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Electrical steels are widely used in the electrical industry in the construction of many devices, e.g., power transformer cores and distribution transformers. An important parameter of electrical components that determines the efficiency of devices is energy loss during remagnetization. These losses are influenced, among other factors, by steel cutting processes. The common techniques for cutting electrical materials on industrial lines are mechanical cutting and laser cutting. High-pressure abrasive water jet (AWJ) cutting, unlike the technologies mentioned above, can ensure higher quality of the cut edge and limit the negative impact of the cutting process on the magnetic properties of sheet metal. However, the correct control of the process and the conditions of its implementation comprise a complex issue and require extensive scientific research. This work presents a new approach to cutting electric sheets, involving bundle cutting, which significantly increases the processing efficiency and the dimensional and shape accuracy of the cut details. The tests were carried out for bundles composed of a maximum of 30 sheets, ready to be joined in a stator and rotor in a motor. The influence of processing conditions on the quality of the cut edges of sheet metal, the width of the deformation zone, and the burr height were analyzed. The detailed analysis of the quality of the cut edges of electrical bundled sheets creates new possibilities for controlling the AWJ cutting process in order to obtain a product with the desired functional and operational properties. [ABSTRACT FROM AUTHOR]

Problem. Globally, car crashes are the major cause of death, killing 1.2 million people, and despite improvements in car safety, forecasts indicate that car crash deaths will increase significantly by 2030 due to the increase in the number of cars. Such a trend requires an increase in passive safety in the design of cars. It is also necessary to consider with these factors the most popular segments of SUV cars, which during an accident create more dangerous consequences in the event of a side impact, taking into account the mass and dimensions parameters. Goal. The aim is to conduct an analysis of the side collision mechanism of cars of different mass and dimensional parameters. Taking into account the trends in the sale of cars, identifying the most popular classes of cars in Ukraine both on the new car market and on the second-hand market, to further identify problems in testing cars according to various certification protocols. Methodology. The approaches to solving the tasks used in the work are based on the use of statistical data and comparative analysis of various methodologies and certification protocols. Results. Considering that scientific studies of frontal impact are presented by the scientific community in the broadest form, the study of the side impact of two cars is currently a relevant direction, taking into account the global trend towards the production of cars in the SUV segment, which exceed passenger cars in terms of mass and dimensions. In a road accident with a side impact of a passenger car and an off-road vehicle of the SUV segment, we will get a large difference in the height of the primary impact, which is 250 millimeters. That is, all the energy of the impact to the side of the passenger car falls not on the safety bar, but 250 millimeters higher, which will inevitably lead to fatal injuries to the driver and passenger. Unfortunately, the European NCAP and the US National Highway Traffic Safety Administration use moving barriers that are similar in terms of mass and dimensions to an average passenger car. Originality. The obtained results of the analysis of the mechanism of the car side collision make it possible to evaluate the current trend of the automobile market in terms of passive safety and, in particular, to conduct certification tests for side impact in a new way. Practical value. The obtained results can be recommended when studying the structural features of preparing and conducting crash tests.

It is suggested to improve the drawing process in terms of reducing the energy costs for drawing and increasing the process speed and productivity. A general picture of the hydrodynamic modes of lubricant flow in the pressure gaps with their dependences on the main design parameters of the prefabricated drawing tool has been presented. Based on this, the task is to develop the designs of prefabricated drawing tools, where the conditions of hydrodynamic friction and lubricant injection into the deformation zone are guaranteed to be met. The design should be universal, i.e., satisfy the conditions for the exact and specific sizes of draw dies, dies, and the whole drawing unit as well as for the expected dimensions of a finished product and a deviation in the workpiece diameter including the wire and cylindrical workpieces. The task was to develop a simplified method to select a set of draw dies of the pressure section and dies of the working group for the subsequent production of a drawing tool using a hydrodynamic mechanism for capturing and injecting technological lubricant into the deformation zone. [ABSTRACT FROM AUTHOR]

Finishing and hardening by reversible surface plastic deformation of cylindrical parts is considered. Using ANSYS software, a finite-element model is created for the temperature in the deformation zone as a function of the machining parameters. The influence of each parameter is established. The critical temperature beyond which the transient and residual stresses are reduced is determined. [ABSTRACT FROM AUTHOR]

Computer simulation of the processes of three- and four-roll helical rolling of a workpiece from a hard-to-deform alloy using the QForm finite element analysis computing environment was carried out. The rolling processes were simulated with equal pinch reduction and equal pinch diameters of the rolls of a three-roll mill and the main rolls of a four-roll mill. Based on the simulation results, the lengths of the actual deformation zone, the geometric deformation zone, and the external zones for both rolling schemes were compared. It was found that in the volume of the workpiece the accumulated strain is more evenly distributed during four-roll rolling and the spread of the values of the accumulated strain between the center and the surface of the workpiece is smaller. The average value of the effective stress in the cross section of the workpiece in pinch at a steady stage is less in four-roll rolling, and the distribution of effective stress values in the studied section is more uniform. [ABSTRACT FROM AUTHOR]

