Bar Rolling Research Articles

Technical, Field, Economic and Energy Comparison of Cutter Bar Maize Header With Snap Roll Maize Header

In India, most of the maize combine harvester currently being used employs snap roll type header. This type of header is costly, dependent on row spacing of maize crop and causes losses at headlands during turning. Moreover owing to its heavy weight its frequent lifting and downing during harvesting season causes hydraulic leakages in certain sections of combine. Therefore to overcome these problems a new light weight cutter bar Maize header is developed and evaluated for maize crop. The performance evaluation of the cutter bar type maize header is done in a dislodged and a partially lodged (30-40%) maize crop. For lodged crops, the header losses varied from 19.18-26.71% and for dislodged crops it was varied from 5.29-10.15% respectively. The cylinder losses for dislodged crop varied from 2.70-2.86% and for lodged crop it varied from 0.85-2.04%. The mean cleaning efficiency for lodged and dislodged maize crop was found as 88.87% and 90.58% respectively. The grain damage for lodged and dislodged crop was observed as 8.31% and 5.94% respectively. The trash content for lodged and dislodged crop was 2.75 and 3.45% respectively. The performance of snap roll and cutter bar was also done. Total losses with snap roll header were higher as 15.06% and lower for cutter bar as 10.85%. The brokens were higher for cutter bar as 5.94 and lower for snap roll as 3.45%. The trash content was 3.45% for cutter bar header and 2.24% for snap roll header. The total energy input in snap roll header, cutter bar maize header and maize dehusker cum sheller were 2360.05, 1970.90 and 3770.48 MJ/ha respectively.The cost of operatin with cutter bar maize header, snap roll maize header and maize dehusker cum sheller were 53.62 $/ha, 68.73$/ha 187.32 $/ha respectively.

Crash rates of convertible cars

Objective Convertible cars have existed since among the first automobiles, and the lack of substantial roof structure creates some safety concerns. Though crash tests have demonstrated that convertibles can resist excessive intrusion in front and side crashes and that strong A-pillars and roll bars can help maintain survival space in rollovers, little work has been done examining the real-world crash experience of these vehicles. The objective of this study was to compare the crash experience of recent convertibles with nonconvertible versions of the same cars using the most recent crash data. Methods Crash and exposure data were obtained from the U.S. Department of Transportation and IHS Markit, respectively. Rates of driver deaths and police-reported crash involvements were compared for 1- to 5-year-old convertible cars and their nonconvertible versions during 2014–2018. Exposure measures included registered vehicle years (RVY) and vehicle miles traveled (VMT). These rates were compared using the standardized mortality ratio to account for possible differences in exposure distribution. Crash circumstances (e.g., point of impact, rollover, ejection) and behavioral outcomes (e.g., speeding, alcohol impairment, seat belt use) were compared for drivers killed in crashes. Results Convertibles had lower driver death rates and police-reported crash involvement rates on the basis of both RVY and VMT. However, the differences in driver death rates were not statistically significant. Driver deaths per 10 billion VMT were 11% lower for convertibles, and driver involvement in police-reported crashes per 10 million VMT was 6% lower. On average, convertibles were driven 1,595 fewer miles per year than the nonconvertible versions of these cars. Among fatally injured drivers, convertibles had slightly higher rates of ejection, and behavioral differences were minimal. The number of rollovers was small and their rate did not substantially differ between convertibles and their nonconvertible versions. Conclusions Safety concerns associated with convertibles’ retractable roof structures were not supported by the results of this study.

