. The fractal dimension was determined using 2D grayscale images of AISI 1010 steel registered through a scanning electron microscope. It was noticed that both the fractal dimension and the corrosion degree rose with the increased water concentration in sulfolane. Full article

Sulfolane-induced corrosion can lead to severe impairment in industrial systems. Therefore, determination of solvent corrosivity is valid. Under standard conditions, pure sulfolane is considered to be thermally stable and chemically inert, hence non-aggressive towards carbon/stainless steel. Unfortunately, the sulfolane-evoked corrosion of the industrial installations is observed for sulfolane-based systems polluted by small quantities of oxygen, water and some oxidizing agents. Moreover, sulfolane decomposition with formation of corrosive (by-)products can be escalated by some process parameters, e.g., temperature. The main objective of this study was to determine the corrosion resistance of AISI 1010 steel immersed in sulfolane at temperatures ranging from 25 to 230 °C. Evaluation of the corrosion damage was carried out using electrochemical techniques and scanning probe/electron microscopy, respectively. The general corrosion tendency, corrosion rate and surface corrosion degree were taken into account as well. It was noticed that the corrosion rate linearly increases with the enhancement of sulfolane temperature. Moreover, the interfacial reaction of steel with sulfolane resulted in the formation of corrosion product layer, which is a physical barrier between the corrosive environment and steel improving corrosion resistance of the latter. In fact, the increment of the sulfolane temperature caused a gradual breakdown of the protective layer and the increase in the corrosion degree of the investigated steel. Finally, it was found that the corrosion degree doubles approximately every 42 °C. Full article

An integrated experimental-theoretical approach to the metallurgical characterization of the interfaces in steel plates clad by hot rolling is proposed. Three different couplings of materials have been studied: ASTM A 515 Gr.60 low carbon steel clad with austenitic stainless steel AISI 304L; extra low carbon steel ASTM A283 clad with high Ni content Alloy 59; and, low carbon steel AISI 1010 clad with Cu-Ni Monel 400. Experimental investigations, which are addressed to analyse the microstructural changes near the interfaces and identify the present phases, have been carried out through scanning electron microscopy (SEM) observations, microanalytical measurements by energy dispersive spectroscopy (EDS), and Vickers microhardness tests. In all of the cases examined, the zones that are affected by detrimental microstructural changes results in being considerably less thick than the overall cladding layer. Simulations that are based on theoretical diffusion modelling have been integrated to the experimental characterization by introducing a cladding parameter that acts on the diffusion bonding efficiency, in order to evaluate the effects of process temperature and time variations on diffusion bonding efficiency and stability. In particular, this analytical investigation has shown how the shorter is the duration of the diffusion transient and the higher the temperature, the lower results the sensitivity of the diffusion processes to temperature fluctuations. Full article

This work examines friction properties of smooth-honed thermal spray (TS) low carbon steel coatings produced on an Al-9.0% Si alloy using a plasma transferred wire arc (PTWA) method and an AISI 1010 wire used as feedstock in comparison with the ASM type D grey cast iron (CI) samples subjected to the same (smooth) honing process. CI samples prepared using a standard honing process were also tested for comparison. Reciprocating sliding tests were performed using a Cameron–Plint tribometer against CrN-coated counterfaces within a speed range of 0.06–1.20 m/s covering the boundary and mixed lubrication conditions. Stribeck curves were constructed to show the coefficient of friction (COF) variations with the ratio (λ) of lubricant film thickness to composite surface roughness of TS and CI samples at the mid-stroke position where sliding speeds and surface roughnesses were measured. Examination of the Stribeck curves showed that the TS coated surfaces provided lower COF values compared to CI surfaces given the same smooth honing treatment, e.g., for λ = 2.7 a COF of 0.029 was observed for TS and 0.035 for CI, whereas conventional honing of CI provided a COF of 0.047 under the same condition. Metallographic evidence was given for the surface features and formation of tribolayers on the contact surfaces. The arithmetic mean heights of the surfaces, S_a measured after the tests remained similar for the smooth-honed TS and CI samples. The low COF values of the TS samples were discussed in terms of the surface pores generated during their manufacturing process, and the high oil retention depth ratio (S_vk/S_k) of the TS coated surfaces due to the presence of these pores. Full article

Solvents are widely used in organic synthesis. Sulfolane is a five-membered heterocyclic organosulfur sulfone (R-SO₂-R’, where R/R’ is alkyl, alkenyl, or aryl) and an anthropogenic medium commonly used as industrial extractive solvent in the liquid-liquid and liquid-vapor extraction processes. Under standard conditions sulfolane is not aggressive towards steel, but at higher temperatures and in oxygen, water, or chlorides presence, it can be decomposed into some corrosive (by-)products with generation of SO₂ and subsequent formation of corrosive H₂SO₃. This pilot-case study provides data from laboratory measurements performed in low conductivity sulfolane-based fluids using an industrial multi-electrochemical technique for reliable detection of corrosion processes. In particular, a comprehensive evaluation of the aqueous phase impact on general and localized corrosion of AISI 1010 carbon steel in sulfolane is presented. Assessment of corrosive damage was carried out using an open circuit potential method, potentiodynamic polarization curves, SEM/EDS and scanning Kelvin probe technique. It was found that an increase in the water content (1–3 vol.%) in sulfolane causes a decrease in the corrosion resistance of AISI 1010 carbon steel on both uniform and pitting corrosion due to higher conductance of the sulfolane-based fluids. Full article