Intermediate Rolling Research Articles

Texture development of pure Ti by rolling at various temperatures and its effect on sheet formability

This work investigated the effect of rolling temperature (25–800 °C) on rolling-texture development and sheet formability of pure Ti. The rolling temperature significantly affected the development of the typical transverse-direction (TD)-split basal texture in pure Ti sheet by altering the tilting angle of (0001) basal poles. Notably, a normal-direction (ND) basal texture, where the tilting angle of (0001) basal poles was approximately 0°, developed at an intermediate rolling temperature of 400 °C. This result is remarkable because the ND basal texture is rare in pure Ti. Formation of this unusual ND basal texture was attributed to significant activation of basal <a> slip. In contrast, a typical TD-split basal texture was dominant at the other rolling temperatures. Formation of this typical texture was attributed to pyramidal <c+a> slip. After subsequent recrystallization annealing, sheet formability was examined. Despite their different textures, the sheets previously rolled at the different rolling temperatures showed similar formability. This similarity occurred because any given texture could not simultaneously provide in-plane stretching uniformity and thinning capability during sheet forming. The present study suggests an important guidance for modifying texture of pure Ti sheets to effectively increase their formability.

Influence of intermediate principal stress and rolling resistance on the shearing response of sand: a micromechanical investigation

Influence of intermediate principal stress and rolling resistance on the shearing response of sand: a micromechanical investigation

An Analysis of Power Friction Losses in Gear Engagement with Intermediate Rolling Elements and a Free Cage

Currently, mechanical gears with cycloid engagement are increasingly used in mechanisms along with involute ones. In modern drive mechanisms, using pin gears and gears with intermediate rolling elements (IRE) is widespread, which simultaneously use cycloid gears. To a greater extent, pin gears are now being investigated, but IRE gears have their undeniable advantages. Many works are devoted to the study of cycloid toothing for certain gears, but the efficiency, especially that of IRE gears, has practically not been investigated. Therefore, the analysis of power losses in the engagement of a gear with IRE and a free cage (IREFC) is relevant. In this analysis, the authors of the work have used laws of mechanics, methods of energy flows and a secant normal. Mathematical expressions have been obtained to estimate slip speeds and power friction losses in the engagement of a gear with IREFC, and a formula has been derived to determine the efficiency of a mentioned mechanical transmission. The calculation of slip speeds and power losses at the points of contact of a rolling element with cycloid profiles of wheels for selected initial parameters of a gear with IREFC has been presented. The friction power and the overall efficiency of the entire gear engagement have also been calculated. This work shows that power friction losses at the points of contact of a rolling element with cycloid profiles of tooth wheels of a gear with IREFC are not the same. The friction power in the contact of a rolling element with a cycloid profile of a cam is an order of magnitude higher than the friction power in the contact of a rolling element with a cycloid profile of a crown.

Tailoring the formability and planar anisotropy of Al-Mg-Si-Cu-Zn alloys via cross hot rolling and two-stage cold rolling

Al-Mg-Si-(Cu) alloys have shown great potential in responding to the growing demand for automotive lightweight, but the limited formability and high planar anisotropy have always hindered their application. The present study designs a novel method for simultaneously improving the formability and planar anisotropy of Al-Mg-Si-Cu-Zn alloys by coupling cross hot rolling and two-stage cold rolling. The results have shown that the multi-scale distribution of secondary particles and strong Brass{011}<112> and S{123}<634> texture are induced by the designed cross hot rolling process, which weakens the recrystallization texture after solution treatment, especially Cube{001}<100> orientation. Meanwhile, the designed two-stage cold rolling process (intermediate cold rolling process with high reduction + final cold rolling process with low reduction) promotes the precipitation of unstable precipitates (Mg2Si and Q phase), and inhibits the formation of Copper{112}<111> orientation, which further weakens the recrystallization texture and results in the dispersion distribution of recrystallization texture. Accordingly, the formability and planar anisotropy of the Al-Mg-Si-Cu-Zn alloy are simultaneously improved without strength loss by coupling the designed cross hot rolling with two-stage cold rolling, and the influence mechanism of texture on r value has been analyzed by Visco-Plastic Self-Consistent (VPSC) model.