Surface topography after deep rolling with milling kinematics

Deep rolling is a machining process which is used to decrease roughness and to induce compressive residual stresses into component surfaces. A recent publication of this research group showed possibilities to predict the topography during deep rolling of bars in a lathe. Although deep rolling can be used in a milling machine to machine flat specimens, it is still unclear, whether the topography can be predicted to a similar extend using this application. To investigate the influence of the machining parameters on topography, three experimental stages are performed in this paper on cast AlSi10Mg. First, single-track deep rolling experiments are performed under variation of the deep rolling pressure p_w to find the relationship between p_w and the indentation geometry. Here, a logarithmic relationship between deep rolling pressure and the indentation characteristics could be found that achieved a relatively high agreement. In the second stage, surfaces are prepared using multi-track deep rolling. Here, the deep rolling pressure p_w and the lateral displacement a_b are varied. The multi-track rolled surfaces were compared to an analytical model for the calculation of the theoretical roughness that is based on the logarithmic relationship found in the first experimental stage. Here, the limits of the analytical prediction were shown because high similarities between predicted and measured surfaces only occurred for certain deep rolling pressures p_w and lateral displacements a_b. To further investigate the limitations of this procedure, a novel tool concept, which utilizes the rotation of the machine spindle, is used in the third stage. Here, the generated surface can also be interpreted as a periodic sequence of spheric indentations as shown in the second experimental stage, whereas the measured surfaces differed from the expected surfaces. As a result of this paper, the predictability of the surface topography after deep rolling of flat specimens is known (minimum pressure p_{w,minAlSi10Mg} = 5 MPa and minimum lateral displacement a_{b,minAlSi10Mg} = 0.25 mm) and also first results regarding the final topography after using the novel tool concept are presented.

Prediction of ductile fracture in skew rolling processes

This paper begins with a review of the literature regarding the modelling of skew rolling processes, with a special focus on the problem of material fracture. Numerical modelling is performed to compare stresses and strains in the cross sections of bars produced by skew rolling with the use of two and three rolls. It has been found that the two-roll skew-rolled bars are more prone to the occurrence of fracture in their axial zone. It is proposed that cracking in skew rolling processes be predicted with the use of classical fracture criteria. The accuracy of crack prediction by these criteria depends on the correct determination of the critical damage. The critical damage in skew rolling processes can be determined by two tests: rotary compression of a tapered specimen (when a process is performed with two tools) or rotary compression of a disc-shaped specimen in a cavity between the tools (when a process is performed with three tools). Six fracture criteria and a new test of rotary compression of a tapered specimen are employed to investigate fracture in a two-roll skew rolling process for producing cylindrical bars made of 100Cr6 grade steel. It has been found that stress-based criteria are more suitable for modelling fracture due to their lower sensitivity to temperature variations in the axial zone of rolled bars.

Reducing Crop Length of Rolling Material Using Predictive Model Analysis

In steel bar rolling, molten metal in the casting process is solidified into a bloom with a large square cross section, which is then made into a billet. Management of the process yield during rolling is very important. In particular, the length and weight of the crop generated at the front/rear end of the material during rolling vary; however, various studies are being conducted to reduce this to 1% of the actual material yield. In this study, we investigated the factors influencing the crop fish tail and identified new operating parameters to derive optimal operating conditions. In particular, to predict the crop length, we conducted several predictive model analyses to identify the factors affecting the crop length. We investigated the factors related to the length of the crop fish tail, established a length prediction model based on correlation, and optimized the operating conditions based on the prediction model. The upper and lower layers of the furnace soaking zone for the hard steel bloom were operated at 1473, 30 K lower than the existing 1503 K. As a result, the length of the crop fish tail was 147.3 mm, shortened by approximately 13.1 mm, compared to the existing 160.4 mm.

Comparative analysis of stress-strain state of bars from aluminum alloys A2024 and A7075 processed by RSR based on FEM modeling

In this article the analysis of temperature conditions and stress–strain state during radial-shear rolling (RSR) of bars from industrial deformed aluminum alloys A2024 and A7075 was carried out. The RSR was made for four different variants of elongation ratio µ for each alloy: 1.2, 1.6, 2.0, 2.4. It is shown that for the alloy A2024 in the zone of maximum reduction, the growth of elongation ratio leads to the increase in the temperature difference, and for A7075, the temperature difference decreases. After rolling the temperature of bar increases due to the deformation heating in average by 5–30°C in dependence on reduction per pass. At deformation with µ <2.0 the axis zone of bars is characterized by the presence of positive average stresses. The analysis of stress triaxiality parameter showed that the alloy A2024 has a large margin of technological plasticity in comparison with the alloy A7075 when deformed by the RSR method with similar parameter.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ РЕЖИМОВ ТЕРМИЧЕСКОЙ ОБРАБОТКИ НА СТРУКТУРУ И МЕХАНИЧЕСКИЕ СВОЙСТВА ПРУТКОВ ИЗ СПЛАВА ВТ47

The article presents the results of a complex of studies on the analysis of the microstructure, as well as the determination of the mechanical properties under tension, shear resistance and upsetting at room temperature of rolled bars made of pseudo-β-titanium alloy VT47. A comparative analysis of the obtained research results is carried out, showing the dependence of the mechanical properties of rolled bars on various heat treatment modes, aimed at providing increased technological plasticity of the material and strengthening heat treatment.

