Minimum Entropy Deconvolution (MED) has been recently introduced to the machine condition monitoring field to enhance fault detection in rolling element bearings and gears. MED proved to be an excellent aid to the extraction of these impulses and diagnosing their origin, i.e. the defective component of the bearing. In this paper, MED is revisited and re-introduced with further insights into its application to fault detection and diagnosis in rolling element bearings. The MED parameter selection as well as its combination with pre-whitening is discussed. Two main cases are presented to illustrate the benefits of the MED technique. The first one was taken from a fan bladed test rig. The second case was taken from a wind turbine with an inner race fault. The usage of the MED technique has shown a strong enhancement for both fault detection and diagnosis. The paper contributes to the knowledge of fault detection of rolling element bearings through providing an insight into the usage of MED in rolling element bearings diagnostic. This provides a guide for the user to select optimum parameters for the MED filter and illustrates these on new interesting cases both from a lab environment and an actual case.

Microstructures and mechanical properties of as-cast Al-6.5Mg-1.5Zn-0.5Fe alloys newly alloy-designed for the parts of automobile were investigated in detail. The aluminum (Al) sheets of 4 mm thickness, 30 mm width and 100 mm length were reduced to a thickness of 1mm by multi-pass rolling at ambient temperature and subsequently annealed for 1h at 200~500°C. The as-cast Al sheet was deformed without a formation of so large cracks even at huge rolling reduction of 75%. The recrystallization begun to occur at 250°C, it finished at 350°C. The as-rolled material showed tensile strength of 430 MPa and tensile elongation of 4.7%, however the specimen after annealing at 500°C showed the strength of 305 MPa and the elongation of 32%. The fraction of high angle grain boundaries above 15 degree increased greatly after annealing at high temperatures. These characteristics of the specimens after annealing were discussed in detail.

Wind turbines are nowadays one of the most promising energy sources. Every year, the amount of energy produced from the wind grows steadily. Investors demand turbine manufacturers to produce bigger, more efficient and robust units. These requirements resulted in fast development of condition-monitoring methods. However, significant sizes and varying operational conditions can make diagnostics of the wind turbines very challenging.

The paper shows the case study of a wind turbine that had suffered a serious rolling element bearing (REB) fault. The authors compare several methods for early detection of symptoms of the failure. The paper compares standard methods based on spectral analysis and a number of novel methods based on narrowband envelope analysis, kurtosis and cyclostationarity approach.

The very important problem of proper configuration of the methods is addressed as well. It is well known that every method requires setting of several parameters. In the industrial practice, configuration should be as standard and simple as possible. The paper discusses configuration parameters of investigated methods and their sensitivity to configuration uncertainties

The paper presents the results of the experimental tests of Mg/Al bimetallic bars rolling process in classic and multi-radial modified round-oval-round passes. The bimetallic bar consist of magnesium core, grade AZ31 and aluminium outer layer, grade 1050A. The stocks were round bars with diameter 22.5 mm with an aluminium layer share of 28%. As a result of rolling in four passes, bars of a diameter of about 17 mm were obtained. A bimetallic feedstock was manufactured using an explosive welding method. The use of the designed arrangement of multi-radial modified stretching passes resulted in obtaining Mg/Al bimetallic bars with an uniform distribution of the cladding layer over the bar perimeter and high quality of shear strength between individual layers compared to Mg/Al bars obtained in the classic passes.

The objective of the present study was to investigate the effects of Sn addition on the mechanical and corrosion properties of Mg-1Zn-1Zr-xSn (x = 1, 2, 3, 4, 5 wt.%) alloys prepared by powder-in-tube rolling (PTR) method. The PTR-treated Mg alloys reached 98.3% of theoretical density. The hardness of the alloy increased with Sn addition. Two main intermetallic phases, Mg2Sn and Zn2Zr3, were formed in the alloys. The Mg2Sn intermetallic particles were observed along the grain boundaries, while the Zn2Zr3 particles were distributed in the Mg matrix. The addition of 1 wt. % Sn caused the corrosion potential to shift toward a more positive value, and the resulting alloy exhibited low corrosion current density.