METODE PELAKSANAAN OVERLAY REKONSTRUKSI PADA PROYEK CIKOWOAN – KADUT (REGULER) DI STA 1 + 700 s/d STA 2 + 286

In terms of access to mobilization/demobilization and the location is very steep, the dump load is minimal due to poor access. Very high rainfall has resulted in further delays in the implementation of work. ACBC (Asphalt Concrete Binder Course) asphalt foundation and top layer or asphalt surface wear layer ACWC (Asphalt Wearing Course) for the material used, namely Asphalt Emulsion CSS -1 or SS -1 layer thickness (AC-BC) solid with a thickness of 0.6 cm with a loose thickness of 7.4 cm, the layer thickness (AC-WC) was solid with a thickness of 0.5 cm and a loose thickness of 6.4 cm. AC-WC compaction is divided into 3 parts, namely first compaction (breakdown rolling), second compaction (intermediate rolling), final compaction (final rolling). The first compaction is carried out when the temperature reaches 111 C to 102 C or about 0 – 10 minutes from the time the AC – WC is held. This ride uses a tandem roller with the number of tracks according to the trial compaction. The second compaction is carried out at a temperature of 102 C to 83 C or about 10-20 minutes since the AC-WC was held. This event uses a Pneumatic Roller with the number of passes according to trial compaction. The final compaction was carried out at a temperature of 83 C to 63 C or around 20-45 minutes since the AC-WC was held. This event uses a Pneumatic Tandem Roller with 12 to 15 passes. In the work of the Cikowoan – Kadut Road Improvement Reconstruction Project in Majalengka Regency, the tools used are Mini Excavators, Asphalt Tanks and assistive devices (asphalt sprayer), Dump trucks, Tandem combin rollers, Mini iron wheel compactor machines (baby roller), soil compactor machine.

Теоретическая оценка коэффициента полезного действия сферической шариковой передачи, работающей в мультипликаторном режиме

The paper considers issues of creating multipliers for the medium power wind generators. It proposes a basic kinematic diagram of the multiplier mechanism based on the spherical ball gear. The satellite makes a spherical motion during the gear operation, and the intermediate rolling elements mounted on the satellite in two rows are moving along the drive shaft and the housing sleeve treads. The gear under study makes it possible to realize large values of the gear ratios and speed multiplication factors with small overall dimensions and weight, respectively. An algorithm was developed for theoretical determination of the gear average efficiency in the reducer and multiplier modes depending on its geometric parameters and friction coefficients. The paper studies influence of the multiplier coefficient transfer, difference in the number of balls in the satellite rows and friction coefficient on the efficiency. Computer simulation results of the gear operation were received in the NX system, which confirmed the obtained theoretical dependencies.

High transport Jc in 7-filament Cu/Ag sheathed Ba0.6K0.4Fe2As2 tapes manufactured by ambient pressure sintering

In regard to iron-based superconductors (IBS), the multi-filament Cu/Ag composite sheathed Ba-122 tape is particularly attractive for industrial high-field applications owing to its prominent properties. By a cost-effective and scalable way, ambient pressure sintering, a high transport critical current density (Jc) of 7-filament Cu/Ag sheathed Ba-122 tapes reached 4.5 × 104 A cm−2 at 4.2 K and 10 T, whose corresponding engineering critical current density (Je) has achieved to 104 A cm−2. An optimized powder-in-tube (PIT) method was adopted aiming at overcoming the difficulty of ambient pressure sintering to obtain high-density superconducting core and grain alignment. Improvements in the manufacturing process, such as drawing without intermediate annealing and rolling from larger initial diameter to thinner tapes, have resulted in high grain connectivity and good c-axis texture, which are the major factors contributing to high Jc. Our results demonstrate that the ambient pressure sintering process is a viable method to fabricate long-length multifilamentary Cu/Ag composite sheathed IBS tapes with high Jc for practical high-field applications.