On the cleavage hoop stress responsible for crack path deflection and notch-induced anisotropic fracture in cold drawn pearlitic steel: Revisiting John Ford’s Monument Valley

In this paper a study is presented of the fracture behaviour in the presence of notches of high-strength pearlitic steel with different cold drawing degree. To this end, axisymmetric notched samples with a circumferentially-shaped notch of very distinct geometries (sharp and blunt, deep and shallow) were taken from wires with different levels of drawing from the initial hot rolled bar (not cold drawn at all) to the final commercial product (prestressing steel wire: heavily cold drawn). Experimental results show that cold drawn steels exhibit a markedly anisotropic fracture behaviour in the form of fracture path deviation from the original transverse fracture path perpendicular to the wire axis or cold drawing direction. Present paper proposes a key variable governing the notch-induced anisotropic fracture process: the cleavage hoop stress as the relevant factor promoting this sort of fracture path deviation in the most heavily cold drawn pearlitic steel wires

Numerical modeling of hydrogen embrittlement of pearlitic steel in the presence of blunt notches

This paper offers a numerical modeling of hydrogen embrittlement and notch tensile strength of high-strength pearlitic steel (supplied in the form of hot rolled bars) in the presence of blunt notches, by using the finite element method in order to determine how the notch depth influences the concentration of hydrogen in the steady-state regime for different loading values. Numerical results show that the maximum hydrostatic stress location (towards which hydrogen is directed by a mechanism of stress-assisted diffusion) shifts from the notch tip to the inner points of the specimen under increasing load, even reaching the sample axis for the most elevated levels of externally applied stress.

Evolution of non-metallic inclusions with cold drawing in progressively cold drawn eutectoid pearlitic steel wires

This article focuses on the analysis of the evolution of inclusions present in eutectoid pearlitic steel subjected to a real cold drawing process. To this end, wires belonging to different stages of the manufacture chain were studied, starting from an initial hot rolled bar (not cold drawn at all). In addition to the information obtained through visual inspection, a quantitative analysis of the micro-defects generated by these inclusions has been carried out. The analysis has been performed using materialographic techniques, scanning electron microscopy (SEM) and the image analysis program (AnaliSYS 3.1®)..

Dual-Objective Mixed Integer Linear Program and Memetic Algorithm for an Industrial Group Scheduling Problem

Group scheduling problems have attracted much attention owing to their many practical applications. This work proposes a new bi-objective serial-batch group scheduling problem considering the constraints of sequence-dependent setup time, release time, and due time. It is originated from an important industrial process, i.e., wire rod and bar rolling process in steel production systems. Two objective functions, i.e., the number of late jobs and total setup time, are minimized. A mixed integer linear program is established to describe the problem. To obtain its Pareto solutions, we present a memetic algorithm that integrates a population-based nondominated sorting genetic algorithm II and two single-solution-based improvement methods, i.e., an insertion-based local search and an iterated greedy algorithm. The computational results on extensive industrial data with the scale of a one-week schedule show that the proposed algorithm has great performance in solving the concerned problem and outperforms its peers. Its high accuracy and efficiency imply its great potential to be applied to solve industrial-size group scheduling problems.

Prediction of Surface Wrinkle Defect of Welding Wire Steel ER70S-6 in Hot Bar Rolling Process Using Finite Element Method and Experiments