This article presents the results of an experimental study of cold rolling TRB strips of S235JR steel applying one grooved roll and another plain roll. The purpose of the study was to determine the possibility of rolling TRB strips with the technology studied, depending on the dimensions of the charge and the number of rolling passes. In addition, the possibility of reducing the magnitude of TRB strip curvature due to the introduction of asymmetry into the process was investigated. The effect of the rolling process and shape variation on the material’s hardening was evaluated by measuring hardness. Based on the results, it was determined that the greater the initial thickness of the charge, the higher the shape tolerances can be obtained. In addition, hardness variation was observed on the cross-section of TRB strips, which decreased with increasing values of plastic deformation. It has also been shown that it is possible to reduce the curvature of the TRB strip due to the use of double asymmetry.

Modern metal forming processes of non-ferrous metals, particularly aluminum and its alloys, are increasingly based on integrated technologies combining numerous operations in one process line. The subject of this paper focuses on the possibility of using materials after mould casting (simulating a continuous casting process between cylindrical crystallizers – Twin Roll Casting method) for the direct cold rolling process. As a part of this research a pilotage study on metallurgical synthesis and mould casting process of Al-Mg alloys with the magnesium contents of 5%-10%, testing their mechanical, electrical and structural properties as well as susceptibility to cold plastic deformation. This process was carried out with the measurement of strength parameters and confirmed the possibility of cold rolling alloys with a casting structure without prior hot deformation.

Donghua steel continuous casting-rolling (DSCCR) line is a new endless rolling line in which tunnel heating furnace is added before and after roughing mills to change the temperature field of slab and intermediate slab, but this change will affect the microstructure and properties of hot rolled plate. Therefore, the microstructure evolution, mechanical properties, texture analysis, hole expanding and earing test of 2.0 mm thick hot rolled plate produced by DSCCR line at different final rolling temperature of 860°C, 840°C and 820°C are studied. The results show that with the decrease of final rolling temperature, there is an obvious layered microstructure distribution along the thickness direction, and the surface coarse grain area gradually expands inward, at the same time the morphology of cementite also changed from large multi domain lamellar pearlite and long rod cementite to small single domain lamellar pearlite and short rod cementite. The engineering stress-strain curves have discontinuous yield with the yield elongation of 4-5% and the elongations are more than 35%. EBSD analysis shows that small angle grain boundaries and deformed grains increase significantly with the decrease of final rolling temperature, and are mainly distributed in fine grain area. Hole expanding and earing tests show that with the decrease of final rolling temperature, the earing performance decreased but the limiting hole expanding ratio is similar.

In this study, the effect of rolling of 1.25Cr-1Mo-0.5V-0.3C American Iron and Steel Institute 4340 modified steel for highspeed railway brake discs on the microstructure and mechanical properties was investigated. The materials were hot-rolled at 0%, 51%, and 66% reduction ratios, and then analyzed by optical microscopy, scanning electron microscopy, and electron backscattering diffraction (EBSD). needle-shaped ferrite block morphology in bainite varied with the rolling ratio. EBSD analysis reveals dynamic recovery and dynamic recrystallization, affected ferrite block boundaries and dislocation densities during rolling. Mechanical tests showed that hardness, toughness and elongation increase at higher rolling reduction ratio, while strength remained relatively constant. In particular, the impact toughness increased almost twice from the level of 70 J in S1 (0% reduction) to the level of 130 J in S3 (66% reduction). These results showed that the hot rolling can significantly improve the strength and toughness combination of cast brake discs material.

The paper presents research results on the selection of parameters for the asymmetric rolling process of bimetallic plates 10CrMo9-10 + X2CrNiMo17-12-2. They consisted in determining the optimum parameters of the process, which would be ensured to obtain straight bands. Such deformation method introduces in the band the deformations resulting from shear stress, which affect changes in the microstructure. But their effect on the structure is more complicated than in the case of homogeneous materials. It has been shown that the introduction of asymmetric conditions into the rolling process results in greater grain refinement in the so-called hard layer. There was no negative effect on the structural changes in the soft layer observed.