To determine the force and energy parameters of cold roll-beating of external splines, the characteristics of the deformation zone in cold rollbeating are analysed. The geometric dimensions and position of the deformation zone change with the movement of the roller, the contact arc, and the reduction are very small, and there is an incomplete deformation zone in the initial stage of cold roll-beating. A discrete analytical method for calculating the unit pressure and deformation force is proposed, and the cold roll-beating process is discretized into an infinite number of cold-rolling processes with complex sections. The discrete analytical model of unit pressure and deformation force is established, and the unit pressure value and its distribution characteristics are determined. To verify the discrete analytical model, a finite element model of cold roll-beating is established, and the forming force is calculated. A horizontal milling machine is modified to carry out the cold roll-beating experiment, and the forming force is measured. The predicted results of the discrete analytical model are compared with the simulation and experiment results. The results show that the maximum error of radial force compared with the simulation and experiment results is about 7 % and 4 % respectively, and the variation curve of radial force is basically consistent, but the time of a cold roll-beating process is slightly shorter. The discrete analytical model correctly predicts the magnitude and change process of cold roll-beating forming force. [ABSTRACT FROM AUTHOR]

One of the key challenges related to glaciofluvial aquifers is understanding how the underlying bedrock structures and the associated bedrock surface topography contributed to the deposition of the glaciofluvial sediments and the generation of groundwater flow pathways. In this study from Western Finland, we present a new digital elevation model of the Precambrian crystalline bedrock surface buried up to 100 m beneath the glaciofluvial sediments along the Kurikka depression. We link bedrock topography to structural anisotropy using additional data from rock outcrops, boreholes and gravity data. Brittle deformation zones are seen in the bedrock‐digital elevation model (DEM) as sharp breaks in the rock surface. These vertical fracture zones contributed to the development of interlinked elongate bedrock depressions and delimit rock blocks with different elevations. A narrow, zigzagging trench, with a stepped floor, follows WNW‐ESE and NE‐SW oriented fracture zones and forms a major hydraulic connection between two major parts of the aquifer. Furthermore, the conductive fracture zones are conduits which connect the shallow glacifluvial aquifer system to deep groundwater in the bedrock. Understanding bedrock structures and buried topography is critical for successful groundwater modelling in crystalline, fractured bedrock. [ABSTRACT FROM AUTHOR]

Electrical steels are widely used in the electrical industry in the construction of many devices, e.g., power transformer cores and distribution transformers. An important parameter of electrical components that determines the efficiency of devices is energy loss during remagnetization. These losses are influenced, among other factors, by steel cutting processes. The common techniques for cutting electrical materials on industrial lines are mechanical cutting and laser cutting. High-pressure abrasive water jet (AWJ) cutting, unlike the technologies mentioned above, can ensure higher quality of the cut edge and limit the negative impact of the cutting process on the magnetic properties of sheet metal. However, the correct control of the process and the conditions of its implementation comprise a complex issue and require extensive scientific research. This work presents a new approach to cutting electric sheets, involving bundle cutting, which significantly increases the processing efficiency and the dimensional and shape accuracy of the cut details. The tests were carried out for bundles composed of a maximum of 30 sheets, ready to be joined in a stator and rotor in a motor. The influence of processing conditions on the quality of the cut edges of sheet metal, the width of the deformation zone, and the burr height were analyzed. The detailed analysis of the quality of the cut edges of electrical bundled sheets creates new possibilities for controlling the AWJ cutting process in order to obtain a product with the desired functional and operational properties.

The contact interaction mechanics of deformation broaching in low-plasticity materials is studied. Particular attention is paid to the study of the stress–strain state parameters and the plasticity margin in the deformation zone during the machining of gray cast iron EN-GJL-200. The stress–strain state was analyzed using a finite-element model of the deforming broaching process for each area of the deformation zone. The model parameters of the machined material were determined experimentally by compressing specimens of gray cast iron EN-GJL-200. The changes in the parameters of accumulated strain, stress tensor components, stress triaxiality ratio, hydrostatic stress, and plasticity margin at different deformation zones along the machined specimen depth are analyzed. It is shown that there is a zone of local plastic deformation in conditions of critical contact stresses. This leads to the appearance of tensile stresses that reduce the plasticity margin in the surface layer. The impact of tool geometry on the stress–strain state of the surface layer is also discussed, and recommendations for the optimal working angle of the deforming element are provided based on plasticity margin minimization. [ABSTRACT FROM AUTHOR]

A mathematical module for predicting and analysing the drawing forces is formed and verified. The process used in the current study is drawing. Geometric parameters of the deformation zone and the “selective transfer phenomenon” are also taken into consideration. The experimental verification is conducted through two tests: In the first test, the experimental blanks are cylindrical rods (steel 45, length 150 mm), and are preliminary turned, and the drawplate made of steel 9xc, are used. Regular micro-relief (RMR) hardens the working surfaces of the drawplate. In the second test, the same conditions are applied except for the samples, which represent solid cylindrical billets made of steel 45 with a complicatedly modified surface layer, including a brass film, regular microgeometry and a “servo-witte” copper film. As a result, in the first experiment, the discrepancies are in the range of -29.1% up to +23%. In the second experiment, the discrepancies are in the range of +1.38% up to +48.9%.