High quality products are demanded due to increasingly fierce market competition. In this paper, the generation of surface wrinkle defect of welding wire steel ER70S-6 was studied by the combination of the experimental method and finite element simulation. Firstly, a thermal compression test was conducted on the Gleeble-3500 thermosimulator under different strain rates and temperatures and a strain dependent Arrhenius-type constitutive function was employed to fit the flow stress–strain curves obtained from the experiments. Then, the elastoplastic constitutive relationship was implemented using radial return mapping algorithm by means of the user subroutine VUMAT of Abaqus/Explicit. A new instability criterion was proposed to predict the possibility of the surface wrinkle defect during the multipass hot bar rolling process. In order to verify the reliability of the finite element model of the six-pass continuous rolling process, the simulated results were compared with experimental data. Finally, the effects of groove width and groove radius on the billet were investigated by the orthogonal test method, and the friction coefficient and rolling temperature. The results show that the groove width and groove radius are key factors to suppress the surface wrinkle defect. Decreasing the groove width can be beneficial for improving the surface quality and reducing the fillet radius. The optimized combination of the rolling process parameters was further applied in an industrial test and the surface quality of the billet was greatly improved.

Heuristic Scheduling of Batch Production Processes Based on Petri Nets and Iterated Greedy Algorithms

Wire rod and bar rolling is an important batch production process in steel production systems. A scheduling problem originated from this process is studied in this work by considering the constraints on sequence-dependent family setup time and release time. For each serial batch to be scheduled, it contains several jobs and the number of late jobs within it varies with its start time. First, we model a rolling process using a Petri net (PN), where a so-called rolling transition describes a rolling operation of a batch. The objective of the concerned problem is to determine a firing sequence of all rolling transitions such that the total number of late jobs is minimal. Next, a mixed-integer linear program is formulated based on the PN model. Due to the NP-hardness of the concerned problem, iterated greedy algorithm (IGA)-based methods by using different neighborhood structures and integrating a variable neighborhood descent method are developed to obtain its near-optimal solutions. To test the accuracy, speed, and stability of the proposed algorithms, we compare their solutions of different-size instances with those of CPLEX (a commercial software) and four heuristic peers. The results indicate that the proposed algorithms outperform their peers and have great potential to be applied to industrial production process scheduling. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This work deals with a scheduling problem of a batch production process, i.e., wire rod and bar rolling, which is modeled by a Petri net (PN). Due to the NP-hardness of the concerned problem, four iterated greedy algorithm-based methods are developed to solve it. The proposed methods are validated and tested by comparing their solutions with those of four heuristic peers and the exact ones (when available via CPLEX). Extensive experimental results show that they can fast solve one-week-scale instances with better performance than their peers’, thereby proving the readiness to put them in industrial use. When solving a one-month-scale instance, the proposed methods show much better performance than others.

Analyses of the Effect of Clamping Distance on Stress and Roll Stiffness of Anti Roll Bar

Analyses of the Effect of Clamping Distance on Stress and Roll Stiffness of Anti Roll Bar

Experimental and numerical analyses of 45 steel during three dimensional severe plastic deformation (3D-SPD)

Due to the limitation of huge forming load, inhomogeneity of plastic deformation, and small volume of deformation region, it is difficult to prepare bulk ultra-fine grains material (UFGM) with industry size by the existing severe plastic deformation (SPD) methods. In this study, a novel SPD method, namely 3D-SPD, was proposed. By establishing finite element model, the distribution of material flow, restraining to Mannesmann effect, and comparison of load were discussed. Based on the self-developed rolling mill, the corresponding experiments were conducted. The experimental results reveal that the buck ultra-fine grains material of 45 steel was obtained under the condition of feed angle 21°, cross angle 15°, cone angle 5°, reduction rate 50%, and roll speed 30 rpm. The average grain size was refined from 46 to 0.8–4 μm. The tensile test results indicate that the yield strength and tensile strength of the rolled bar were significantly improved.

Study of the Manufacturability of Production and Properties of Welding Wire from Alloy 1580

The results of studies on the production of welding wires with a diameter of 2.5 and 3.3 mm from alloy 1580 are presented. To compare the manufacturability of the processing, various methods were used to obtain billets for drawing with a diameter of 8-12 mm: the traditional method of direct hot extruding (discrete); combined rolling-extruding method; and ingotless rolling-extruding method (continuous). The developed modes of bar rolling, drawing and annealing made it possible to obtain prototypes of wire in laboratory and industrial conditions. It was found that alloy 1580 is highly manufacturable both with the traditional method of pressure treatment (extruding) and with combined rolling-extruding methods. It was revealed that the application of all methods makes it possible to obtain billets with the level of mechanical properties necessary for further multi-operation processing. Based on the results of research obtained in laboratory conditions, rational drawing modes for industrial wire production have been developed. As a result of bay drawing, pilot batches of welding wire with a diameter of 3.26 and 2.47 mm from alloy 1580 were obtained, which was successfully used for welding sheet metal.