Effects of Intermediate Rolling on the Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloys

Effects of Intermediate Rolling on the Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloys

Effect of cooling rate on the order degree, residual stress, and room temperature mechanical properties of Fe-6.5wt.%Si alloy

The top side-pouring twin-roll casting (TSTRC) process was used to prepare a 100 × 1.7 mm non-oriented Fe-6.5 wt% Si alloy as-cast strip. The as-cast strip is directly rolled at 700 °C into 0.4 mm without the intermediate hot rolling step. This paper discusses the effects of different cooling rates in furnace cooling, air cooling, oil quenching, and water quenching on the order degree, residual stress, room temperature mechanical properties, and cold-rolled processing properties of Fe-6.5wt.%Si alloy after annealing of warm-rolled sheets are systematically investigated. Meanwhile, the effects of order degree, residual stress, and grain boundary element segregation on the mechanical properties were analyzed. The results show that as the cooling rate increases, the order degree of the Fe-6.5 wt% Si alloy decreases and the maximum residual tensile stress increases. The fracture modes of the furnace cooling, air cooling, and oil quenching samples are through-crystal disintegration fracture, and the fracture mode of the water quenching samples is an along-crystal fracture. The oil-quenched samples exhibit good room temperature plasticity due to the relatively low order degree and residual tensile stresses in the Fe-6.5wt.%Si alloy. Oil quenching improves the room temperature plasticity and cold rolling properties of Fe-6.5wt.%Si alloy warm rolled sheets, reduces edge cracks, and offers greater room temperature cold rolling processibility of the Fe-6.5wt.%Si alloy warm rolled sheets.

Development of an Algorithm for Computing the Force and Stress Parameters of a Cycloid Reducer

The paper is devoted to the development of an algorithm for the automated calculation of force characteristics of cycloid toothing when the initial parameters vary widely. The algorithm forms a structured data array that accelerates finding and outputting the necessary parameters and reduces the probability of error in determining these parameters. The algorithm serves the basis for a program that allows for the examination of the change in force and geometrical parameters in various combinations. The study includes the analysis of the dependence of forces and contact stresses in transmission toothing with intermediate rolling elements and a free cage on the initial parameters of this transmission. The obtained results will make it possible to select optimal combinations of initial parameters in order to minimize the force impact on the mechanism parts when designing modern compact mechanisms based on the cycloid with intermediate rolling elements and a free cage.

Features of design cold pilger mill tools for zirconium alloy tubes production

Method of design rolling tools’ grooves for manufacturing of zirconium alloy tubes is considered. The proposed methodology allows to clarify range different parameters calculated in design rolling tools. The described method will ensure compliance with current technical specifications and reduce the likelihood of defects during cold pilgering. The calculation algorithm for determination design parameters is implemented on the example of the intermediate rolling operation ∅65,0×11,9 mm ∅ → ∅32,2×5,3 mm.

Evolution of microstructure and crystallographic texture during cold rolling of liquid phase sintered tungsten heavy alloy

In this study, the evolution of microstructure and crystallographic texture of two-phase tungsten heavy alloy (almost pure tungsten embedded in nickel‑tungsten‑iron matrix) during cold rolling was investigated systematically. Electron back scatter diffraction studies reflected that the matrix phase accommodates more strain in the early stages of deformation and that as deformation progresses, the matrix phase exhausts its work hardening ability, resulting in the onset of micro-shear band formation. The tungsten phase on the other hand showed the presence of large orientation gradients accompanied with significant flattening and elongation of grains. At higher rolling reductions (effective true strain of −2.66), extensive shear bands spanning across several tungsten particles and the matrix were observed in the microstructure, which in turn had implications on the evolution of the crystallographic texture. It was observed that weak αb. c. c. (<110>∥RD) and γ fiber (<111>∥ND) emerge in tungsten at low to intermediate rolling reductions, and that αb. c. c. fiber strengthens much more than γ fiber at higher rolling reductions with prominent intensity at rotated cube position. For the matrix phase, a weak beta fiber (fiber connecting the brass {011}<211>, copper {112}<111>, and S {123}<634> orientations in the Euler space) was observed at low to intermediate rolling reductions, followed by strengthening of Goss and Brass orientations at higher rolling reductions.