To explore the influence of external temperature and loading rate on itsrheological behavior and mechanism, the dynamic impact compression test was conducted on 022 Cr18 Ni14 Mo2 stainless steel by using the split Hopkinson compression bar test platformat at 2 000 s-1～5 000 s-1 and 25℃～400℃.The results show that the flow stress, strain rate sensitivity, strain hardening and temperature sensitivity of the sample are closely related to strain, temperature and strain rate. At a constant temperature, the flow stress, strain hardening effect, and strain rate sensitivity increase with the increase of strain rate.At a constant strain rate, the temperature sensitivity increases with the increase of temperature, and the sample exhibits a significant thermal softening effect. The strain rate sensitivity and strain hardening effect appear to weaken with increasing temperature. In addition, the microstructure observation by scanning electron microscope（SEM） shows that deformation twins are mainly present in the grains, and a deformation zone with positioning or stacking faults is present in the grains. Under high strain rate or low temperature conditions, the number of deformation zone in the grain is more. The deformation twins within the grains help to adjust the degree of deformation between the grains and improve the uniformity of sample deformation at high strain rate.

The operating conditions of piercing-mill shoes of "classical" configuration are discussed. The following main parameters of the shoe configuration affecting the sticking of metal of the hollow shell to the shoes are determined: the length of the cylindrical section of the shoes, its location relative to the axis of the piercing mill, the taper angle of the exit section, the radius of the groove of the shoes, the ovality in the deformation zone. Computer modeling with increasing and decreasing the parameters of the shoes was carried out using QForm 2D/3D software. Of the results obtained, the following parameters of the piercing process that indicate the tendency to the sticking of the metal of the hollow shell to the shoes were selected: the forces acting on the working surface of the shoes during piercing, the time of contact between the shoes and the hollow shell, the contact area, the temperature of the working surface of the shoes during piercing. Procedures for assessing the resistance of the shoes to the sticking of metal of the hollow shell during piercing are proposed. Three alternatives of shoes with reduced tendency to sticking of the metal of the hollow shell are developed by analyzing the modeling results using these procedures. The most promising shoe configuration was determined using computer modeling. [ABSTRACT FROM AUTHOR]

A mathematical module for predicting and analyzing the drawing force is formed and verified. The process used in the current study is drawing. Geometric parameters of the deformation zone and the “selective transfer phenomenon” are also taken into consideration. The experimental verification is conducted through two tests: In the first test, the experimental blanks are cylindrical rods (steel 45, length 150 mm), and are preliminary machined by turning, and the drawplate made of steel 9xc, are used. Regular micro-relief (RMR) hardens the working surfaces of the drawplate. In the second test, the same conditions are applied except for the samples, which represent solid cylindrical billets made of steel 45 with a complicatedly modified surface layer, including a brass film, regular microgeometry, and a “servo-witte” copper film. As a result, in the first experiment, the discrepancies are in the range of -29.1% up to +23%. In the second experiment, the discrepancies are in the range of +1.38% up to +48.9%.

The contact interaction mechanics of deformation broaching in low-plasticity materials is studied. Particular attention is paid to the study of the stress–strain state parameters and the plasticity margin in the deformation zone during the machining of gray cast iron EN-GJL-200. The stress–strain state was analyzed using a finite-element model of the deforming broaching process for each area of the deformation zone. The model parameters of the machined material were determined experimentally by compressing specimens of gray cast iron EN-GJL-200. The changes in the parameters of accumulated strain, stress tensor components, stress triaxiality ratio, hydrostatic stress, and plasticity margin at different deformation zones along the machined specimen depth are analyzed. It is shown that there is a zone of local plastic deformation in conditions of critical contact stresses. This leads to the appearance of tensile stresses that reduce the plasticity margin in the surface layer. The impact of tool geometry on the stress–strain state of the surface layer is also discussed, and recommendations for the optimal working angle of the deforming element are provided based on plasticity margin minimization.

