Metal Rolling Research Articles

An ultra-low frequency vibration energy harvester with zigzag piezoelectric spring actuated by rolling ball

This paper presents an ultra-low frequency vibration energy harvester using a zigzag piezoelectric spring oscillator, which consists of two piezoelectric zigzag springs and a rolling metal ball. The metal ball rolls and drives the piezoelectric springs to deform to harvest energy when a slight vibration occurs in the external environment. The natural frequency of zigzag spring oscillator piezoelectric energy harvester (ZSO-PEH) is related to the length of the spring and the weight of the ball, correlation analysis is carried out by theoretical derivation and ANSYS simulation. It is found experimentally that the proposed device offers efficient energy output in ultra-low frequency excitation. A maximum output power of 5.68 mW is achieved under the best matching resistance of 5.1 kΩ at the excitation frequency of 3 Hz. The performance of energy harvester can be optimized by adjusting the length of the spring and the mass of the ball. The results show that the proposed piezoelectric energy harvester has the potential to power low-power electronic devices and wireless sensor nodes.

Ultrasonic technique for measurement of oil-film thickness in metal cold rolling

ABSTRACT Lubrication is essential in metal cold rolling operation to regulate friction at the metal–roll interface, reduce energy loss and improve the product surface finish. A novel non-intrusive pitch-catch technique, based on the reflection of ultrasound, was employed on a pilot mill to evaluate oil-film thickness at the metal–roll interface during the metal cold rolling operation. During the metal rolling process, oil-film thickness was measured under varying rolling load and rolling speed. The oil-film thickness increases as the roll speed increases and reduces as the rolling load increases. The values of oil-film thickness obtained from this non-intrusive ultrasonic technique agree with theoretical values. This study is a proof of concept and has shown promising results. If further developed, the technique could be employed for in situ monitoring of lubricant during rolling operation in metal rolling industries.

Evaluating the efficiency of Nostoc commune, Oscillatoria limosa and Chlorella vulgaris in a phycoremediation of heavy metals contaminated industrial wastewater

Industrial wastewater treatment by microalgae is an eco-friendly technology for improving the quality of wastewater. This study evaluated the removal of heavy metals (Cu, Fe, Ni, Pb, Cd and Zn) in wastewater collected from a metal rolling mill industry using Nostoc commune, Oscillatoria limosa and Chlorella vulgaris. Metals were determined using Atomic Absorption Spectroscopy (AAS). Other wastewater parameters determined using the standard procedure were pH, dissolved oxygen (DO), biological oxygen demand (BOD), Cl−, SO42−and NO3-. Data collected were analyzed for descriptive statistics. The results of the raw industrial wastewater were 8.50±0.07 mg/L for Cu, 3.51±0.80 mg/L for Fe, 0.16±0.01 mg/L for Ni, 1.31±0.11 mg/L for Cd and 2.48±1.00 mg/L for Pb. These values were above the permissible standards of the National Environmental Standards and Regulations Enforcement Agency (NESREA) for wastewater. After 45 days of treatment, removal efficiency for heavy metals by the microalgae ranged from 10% (Cu) to 90% (Pb). Despite the appreciable levels of metal removal in wastewater by the microalgae; the treated wastewater still exhibited metal values (except Zn) greater than the permissible limits of the NESREA. The effectiveness of the three microalgae for removing metals followed similar pattern. The present study showed the promising potentials of the three microalgae in wastewater treatment.

FINITE ELEMENT ANALYSIS OF CHROMIUM AND MOLYBDENUM ALLOYED STEEL BILLETS FORGED ON MULTI STEP PROCESS USING SIMUFACT FORMING

ABSTRACT Simufact Forming covers the complete spectrum of working on forming technologies like rolling, forging, and sheet metal forming. In this paper, finite element comparative analysis was performed on two chromium- and molybdenum-alloyed steel billets, namely 42CrMo4 and 16CrMo4 alloyed steels, using multi-step forming process of hot closed die forging process using Simufact Forming software. 42CrMo4 alloy steel is most commonly used in making of automobile components, and 16CrMo4 alloyed steels are commonly utilised in the area of ship building, airplanes, etc. While working with these materials, with the help of forging process, lot of stresses, strains and temperatures will develop. In this paper, three state variables, namely effective plastic strain, equivalent stress and temperature, for two materials at the end of multi-step forming processes like chamfering, preforming and final forging stages are evaluated and compared. In cooling process, the initial temperature of billet is maintained at 1250°C for both materials. Finally, comparative analysis of two alloyed steel billets was done by considering three-state variables.