Kinematic analysis of the intermediate body of the planetary gear with the engagement of the intermediate bodies

The method of kinematic research of planetary gear with intermediate rolling bodies is considered, taking into account the friction forces. One of the important issues related to the nature of the movement of the intermediate body relative to the mating surfaces has been resolved. It was revealed that sliding friction prevails in the contact between the separator and the intermediate body, and rolling friction prevails in contact with the surfaces of the teeth of the wheel. The law of changes in the instantaneous coefficient of efficiency in different phases of engagement is established. The obtained results of the work make it possible to improve the quality characteristics of wave transmissions with intermediate bodies. Keywords: transmission, intermediate body, advantages, geometry, kinetostatics, rolling friction, sliding friction, coefficient of efficiency. igwan@sibmail.com, avl2@tpu.ru, simaco@mail.tomsknet.ru

Research on the Possibility of Lowering the Manufacturing Accuracy of Cycloid Transmission Wheels with Intermediate Rolling Elements and a Free Cage

Purpose: In the present work, different combinations of fits and accuracies, in relation to the profiles of mating parts, have been analysed in order to assess the degree of the engagement of transmissions that contain intermediate rolling elements. The aim of this work is to determine which fits have decreased accuracy, but nevertheless provide a minimum manufacturing clearance for the transmission engagement in order to reduce the cost of parts production. Methods and materials: Considering the normal probabilistic distribution law in relation to the obtained dimensions of the manufacturing equipment, a combination of fits were selected using the incomplete interchangeability method, taking into account the peculiarities of the cycloid engagement in transmissions with intermediate rolling elements (IRE). Results: Having studied various combinations of fits of parts that are engaged in transmissions with intermediate rolling elements and a free cage (IREFC), a combination of fits for a “ring, rolling-element cam” were determined, in which a technological clearance of 3 µm is formed in the engagement. At the same time, cycloid disk profiles are manufactured according to the 9th tolerance grade, which reduces the laboriousness and cost of the production. Discussion. When reducing the manufacturing accuracy of cycloid disks, it is possible to obtain both very ample clearances and significant negative allowances. For example, having manufactured a ring with the H9 fit, rolling elements with h6 and a cam with js9, the maximum manufacturing clearance can reach 0.086 mm, while the clearance limits vary from 0.025 mm to 0.061 mm. Additionally, if mating parts are manufactured using a combination of K9-h6-js9 fits, a negative allowance varying from 0.014 mm to 0.026 mm will emerge in the engagement. Both described cases are unacceptable because both ample clearances and large negative allowances will negatively influence the working capacity of the mechanism. However, it is possible to select a combination of fits using the 9th tolerance grade of the basic parts, by which the parts will contact in the range from a small negative allowance of 1 µm to a clearance of 3–4 µm. Furthermore, if this is considered, taking into account the machine settings, it is possible to obtain parts according to the 9th accuracy tolerance grade and, at the same time, provide a clearance in the engagement that is almost equal to zero. Moreover, such a combination of fits is relevant for any transmission with IRE. This is a positive result because it reduces the laboriousness when manufacturing parts and, at the same time, provides high accuracy of the mechanism. Conclusions: It has been established that when lowering the accuracy of manufacturing transmission parts with IRE, both clearances and negative allowances may occur in the engagement, depending on the combination of fits. At the same time, it is possible to select such a combination of fits, by which the parts manufactured according to the 9th tolerance grade, will provide almost zero clearance of the engagement of the transmission. In this way, it is possible to reduce the cost of manufacturing the parts for gears with intermediate rolling elements and, at the same time, maintain a high accuracy of the transmission mechanism.