The mathematical model of the stress–strain state during flux-cored wire rolling in round gauges has been developed. Simulation was based on dividing the deformation zone into elementary volumes and simultaneous solution of the plasticity condition for porous materials and power static equilibrium equation inside the elementary volume. A distinctive feature of this model is taking into account the porous medium strain in the deformation zone. The experiments have confirmed the validity of the mathematical model for predicting the powder density and the energy-power characteristics of the process. Based on the developed mathematical model, the criteria and conditions for optimization were formulated, and the algorithm was developed for the automated design of technology for flux-cored wire rolling in round gauges. As an example of the obtained solutions implementation, the calculation of sintered copper flux-cored wire rolling technology was given. [ABSTRACT FROM AUTHOR]

During the renovation of the Gotschna Tunnel from 2019 to 2020, prefabricated elements made of Compex were used for the first time as a deformable yielding zone in the invert zone. The client, construction management, construction company and supplier of the compressible elements worked closely together to implement the design specifications. Consequently, the expectations of the special building material in terms of the production quality of the prefabricated elements and handling on the construction site were more than met. The parties involved in the construction thus see potential for further applications and further developments of Compex. [ABSTRACT FROM AUTHOR]

With continuous pressing by Conform method, the required pressing pressure is created in split container (shoe or die holder) by the contact friction stresses between surface of annular groove of impeller and workpiece fed into it. These stresses, as in rolling, play a positive role and are active. The size of contact area between workpiece and impeller is determined by the shoe length, which also affects the energy-force parameters of continuous pressing process, such as pressing pressure, torque on wheel shaft, and electric driving power. Based on analytical dependences obtained in the study of energy-force conditions, a method has been developed for calculating the minimum shoe length, which is necessary for implementation of a stable metal extrusion process, taking into account metal rheology and parameters of deformation zone. In this case, parameters of complete contact zone and incomplete contact zone between workpiece and surface of the deforming tool are calculated. The use of the obtained engineering solution in analysis of influence of the main design and technological parameters on efficiency of the profile production process by Conform method allows not to use special software systems (such as Deform 3D) but to solve the problem by using publicly available programs (e.g., Microsoft Excel). The results of comparing calculations with experimental data obtained under industrial conditions showed that the deviation was no more than 10%, which confirms reliability of the formulated solutions and the developed mathematical models. [ABSTRACT FROM AUTHOR]

Production practice of hot rolled pipes during development of pressing technology is aimed at on-line determination of power parameters of the process. At present, pressing forces are calculated using semiempirical equations derived for specific equipment and averaged conditions of the process. It should be mentioned that correct calculations of technological parameters of pressing make it possible to optimize this process, as well as to achieve maximum production rate and the required product quality. Estimated pressing force allows to forecast capability of production of a given molded item, serves subsequently as one of the main technological parameters for optimization of existing technology. This work is devoted to the analysis of deformation zone geometry as one of the main constituents of analytical dependences for determination of pressing force. Boundary friction conditions in the deformation zone have been considered. Four dependences for determination of pressing force have been considered, which demonstrated good agreement between calculated and actual values. [ABSTRACT FROM AUTHOR]

The quality and accuracy of pipes produced by modern pipe-rolling plants are mainly dependent on the quality of the shells produced by piercing mills. Therefore, in designing rolling tool, followed by setting up a piercing mill, it is necessary to ensure that shells produced are of high accuracy and quality. To this end, the effect of changes in the parameters of the deformation zone and the boundary conditions on the piercing process should be taken into account. The deformation zone of a piercing mill and its main sections are considered. The effect of change in each parameter on the dimensions of the resulting shell and on the controlled parameters of the piercing process is determined. The accuracy of shells depends on the capability of the roll design to ensure that the angle of the sizing portion of the plug corresponds to the angle of the exit cone of the roll, taking into account the distortion of its profile due to the turn through the feed and toe angles, and the quality depends on the capability to ensure the operation in the recommended ranges of controlled parameters of the piercing process. For hard-to-deform high-alloy steels, narrower ranges of controlled parameters are used. The effect of the type and design of the rolls of the piercing mill on the parameters of the deformation zone and the dimensions of the resulting shell is studied. [ABSTRACT FROM AUTHOR]

Based on the analysis of the essence of localization of the deformation zone the display signs of this factor and the accompanying positive effect were established. It was the basis for combining a wide range of plastically shaped car parts into groups with the subsequent development of standard (basic) technological processes for each of them.The first group includes hollow cylindrical parts with a flange. The basis of the second group of parts are stepped shafts and axles with slots. The third group of parts are elastic elements of the car suspension, consisting of strips of variable thickness along the length. Representatives of the fourth group are cylindrical solid and hollow parts with a perpendicular end. This approach allows us to form the concept of building advanced industrial technologies.

In the present work, studies have been carried out on the variations in the microstructure and hardness of P91 base-metal and welded joint. This variations result from the grit blasting and thermal cycle experienced during the thermal spraying process. The microstructural effects have been analyzed in terms of the depth of the deformation zone. Scanning Electron Microscopy and Xray diffraction were used as characterization techniques. The grit blasting carried out prior to thermal spraying has resulted in the highest change in sub-surface hardness of the heat affected zone (HAZ). However, flame treatment further reduced the subsurface hardness of the heat affected zone. The depth of deformation zone was highest for inter-critical heat affected zone (IC-HAZ). The overall coating process resulted in an increase in subsurface hardness of various regions of HAZ and fusion zone (FZ). The base metal showed a 7% increase in subsurface hardness due to the overall coating process. The IC-HAZ showed maximum variation with 36% increase in subsurface hardness. The coarse grained heat affected zone (CG-HAZ) and FZ did not show any change in subsurface hardness. As a whole, the hardness and microstructure of the welded joint was observed to be more sensitive to the thermal spray coating process as compared to the base metal.