The required rail straightness is achieved by straightening with roller straighteners. The consequence of the straightening operation is the introduction of residual stresses to the straightened rail. An excessive level of residual stresses accumulated in the rail during use in the track may lead to its damage or fracture. ArcelorMittal Poland S.A., in cooperation with Łukasiewicz Research Network – Institute for Ferrous Metallurgy, carried out a research project (POI R.01.02.00-00-0167/16) the aim of which was to reduce residual stresses in railway rails by changing the technological parameters of the straightening process. The results of the presented study relate to rails 60E1 and 60E2. The study includes the measurement, testing, calculations and analyses of the obtained results. The conducted research indicates the possibility of obtaining a low level of residual stress in the rails for a system consisting of a 7-roller vertical straightener and a 9-roller horizontal straightener by changing the roller settings, the shape of the rollers, the shape of the rail foot and its curvature.

In the domain of the equipment and apparatus construction, a permanent preoccupation worldwide is ensuring technical performances and high fiability in exploitation. The users’ requirement growth in this field led to producing materials with high characteristics such as iron-nickel alloys having a high nickel content with special magnetic, thermal, or elastic properties. The theoretical and experimental researches had the aim of obtaining cold rolled strip, thin (2.6 mm) and narrow (86 mm) from iron-nickel alloys with 41% Ni (low content of C: 0.02-0.04%; Fe: 58%; other elements: Mn, Si, Cu, Cr, Al: under 1%). Our own experiments aimed to establish an optimal cold rolling technology of hot rolled strips of iron-nickel alloys, in order to obtain cold rolled strips with superior mechanical and technological characteristics, strip profile according to current standards, including a finished product characterization.

The Randomized Earned Value Method enable to control the time and cost of works during the implementation of a construction project. The method allows to assess the compliance of the current advancement in time and actually incurred costs with the adopted plan. It also allows to predict the date and amount of the project completion costs. Individual assessment indicators (BCWS, BCWP, ACWP) are calculated after the ongoing control of the progression of works. In the case of randomly changing of implementation conditions, the calculated in this way values of the indicators may be unacceptable because of overlarge differences in comparison to actual values. Therefore, it is proposed an EVM enhancement and additional risk conditions analysis. In this approach data from the quantity survey of works are randomized based on analysis of variations between actually measured and planned values of duration and cost of implemented works. It is estimated the randomized values of individual indicators after successive controls of the progress of works. After each project advancement control the duration and cost of the works that remain to be performed are estimated. Moreover, new verified overall time and total cost of the project implementation are also estimated. After the last inspection, randomized values of the final date and total cost of completion of the project are calculated, as well as randomized values of time extension and total cost overrun. Of course, for randomized values, standard deviations of individual quantities are calculated. Therefore, the risk of time and the risk of cost of the project implementation are presented in the risk charts. The proposed approach provides a better assessment of the progress of works under risk conditions. It is worth to add that the method does not require significant changes to the typical construction management process, however, it ensures realistic consideration of the influence of random factors on the course and results of individual works and the entire project.

In the ironmaking, sizes of raw materials such as iron ores and coke must be adjusted for subsequent process in the blast furnace. The depletion of high grade iron ore in recent years necessitates a technology that can utilize low-grade fine iron ores. Thus, steelmakers have been studying the sinter-briquette complex firing process that employs a method of charging the sinter feed together with briquettes made of fine iron ore. In this process, larger briquettes increase the briquette productivity per unit time but decrease the green strength of briquettes and they can break during transportation and charging. Thus, the briquette shape is very important.