Investigation of the accuracy of the manipulator of the robotic complex constructed on the basis of cycloidal transmission

The object of research is modern robotic systems used in hotspots. In their arsenal, such mobile works are equipped with manipulators with high-precision hinges, which provide accurate positioning of the gripper (object of manipulation). Considering ground-based robotic complexes with a wheel or caterpillar base, the implementation of the process of manipulation on a stationary basis, a number of problem areas were identified that affect the accuracy of positioning. In the course of research and analysis of modern robotic complexes, their circuit and design of components and mechanisms that provide the necessary qualities and parameters. The problem of developing high-precision hinges is central to the creation of efficient ground-based robotic systems. The methodology of kinematic research of rotary hinges of the manipulator for the ground robotic complex is stated. The analysis of influence of deformations of material of impellers of not involute transfer on accuracy of positioning of a final subject is carried out. A kinetostatic analysis of the manipulator circuit was performed and the maximum moments acting in the hinged units on the drive unit were determined, which allowed to make a quantitative assessment using the Solidworks software package. The mathematical model of construction of transfer and definition of accuracy of a rotary knot for a ground robotic complex, with use of cycloidal transfer without intermediate rolling bodies is investigated and developed. Mathematical modeling and taking into account the features of mechanical processes occurring in the manipulator, allows to increase the technical level of robotic complexes. Ways of improvement are defined for maintenance of a progressive design of the manipulator that not only will satisfy necessary technical characteristics, but also will allow to simplify manufacturing technology. Modern technologies and materials (stereolithography, carbon fiber, superhard materials) make it possible to implement advanced designs of spatial drive systems. Therefore, work in this direction is relevant, as robotic mechanical complexes for special purposes are widely used when performing work in emergencies.

Modernization of a rolling table before gas cutting machine of bloom CCM

The results of the analysis of the design of the intermediate rolling table in front of the gas cutting machine of the four-strand continuous casting machine (CCM-1) of the electric steelmaking shop of JSC Ural Steel are presented. It is shown that as a result of exposure to high temperatures (due to the unsuccessful location of the gear motor near the high temperature zone), the operability of the gear coupling of the gear motor is often disrupted. To improve the performance of the intermediate rolling table CCM-1, it is proposed to modernise it by installing a pull-down device on each strand directly in front of the gas cutting machine, the working element of which is a drive roller located above the rolling table. Rotation of the roller is carried out from an individual electric drive, and its pressing to the workpiece &ndash; by means of a hydraulic drive through a system of levers. This makes it possible to perform all 28 rollers of the rolling table non-drive ones, without changing their location. As a result of the modernization of the intermediate rolling table CML-1 in front of the gas cutting machine, it was possible to simplify its design and reduce the complexity of maintenance and repair by 64 hours per year. Replacing 28 drive rollers with non-drive rollers increases the reliability of their operation, allows you to increase the repair period of operation and thereby reduce the cost of operating costs. In addition, reducing the number of electric motors from 28 to 4 provides significant energy savings. Calculations show that the implementation of design solutions leads to a reduction in the cost of one ton of steel by 0.05 %, an increase in product profitability by 0.19 % and an increase in labor productivity by 0.41 %. Additional capital expenditures of about 1 million rubles are recouped in less than 3 months.

ОПРЕДЕЛЕНИЕ КОЭФФИЦИЕНТА НЕРАВНОМЕРНОСТИ МЕЖДУ РЯДАМИ ТЕЛ КАЧЕНИЙ В ВОЛНОВОЙ ПЕРЕДАЧЕ С ПРОМЕЖУТОЧНЫМИ ТЕЛАМИ КАЧЕНИЯ

The work is devoted to the topical problem of designing rotary actuators based on harmonic gears with intermediate rolling elements (HGR). The theoretical dependences are presented, which make it possible to determine unevenness ratio of the load distribution between the rows of rolling elements in the HGRE. The results of service life tests of the HGRE and modeling by the finite element method, characterizing the uneven distribution of the load between the rows of rolling elements, are given. A refined dependence of the calculation of the diameter of the rolling bodies in the HRGE is proposed, which makes it possible to consider the uneven distribution of the load between the rows of rolling elements.