A comprehensive study of the features of physical and mechanical processes occurring in the deformation zone of metal during continuous extrusion is carried out with rectangular Cu-ETP buses 10 × 60 mm in size. With the use of finite element computer simulation, values of the power parameters of the extrusion process are obtained. It is noted that the values of the torque and force increase until the free space of the press chamber is filled with metal, reaching maxima of 12.26 kN m and 1.54 MN, respectively. As a result of an analysis of the stress-strain state of metal in the deformation zone, the fields of distribution of equivalent strain, strain rate intensity, and average stresses are obtained and the graph of change in the metal temperature with the time of the extrusion process is plotted. The maximum of the equivalent strain and compressive stresses are observed in the region of contact between the workpiece and the abutment of the press container. That is also where the most intense deformation-induced heating of the metal occurs. A comparison of the results of modeling and microstructural studies indicates that a significant part of work on refining the cast structure takes place at the entrance to the deformation zone and in the abutment region, where the level of compressive stresses is the highest. Plastic deformation of the metal passing through the die leads to the formation of an oriented crystal structure with a grain size of 25 to 30 µm. The results of measuring the hardness of the samples are very consistent with the results of analyzing the structure in the studied regions of the deformation zone. When the workpiece passes through the abutment region of the press container, deformation-induced heating occurs, which leads to a decrease in the hardness from 93 to 67 HV. After the metal passes through the die, recrystallization processes continue in it, leading to a slight increase in grain size and, accordingly, a decrease in the hardness from 79 to 74 HV, which lasts until the bus comes into contact with a cooling medium. [ABSTRACT FROM AUTHOR]

The narrow Morris Jesup Spur and an adjacent broader western rise extend 220 km into the Eurasia Basin from the shelf edge north of Greenland. We have used a hovercraft platform drifting with the sea ice to collect the first seismic reflection transect across an area postulated to be a former triple junction between the Greenland, Eurasian and North American plates. The narrow, flat-topped Morris Jesup Spur is a succession of west-dipping (-3°) sediments overlying a basal volcanic unit truncated at the top by an unconformity. The Morris Jesup Rise is formed by intensely deformed sediments and volcanic rocks with a deformation front to the northwest. The basin between the Morris Jesup Rise and the Lomonosov Ridge has a sediment thickness of >3 km with a large submarine channel/levee complex in the upper part and repeated volcanic units present in the deeper stratigraphy below 1.0 sec. sub-bottom. Volcanism on the Morris Jesup Spur is considered to be Late Cretaceous-early Cenozoic in age, and continued into the late Miocene on the Morris Jesup Rise and possibly into early Oligocene in the SW Amundsen Basin. The western slope of the Morris Jesup Spur represented the continental slope north of Svalbard in the Late Cretaceous. A block which included the Morris Jesup Spur and Yermak Plateau rifted off during the initial opening of the Eurasia Basin and moved as part of Greenland until about Chron 22. The architecture of the Morris Jesup Rise is a result of plate convergence possibly including a former extensional plate boundary segment which connected the Gakkel spreading centre to the Hornsund Fault between Chron 22 and Chron 13. The Morris Jesup Rise may be a northern tectonic outlier of a more extensive Eurekan tectonic domain hidden below the Lincoln Sea continental shelf. The Morris Jesup Spur remained subaerial until latest Miocene and submergence of the spur most likely intensified the East Greenland Current. [ABSTRACT FROM AUTHOR]

A mathematical module for predicting and analyzing the drawing force is formed and verified. The process used in the current study is drawing. Geometric parameters of the deformation zone and the "selective transfer phenomenon" are also taken into consideration. The experimental verification is conducted through two tests: In the first test, the experimental blanks are cylindrical rods (steel 45, length 150 mm), and are preliminary machined by turning, and the drawplate made of steel 9xc, are used. Regular micro-relief (RMR) hardens the working surfaces of the drawplate. In the second test, the same conditions are applied except for the samples, which represent solid cylindrical billets made of steel 45 with a complicatedly modified surface layer, including a brass film, regular microgeometry, and a "servo-witte" copper film. As a result, in the first experiment, the discrepancies are in the range of -29.1% up to +23%. In the second experiment, the discrepancies are in the range of +1.38% up to +48.9%. [ABSTRACT FROM AUTHOR]

The piercing of billets in a helical rolling mill with guide disks is considered. The resulting sleeve sizes are shown to differ significantly from the sizes of the sleeves produced using other piercing schemes because of severe tangential deformation. As a result, the energy–force parameters of piercing are different and the results of their calculations according to the generally accepted empirical dependences are inadequate. The results of piercing simulation with the QFORM 3D software package are presented. [ABSTRACT FROM AUTHOR]