Efficiency and convergence of China’s export trade embodied carbon emissions

Based on the input-output data from 2002 to 2017, this paper combined the three-stage DEA model with the non-competitive I-O model and measured the embodied carbon efficiency of export trade in China’s 26 product sectors, and further investigated its influencing factors and convergence issues. The results of the study showed that: ①The embodied carbon efficiency of export trade in China’s overall product sector demonstrated a positive development trend from 2002 to 2017, and this positive trend was more obvious after the implementation of conservation culture construction in 2012. But the differences of embodied carbon emission efficiency level among the product sectors were still significant. ② Measured by the K-means clustering analysis method, this study found that agriculture, other service industries, wholesale and retail industries, catering industry, construction industry and manufacturing industry with strong innovation ability were mostly concentrated at high and medium efficiency levels, while industrial sectors with resource dependence and high energy consumption, such as metal smelting and rolling processing industries, non-metallic mineral products industry, and coal mining industry, were at a low efficiency level. ③ All product sectors had σ convergence, absolute β convergence and conditional β convergence during 2002–2010 and 2010–2017, and the level of each product sector in 2010–2017 was higher than that in 2002–2010 according to the perspective of convergence speed and degree of convergence. ④ Technological progress had not fully played a role in suppressing energy consumption and improving the efficiency of embodied carbon efficiency, and it would also widen the gap between the embodied carbon emission efficiency levels of various product sectors. The expansion of trade scale could effectively improve carbon emission efficiency and narrow the gap between sectors. Environmental regulation could effectively promote the improvement of embodied carbon emission efficiency but would widen the level gap between sectors. These findings indicate that China needs to build a sound environmental regulation system for the development of low-carbon trade, continue to reasonably expand the scale of trade, eliminate backward industries with production capacity, vigorously develop low-carbon technologies such as new energy, strengthen the exchange of low-carbon technologies and industrial cooperation among sectors, and promote coordinated development among industries.

Mathematical model of forecast of strength of low carbon steel

Introduction. The use of different mathematical approaches to assessing and forecasting the quality characteristics of materials for different purposes is always relevant. The urgency of solving problems and problems of modern materials science with the use of methods of mathematical modeling allows to optimize technological processes of production, to determine in a short period of time the set parameters with minimal time and material costs. In the work using the method of regression analysis, the strength criteria of low-carbon low-alloy steel depending on the characteristics of the structure were evaluated. Materials and methods. Samples of Ст3пс steel grade made of a circle with a diameter of 24 mm were selected as the material for the study. The structure and mechanical properties were investigated at three reference points: at a distance of 0 mm from the center of the sample, 6 mm from the center of the sample and 12 mm from the center of the sample. The steel was investigated in the state of factory delivery, and after two modes of heat treatment to obtain ferritic-perlite and bainite structure. The following properties were determined: microhardness, tensile strength and yield strength, hardness and toughness at room temperature. The results of the experiment. Models for estimating mechanical properties were obtained using regression analysis. Models describing the relationship between the microhardness of pearlite and its area (R2 = 0.8366) in the state of factory delivery have a relatively high correlation coefficient; the score and the ultimate strength (R2 = 1.0) and yield strength (R2 = 0.8669) of steel after cooling in an oil medium; hardness and area of pearlite after hardening steel in the pearlite region (R2 = 0.7215). Conclusions. The practical significance of the work performed is the ability to perform a rapid analysis of the properties of rolled metal from steel Ст3пс based on determining the area of the structural elements and their scoring. However, it should be noted that the existing discrepancy between the results of the experiment and the forecast using the obtained models may be due to the influence of other factors. Such factors include the influence of chemical composition, incompleteness of formal axiomatics, which occurs when estimating the geometry of complex structural elements.
 Keywords: low-alloy steel; structure; chemical composition; mechanical properties; regression model; properties forecast