A Geared Motor Design Based on Wave Transmission with Intermediate Rolling Bodies

In this paper, we substantiate of the possibility of reducing the weight and size characteristics of electric drives operating under high loads. To solve the problem, a geared motor design was developed. Unlike the existing analogues, the proposed design solutions are based on the use of wave transmission with intermediate rolling bodies, which allows obtaining high values of the gear ratio at small dimensions. The results obtained may be used in the development of small-sized electric drives for moving parts of robotic and mechanical systems.

MODELIZACIÓN Y COMPORTAMIENTO DINÁMICO DE UN RODILLO VIBRATORIO PARA LA COMPACTACIÓN DEL SUELO BASADO EN EL MÉTODO DE PARÁMETROS CONCENTRADOS

The interaction between a roller and soil is a complex dynamic problem that has become an important theoretical requirement constraining roller design and the application of an advanced roller in the development of intelligence and informatization in the roller industry. To clarify the interaction mechanism between a drum and soil during the rolling process, a two-degree-of-freedom (DOF) lumped-parameter model for a vibratory roller-soil coupling system was established with consideration of the contact state of the soil and the drum. Based on the dynamic equation of the system, the effects of the soil and the excitation force on the dynamic behavior of the roller were revealed by introducing certain parameters. The results show that the natural frequencies of the system increase obviously from the beginning to the intermediate rolling stage, but the natural frequencies have only slight increases after the intermediate rolling stage, while the drum stays in contact with the soil. Compared with the beginning stage and the intermediate stage, it can be found that the first and second natural frequencies increase by 0.29 times and 0.43 times, respectively. With the increase of the soil compactness, the possibility of the vibration state of the roller changing from stability to chaos increases. Increasing the frequency of the excitation force and decreasing the amplitude of the excitation force can effectively improve the vibration of the system, and the dynamic behavior of the system is more sensitive to the frequency. The modeling and dynamic analysis of a vibratory roller are presented in this study. The model can be used for the theoretical analysis of the vibration recognition of the roller, and the conclusions provide a reference for the design and application of a roller. Keywords: Vibratory roller, Lumped-parameter model, Dynamic behavior

Effect of Thermo-mechanical Treatment on High Temperature Tensile Properties and Ductile–Brittle Transition Behavior of Modified 9Cr-1Mo Steel

In the present work, a modified 9Cr-1Mo steel is subjected to normalizing and tempering treatment with or without an intermediate rolling, which was carried out at 1050 °C in austenitic phase and 550 °C in metastable austenitic phase. The tempering was carried out at 700 °C and 750 °C to improve the strength by precipitation hardening and refining the microstructure. The ductile to brittle-transition temperature (DBTT) and tensile properties have been evaluated at 20 °C, 550 °C and 650 °C for the material subjected to various thermomechanical treatments. Rolling performed in austenitic phase showed improvement in the upper shelf energy and reduction in the DBTT compared with the material rolled in metastable austenitic phase. Rolling in metastable austenitic phase improved the yield strength at elevated temperature (39 pct at 20 °C, 31 pct at 550 °C and 91 pct at 650 °C) and was accompanied by a reduction in ductility (21 pct at 20 °C, 32 pct at 550 °C and 35 pct at 650 °C) compared with the as-received condition. The influence of grain size, low angle boundaries and precipitates on DBTT and high temperature strength has been studied using EBSD and TEM analyses. An increase in high temperature strength is found to increase with the area fraction of fine M23C6/MX precipitates, whereas low angle boundaries and effective grain size influenced the DBTT behavior. The combined effect of precipitation strengthening and strain hardening leads to improvement in the high temperature mechanical strength while maintaining adequate toughness. The effect of aging (for 72 hours at 650 °C) on heat-treated and -rolled samples showed a small decrease in yield strength at 20 °C. A decreasing trend of fracture toughness is observed with the increase in yield strength.