Nine total magnetic profiles in the S–N direction of the Central Indian Ocean (CIO) have been interpreted with spectral and Werner deconvolution techniques to obtain approximate depths to shallow (magnetic basement) and deeper (Curie isotherm) interfaces of the oceanic crust. From these preliminary depths, tentative crustal models for all these nine profiles are prepared. These tentative models of the area show varying thickness of the oceanic crust, supporting the deformation history. It is inferred from these tentative models that deformation extends beyond the zone identified south of 8°S latitude. There is good agreement between the spectral and Werner deconvolution depths. [ABSTRACT FROM AUTHOR]

A dynamic model of the cold rolling process at the continuous rolling mill that combines the model of the electromechanical system and the model of the deformation zone has been developed. The paper presents the results of the study of kinematic parameters, force and energy parameters of the deformation zone with regard to the fluctuating nature of the process variables and to the dynamic processes running in the electromechanical system. It is shown that the variations in the stated parameters are of fluctuating unsteady nature, which has an adverse effect on operation of equipment and quality of finished products.

Tubular parts with an external finned heat-exchanging surface are usually produced by the laborious method of cutting on lathes. Besides, there is a method for the high-performance manufacturing of fins by cold knurling with ring-cut knurls, which, compared with cutting, reduces labor intensity by two to six times with a significant increase in the operational properties of the product. The disadvantage of the cold knurling method with ring-cut knurls can be unwanted surface defects and deformations of the entire product. Obtaining finned surfaces on ring blanks with high surface quality during knurling requires accurate calculation of the ratio of longitudinal and transverse strains. The most important factors determining the ratio of longitudinal and transverse strains (rolling-out and rolling-off) are the length and width of the contact surface. The need for a quantitative assessment of the parameters of longitudinal and transverse strains determined the purpose of this manuscript. This study aimed to develop a methodology for calculating the contact surface of a knurl with a ring blank (pipe) when knurling with ring-cut knurls. The proposed method for calculating the knurl's contact surface with a tube when knurling with ring-cut knurls allows for estimating the recommended range of pipe sizes for knurling. Based on the dependencies mentioned in the manuscript, the limiting sizes for blank pipes were calculated to ensure high-quality finning. Experiments on cold rolling of ribbing on pipes with different lengths and diameter ratios were carried out, confirming the possibility of using the proposed methodology for calculating the knurl's contact surface with a pipe when knurling heat-exchanging finning with ring-cut knurls. [ABSTRACT FROM AUTHOR]

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In this paper, the roller (three-roll) molding of a plate stock, based on elastoplastic bending, is investigated. Physical models of the deformation zone during the interaction of the workpiece with rolls are presented considering two stages: when the upper roll is moved without rotating the rolls and when all three rolls are rotated without moving the upper roll. The results of an experimental study of the deformation zone parameters are obtained, and they are used to determine the profile of the tubular billet during molding on a specialized bending machine, for the two stages of the bending process. The experiments showed that for the first bending stage, the billet in the zone of separation from the upper roll has a complex curvature and symmetrical three-point and four-point contacts with the rolls. The second stage of bending with the rotation of the rolls is characterized by an asymmetric deformation zone during three-point contact. Finally, the regression equations for the geometric parameters of the bent workpiece profile sections are obtained. [ABSTRACT FROM AUTHOR]

Spreading stress--strain zone at bending or profiling of laminar composite is in function: layer material characteristic, geometric layer size, parameters at deformation layered composites and deformation degree. The mechanical properties of the layered material significantly affect the position and intensity of the voltage--deformation zone and the way of making the laminar composite. If the mechanical properties of the layers are significantly different, the stress zone deformation defines the material of the layer with higher mechanical properties. This paper deals with the case when the mechanical properties of the layers are very similar. Stress of the states can be simulated with program packages that are related to areas, ie possible of the stress--strain states area. One of these software is ANZIS. In this program, simulation of the position of the two--layer laminar composite with Cu--Al layers was performed. The simulation was performed by force bending in the middle of the work pieces [ABSTRACT FROM AUTHOR]

This study investigates the climatology of the wet and dry conditions in the pre‐summer monsoon season of the Philippines that are less emphasized in previous works. Wet cases (Type W), which account for about 23% of the total pre‐summer monsoon days from 1979 to 2015, are identified from April 1 to the monsoon onset defined by the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA). The differences between the Type W and dry cases (Type D) are presented. The synoptic conditions associated with the Type W and Type D cases are sub‐divided into two sub‐types based on the wind conditions, the (a) westerly winds at 925 hPa (WINDS925hPa) intrusion over Luzon Island (120°–122.5°E, 12.5°–22°N) (Type WW and Type DW), and (b) enhanced easterly WINDS925hPa (Type WE and Type DE). The Type WE (Type WW) cases account for about 63.9% (36.1%) of the total Type W cases, while the Type DE (Type DW) cases account for about 88.1% (11.9%) of the total Type D cases. A subset of Type WE cases (Type WEDef), which features an eastward propagating cold front to the north of Luzon Island and an intensifying anticyclone to its west originating from the east of the Tibetan Plateau and their differences are also examined. These two opposing circulations interact with the subtropical high over the northern Pacific and the easterlies over Luzon Island, and form a deformation zone. The confluence region of this deformation zone, where the cold front interacts with the warm and humid air brought by the easterly WINDS925hPa, lies over Luzon Island and contributes to the convective activities during the pre‐summer monsoon over this region. This is the first attempt to clarify and document the role of deformation zones as another synoptic‐scale convective system during the pre‐summer monsoon season of the country. [ABSTRACT FROM AUTHOR]