Therefore, in this study, we simulate a twin roll briquetting process using the DEM analysis and compared the compressive force distributions in the briquette for different aspect ratios. This study is a new attempt, because research cases by numerical methods on the same or similar systems are very rare. Consequently, the optimal aspect ratio is 0.5 at briquette height 20 mm, 2.0 at 30 mm, and 1.5 at 40 mm. Also, the average compressive force increased in proportion with the pocket height at the same aspect ratio. Therefore, to increase the pocket depth for high productivity, the pocket height must also be increased for obtaining high strength briquettes.

In this study, crystal grain refinement of pure titanium manufactured by electron beam melting through cryogenic rolling was performed. The effect of rolling in a cryogenic atmosphere on average grain size was investigated. Cryogenic atmosphere rolling was confirmed to be smaller than normal temperature rolling. Electron back scatter diffraction (EBSD) confirmed the presence of oriented crystal grains in the material. The deformation, temperature, and stress generated during rolling were calculated using 3D simulation. Finite element analysis (FEM) modeling was used to analyze the trend of average grain size change during the heat treatment of the rolled samples.

At present, most of the existing target detection algorithms use the method of region proposal to search for the target in the image. The most effective regional proposal method usually requires thousands of target prediction areas to achieve high recall rate.This lowers the detection efficiency. Even though recent region proposal network approach have yielded good results by using hundreds of proposals, it still faces the challenge when applied to small objects and precise locations. This is mainly because these approaches use coarse feature. Therefore, we propose a new method for extracting more efficient global features and multi-scale features to provide target detection performance. Given that feature maps under continuous convolution lose the resolution required to detect small objects when obtaining deeper semantic information; hence, we use rolling convolution (RC) to maintain the high resolution of low-level feature maps to explore objects in greater detail, even if there is no structure dedicated to combining the features of multiple convolutional layers. Furthermore, we use a recurrent neural network of multiple gated recurrent units (GRUs) at the top of the convolutional layer to highlight useful global context locations for assisting in the detection of objects. Through experiments in the benchmark data set, our proposed method achieved 78.2% mAP in PASCAL VOC 2007 and 72.3% mAP in PASCAL VOC 2012 dataset. It has been verified through many experiments that this method has reached a more advanced level of detection.

The study proposed the model of “guide mark” defects formation on the internal surface of pipes, produced on PRM mills of PRP – 140. The research of pipe forming at plug rolling mill with stub mandrel has been carried out; regularities of the dimensionless parameters characterizing the deformation of the gap release, depending on the reduction ratio, were determined. The model of “guide mark” defect formation on the internal surface of the pipe has been proposed. This allows for lesser wall thickness variation of rough tubes. It has been shown that, when using dioctahedral pass designs in comparison with hexagonal pass designs the proportion of displaced volume along the pipe axis is greater but the value is lower; thereby, the risk of “guide mark” defect forming is reduced.

Through taking the cold rolling process as the research object, the three-dimensional finite element model of the strip rolling process is established by using ANSYS/LS-DYNA software. The actual rolling product data has strong consistency with the finite element simulation results. The rolling process is dynamically simulated, and the distribution curves of important rolling parameters such as equivalent stress, control efficiency coefficient, transverse rolling pressure, lateral thickness and work roll deflection is obtained. Based on summarizing the influence of rolling parameters on rolling deformation, the research results of this paper can play an important role in the actual rolling process control. The research results have certain guiding significance for the development and optimization of the rolling control system.

A numerical analysis of the process of single-pass rolling of AZ31 magnesium alloy bars in the three-high skew rolling mill has been carried out in the study. Based on the obtained investigation results, the effect of rolling speed on the band twist and the state of stress and strain occurring in the rolled band has been determined. From the obtained results of the numerical studies it has been found that with the increase in rolling speed the unit band twist angle θ, increase, which translates into an increase in the value of tangential stress in the axial zone of the rolled bar. This contributes directly to an increase in redundant strain in the rolled bar axial zone, which brings about a structure refinement. To verify the effect of rolling speed on the flow pattern and the stress and strain state, experimental tests were carried out. It has been found from the tests that the band twist (flow pattern) contributes to obtaining a bimodal structure in the bar cross-section.