Specific Features of the Structure, Properties, and Technological Plasticity of Metal Products Made of 03Kh22N5AM3 Corrosion-Resistant Duplex Steel

We consider specific features of formation of the structure and properties of 03Kh22N5AM3 corrosion-resistant duplex steel in the process of deformation and thermal treatment of rolled milled bars. We analyze the influence of the chemical composition and the conditions of smelting, casting, hot deformation, and heat treatment on the formation of intermetallic phases, which reduce the ductility of the metal. We also give recommendations aimed at increasing the impact toughness of 03Kh22N5AM3 steel at –40 and –46°C.

Identification of regularities of changes in energy-power parameters depending on the design of the roller node of a new radial-shear mill by computer simulation

This paper proposes a radial-shear mill (RSM) of a new design, which allows by rolling or rolling and pressing operations obtaining high-quality rods and wires. In addition, it proposes the method of computer calculation of the energy-power parameters of bar extrusion at the RSM of the new design. Mathematical dependences and calculation algorithm were described, which allow calculating energy-power parameters of the combined bar manufacturing process at a given level of technological parameters. Based on the results of analytical studies and computer modeling, the energy-power parameters were defined and analyzed, in addition, the laws of their changes were determined. It is shown that, regardless of the alloy grade or type, when rolling billets on a new RSM with smooth rolls, the strain force is larger in magnitude compared to rolling in helical rolls. It was found that, in comparison with rolling of bars in smooth and helical rolls, their processing by a combined rolling-pressing process leads to an increase in the deformation force of alloys M1 and D16 by 1.1–1.15 and 1.15–1.3 times, respectively. It is shown that during the deformation of the rods on the new RSM, by controlling the paths of the metal flow in the deformation zone, intensive grinding of the metal structure can be achieved. It was found that when pressing the bars on the new RSM, the temperature of the workpiece increases up to 420 °С, which leads to a sharp decrease in the force required for deformation. The nature of the temperature distribution of the pressed metal in the deformation zone was determined. The adequacy of the models was proved by comparing calculated values of the power parameters of extrusion, obtained by engineering technique and numerical simulation

Effect of free-end torsion on microstructure and mechanical properties of AZ31 bars with square section

In this study, a rolled AZ31 bar with square section was used. The reciprocating torsion was performed to maintain the shape of the sample. The microstructure evolution of AZ31 bar during torsion and its influence on compressive anisotropy were investigated in detail. Results showed that reciprocating torsion can simultaneously enhance yield strength in three compressive directions, and reduce compressive anisotropy. Reciprocating torsion generated profuse dislocations and {10–12} twin boundaries to harden the micro-hardness and yield strength. Reciprocating torsion can also generate new texture component which is mainly from the orientation of newly generated {10–12} twins. The new twin-structures will be responsible for the reduction in compressive anisotropy. Moreover, uneven deformation features in twisted sample were systematically investigated.

FEM-Based Methodology for the Design of Reduced Scale Representative Experimental Testing Allowing the Characterization of Defect Evolution during Hot Rolling of Bars

Defects generated during the casting process of steel can be reduced by forming processes such as hot rolling. During these processes the effective strain, the temperature, the stress state and the alternation of the forming direction all influence the defect evolution. Analytical or numerical models are available in the literature to predict the defect evolution. However, experiments have to be carried out to identify the parameters of these models. Thus, the quality of the identification depends on the representativeness of the experiments with respect to the industrial forming process. This paper proposes a methodology to design reduced scale experiments with an improved level of representativeness. This methodology consists first in the identification of the thermomechanical parameters driving the defect evolution and the quantification of these parameters in the industrial process by FEM simulation. These last results are then utilised as criteria for the representative experiment design. In this work the methodology is applied to the rolling of bars. The representative experiment consists of successive forming operations of a cylindrical sample between shaped anvils reproducing the roll shape at a 1:10 scale. A validation is finally achieved by reproducing qualitative results concerning the evolution of voids in the vicinity of hard inclusions.