Theoretical and experimental research of the power-force parameters of the deformation zone during rolling, drawing and pressing is carried out. The general laws and characteristic features of the movement of deformable layers of material in the deformation zone for each of these methods of working of materials by pressure are shown. The classification of these processes, as well as the combined rolling-drawing and rolling-pressing processes, is given depending on the position of the neutral section in the deformation zone and the direction of the line of action of the stock pressure force acting on the tool relative to its axis of rotation. [ABSTRACT FROM AUTHOR]

A refined mathematical model is developed for the prediction and analysis of the drawing force applied to nonhollow cylindrical blanks with a modified surface layer in machining by a tool with regular surface microrelief when innovative metal-cladding lubricants are employed and frictional wear is eliminated by the Garkunov–Kragel'skii effect. [ABSTRACT FROM AUTHOR]

The upper cell layers of machined solid wood surfaces will usually be damaged and compacted due to cutting forces. The deformation zone may be instable due to temperature and moisture variations as a consequence of artificial surface treatment or environmental interaction. Therefore, an evaluation method of surface stability in this respect would be desirable. In the frame of the new developed surface roughness evaluation method an individual wetting procedure has been developed, whilst surfaces have been characterized by 3D roughness measurement. The stability of surfaces is characterized by appropriate roughness ratios measured before and after wetting. The core depth Sk of the Abbott parameters is the most sensitive indicator to any changes in the deformation zone. Different machining processes may produce surfaces with different stability but wood species have also definite influence on the surface stability, probably due to their density and moisture conduction properties. Latter is supported by the fact that the half-time of moisture evaporation from surfaces may differ considerably. In these experiments, planed and precision-planed surfaces were compared. According to the working principle of the precision planers the planing tool is held stationary whilst the work piece does the feeding motion, thus the blade produces a very thin slice. Using this machine, the machining roughness can be reduced to minimum as it is possible to avoid formation of cycloid arcs (like in case of traditional planing) and also possible to avoid dust formation (like in case of sanding). Investigations were conducted on Norway spruce (Picea abies), larch (Larix decidua), scots pine (Pinus sylvestris), sessile oak (Quercus petraea), black locust (Robinia pseudoacacia), aspen (Populus tremula) and beech (Fagus sylvatica). Black locust and the sessile oak have had most stable surfaces by both machining methods. The deformation zone of precision planed surfaces has been proven to be more stable than the one of planed surfaces for all wood species.

Although asymmetric rolling is employed extensively to produce ultrathin strips in micromanufacturing, microelectronics, and other high precision engineering fields, very limited attention has been given to the deformation zone, which is a direct result of the material thickness reduction behavior during asymmetric rolling. In this study, theoretical analysis of the minimum thickness of single-roll-driven asymmetric rolling is performed by combining FE (finite element) and theoretical analytical models to complete a comprehensive investigation. Based on the FE model calculation results, the deformation zone contour varies with reduction ratio, strip thickness, and yield strength; the Fleck model can be used to describe single-roll-driven asymmetric ultrathin strip rolling when the thickness is small enough. Different from symmetric rolling, a cross-shear zone is inevitably formed during asymmetric rolling, but the cross-shear force resulting from asymmetric rolls decreases and approaches 0 with smaller strip thickness, smaller reduction ratio, and higher yield strength, which means the rolling status of single-roll-driven asymmetric ultrathin strip rolling is very similar to symmetric rolling when the strip reaches its limiting minimum thickness. Therefore, a minimum thickness model is developed for single-roll-driven asymmetric ultrathin strip rolling with different roll diameters, mean tensions and strip yield strengths, and the elastic modulus and Poisson ratio of the two rolls are considered. Eventually, the minimum thickness for single-roll-driven asymmetric rolling of ultrathin strips is estimated using the new minimum thickness model, with further experimental verification by the single-roll-driven asymmetric rolling of various materials, including aluminum, 304 stainless steel, and both non-annealed and annealed copper. Compared with experimental results, the model is shown to be a possible alternative for more accurate minimum thickness prediction in single-roll-driven asymmetric rolling. [ABSTRACT FROM AUTHOR]