Theoretical and experimental research indicates that radial loads have a significant influence on the value of belt-on-idler rolling resistances. Computational models discussed in literature use the notion of unit rolling resistance, i.e. rolling resistance per unit length of the idler. The total value of the rolling resistance of belt on a single idler is determined by integrating unit rolling resistance with respect to the length of the contact zone between the belt and the idler. This procedure requires the knowledge of normal load distribution along the contact zone between the belt and the idler. Loads acting on the idler set have been the object of both theoretical analyses and laboratory tests. Literature mentions several models which describe the distribution of normal loads along the contact zone between the belt and the idler set (Krause & Hettler, 1974; Lodewijks, 1996; Gładysiewicz, 2003; Jennings, 2014). Numerous experimental tests (Gładysiewicz & Kisielewski, 2017; Król, 2017; Król & Zombroń, 2012) demonstrated that the resultant normal loads acting on idlers are approximate to the loads calculated in theoretical models. If the resultant normal load is known, it is possible to assume the distribution of loads acting along the contact zone between the belt and the idler. This paper analyzes various hypothetical load distributions calculated for both the center idler roll and for the side idler roll. It also presents the results of calculations of belt rolling resistances for the analyzed distributions. In addition, it presents the results of calculations with allowance for load distribution along the generating line of the idler.

This article concerns the issues of modeling and the optimizational approach for the performance of ore comminution circuits. A typical, multi-stage comminution circuit was analyzed with the high-pressure grinding rolls unit operating at a fine crushing stage. The final product of the circuit under investigation was, at the same time, a flotation feed in which particle size distribution initially determined the effectiveness of flotation operations. In order to determine the HPGR-based comminution circuit performance, a suitable mathematical model was built wherein the target function was linked directly with the effectiveness of the flotation processes. The target function in the presented model considers the issue in terms of the flotation operation’s effectiveness. The particle size distribution of individual comminution products and resulting from the weight recoveries of individual size fractions were criteria determining the quality of the comminution product. Weight recoveries of individual size fractions, in turn, were tied with the technical operating parameters of individual comminution devices. In the first model, profit maximization was the target function, while the second variant of the model took into account maximization of the useful mineral weight recovery in the concentrate. The HPGR application into ore processing circuits also results in energy saving benefits which were presented in a comparative analysis of the energy consumption of two comminution circuits – the first based on conventional crushing devices, and the second on the HPGR unit application which replaced the rod mills. The main benefit of such a modernization was almost two times lower energy consumption by the fine crushing stage and a decrease in the ball mills’ grinding operations load through bypassing a part of the material directly for the rough flotation operations.

This paper describes comminution processes using the theories of limiting states, elasticity, and plasticity to explain some effects observed in the process of crushing brittle materials. It further describes the phenomena occurring during crushing in high-pressure roll presses and analyzes the effects of selected factors upon crushing results. The evaluation of the usefulness of various hypotheses for interpretation of the crushing process in the high-pressure grinding roll was carried out by means of experimental investigations. A series of laboratory crushing tests were also conducted in which limestone samples were pressed in a hydraulic piston-die press. Comminution conditions in this press are similar to those observed in the working chamber of HPGR presses. The limestone aggregate, placed in a steel cylinder, was exposed to pressure exerted by the stamp of the press. Samples had various particle size distributions, and experiments were conducted for two values of pressing force. Operating pressure was the main parameter influencing the obtained comminution effects, but the particle size distribution also has an impact on the process effects. A comparison of the results of the investigations indicated that there exists a significant potential for adjusting the operational parameters of high-pressure grinding rolls. Internal stresses are a derivate of crushing actions such as compression, impact, bending, and shearing. The result of crushing in a particular crusher depends on the strength properties of particles reacting to a specific type of crushing actions. In every crusher there are many crushing actions out of which one is dominating due to the crusher type. Impact is a dominating factor in impact or hummer crushers. Various actions of crusher elements on the crushed material are beneficiary. For example, the shape of the jaw surface in jaw crushers, cone surface in cone crushers, or roll surface in roll presses are important.