Pipe rolling units (PRU) with three-high screw rolling mills are used to produce hot-rolled seamless pipes. Two units with rolling mills are operated in Russia: one is the TPA-160 mill at Pervouralsk Novotrubny Plant, JSC (Pervouralsk, Sverdlovsk oblast, Russia) and the second is the TPA-200 mill at Volzhsky Pipe Plant, JSC (Volzhsky, Volgograd oblast, Russia). Currently, increasing the technological capabilities of these PRUs is one major problem. It is necessary to expand the size and grade range, as well as utilize a non-traditional application of the sizing and rolling mills for screw rolling. To resolve these problems, the processes of reducing or plugless rolling of pipes on three-high screw rolling mills with increased reduction in diameter up to 25% are studied. The results of computer finite element simulation using QForm software are presented. The objective is to study the effect of the rolling process with increased diameter reductions on metal forming in the deformation zone and on changes of geometrical dimensions when reducing the capped blanks with different wall thickness on experimental-industrial mills. The capped blank ovality is quite important during metal forming when screw rolling. The ovality is the ratio of the feed radius when the metal comes in contact with the roll and the radius under the roll in the deformation zone cross section. The ovality characterizes the resistance of capped blank to deformations in inter-roll space. Reducing the thin-wall capped blanks is accompanied by large values of ovality, which makes the deformation process less stable. Therefore, the formation of shape defects (faceting) and end defects is possible during the plug rolling process. The rolling process ovality on the plug increases more intensely as compared with plugless rolling. The presence of plug limits the metal displacement in the axial direction and promotes metal displacement in the gaps between rolls. During plug rolling, it is necessary to use the rolls with shoulder, which make it possible to carry out the main reduction in the wall, thereby localizing the reduction zone on the plug and then decreasing the ovality of capped blanks. [ABSTRACT FROM AUTHOR]

The deformation in the inner region along the thickness of the heavy steel plate can be improved by snake rolling method. Then the microstructure and property will be refined and the crack in the inner region may be avoided. So the in-depth research on snake rolling method mechanics parameter modeling should be conducted to guide production. The rolling deformation zone will be divided into back slip zone, cross shear zone, front slip zone and reverse deflection zone according to the direction of the friction during the snake rolling process. The four zones may not exist at the same time. The boundary conditions of existence of the back slip zone, cross shear zone and front slip zone were established by calculating the position of neutral point by a special method. The calculating models which were used to calculate the snake rolling mechanical parameters including the rolling force and rolling torque were setup. The calculated models of unit compressive pressure in the four zones were setup by the slab method, and at this basis, the accurate calculating models of the rolling force and rolling torque were setup according to the composition of the rolling deformation zone and the boundary condition. The mechanical parameters were calculated by the analytic method and the numerical method, and the relative deviation is less than 5% which can satisfy the industrial requirement. The present analytical model can predict the characteristics during snake rolling easily and quickly and it is also suitable for online control applications. [ABSTRACT FROM AUTHOR]

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Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The upper cell layers of machined solid wood surfaces will usually be damaged and compacted due to cutting forces. The deformation zone may be instable due to temperature and moisture variations as a consequence of artificial surface treatment or environmental interaction. Therefore, an evaluation method of surface stability in this respect would be desirable. In the frame of the new developed surface roughness evaluation method an individual wetting procedure has been developed, whilst surfaces have been characterized by 3D roughness measurement. The stability of surfaces is characterized by appropriate roughness ratios measured before and after wetting. The core depth Sk of the Abbott parameters is the most sensitive indicator to any changes in the deformation zone. Different machining processes may produce surfaces with different stability but wood species have also definite influence on the surface stability, probably due to their density and moisture conduction properties. Latter is supported by the fact that the half-time of moisture evaporation from surfaces may differ considerably. In these experiments, planed and precision-planed surfaces were compared. According to the working principle of the precision planers the planing tool is held stationary whilst the work piece does the feeding motion, thus the blade produces a very thin slice. Using this machine, the machining roughness can be reduced to minimum as it is possible to avoid formation of cycloid arcs (like in case of traditional planing) and also possible to avoid dust formation (like in case of sanding). Investigations were conducted on Norway spruce (Picea abies), larch (Larix decidua), scots pine (Pinus sylvestris), sessile oak (Quercus petraea), black locust (Robinia pseudoacacia), aspen (Populus tremula) and beech (Fagus sylvatica). Black locust and the sessile oak have had most stable surfaces by both machining methods. The deformation zone of precision planed surfaces has been proven to be more stable than the one of planed surfaces for all wood species. [ABSTRACT FROM AUTHOR]

The paper describes the aspects of improving the pilger tube cold rolling technology in modern rolling mills. A review of the current effective methods for calculating the calibration of the working tools (dies, mandrel) of the cold pilger tube rolling mill (HPT) is given. A combined procedure for calculating the rolling force and power parameters along the length of the deformation zone is proposed, which accounts for the dies and mandrel calibration, elastic flattening of the rolls, contact friction, and tension of the work-piece. [ABSTRACT FROM AUTHOR]