Features of annealing of alloy steels with mixed structure

It is necessary to obtain initial rolled product with a structure which has high ductility and low hardness for further mechanical processing of alloyed rolled metal products into the ready product. In this case the enterprises carry out a special softening heat treatment to increase the ductility of the metal. The treatment represents the annealing at subcritical temperatures (А1 — 25…40 °С) with long holding. During annealing the structural transformations are running and the formed structure has a granular morphology. To obtain spheroidizing in the steels with a mixed structure (contains at the same time pearlite, bainite or martensite) usually requires a lot of time and energy, because the structural transformations during heat treatment are running with different intensities in different phases. Established by study, that in the steels with a mixed structure during annealing the structural transformations begin from the thermodynamically less stable structures. So, to reduce the mode of the softening heat treatment (annealing) of the investigated steels it is rationally to change the cooling conditions after rolling and to provide the increased quantity of bainite and martensite. For medium-carbon steels alloyed by chromium, molybdenum and vanadium and also for low-carbon steel alloyed by manganese and silicon, an increase of the cooling rate after hot rolling by ~1.5 times allows to obtain more sensitive structure to annealing. So, the structure consists at least 80 % of the bainite, ~15 % of the ferrite and 5 % of the pearlite for chromium-molybdenum steel. The base of the structure contains bainite (~90 %), martensite (~5 %) and ferrite (up to 5 %) for chromium-molybdenum-vanadium steel. For low-carbon silicon-manganese steel an increase of the cooling rate leads to the formation of the structure which contains at least 35 % of the bainite-martensite, ~60 % of the ferrite and 5 % of the pearlite. The structural transformations proceed at the low temperatures and require a shorter duration of the holding in the obtained structures during further annealing. Receiving such structure after rolling, allows to speed up intermediate softening heat treatment, thereby reducing energy costs, and provides high ductility of steel before mechanical processing.

Simulation of Process Rolling Plates from Alloy of Al-Mg System Economically Doped with Scandium

The modes of hot and cold rolling of plates from an alloy of the Al-Mg system alloy, doped with scandium in the range of 0.10-0.12%, are modeled. At the first stage of work, using the DEFORM-3D software package, we simulated the process of hot sheet rolling at the Quarto 2800 mill, in order to obtain a billet for further cold rolling. Analysis of the simulation data showed that with the adopted compression mode, the metal forming and temperature conditions of rolling make it possible to obtain plates up to 45 mm thick, without defects, with rational power loading of the equipment. Further modeling of the regime of cold rolling of plates with a thickness of up to 31.5 mm showed that cold rolling can be carried out in 4 passes, provided that the stress and rolling force do not exceed the permissible values. At the second stage of work, we conducted an experimental verification of the obtained simulation results both in industrial and in laboratory conditions. It was found that the value of the total compression leading to the destruction of the samples, depending on the rolling conditions, should not exceed 21-30%. At this degree of deformation, the rolled metal from the alloy under study has high strength and plastic properties. Subsequent industrial verification of the research results confirmed that this alloy is quite advanced technologically, while it has high deformability, both during hot and cold rolling, which allows us to recommend it for sheet deformed semi-finished products in the manufacture of structural products for various purposes.

The Effect of Boron, Manganese and Sulfur on the Microstructure and Mechanical Properties of Pipe Steel 17G1SU

The paper presents the results of the effect of boron, manganese and sulfur on the microstructure and mechanical properties of pipe steel 17G1SU. It was shown that the microstructure of boron-free steel sample containing 1.4% Mn and 0.01% S consists mainly of ferrite and a small amount of perlite. Samples microalloyed by boron are represented by a dispersed ferritic-bainitic structure. A decrease in ferrite grain size from 8.7 μm, in a comparative sample without boron containing 1.4% Mn and 0.010% S to 5.8 μm in a sample of steel containing 0.006% B, 1.6% Mn and 0.011% S, shows increasing the dispersity of the ferritic-bainitic structure. A decrease in the manganese content to 1.4, sulfur to 0.004% and an increase in boron concentration to 0.0011%, despite an increase in grain size to 6.8 μm, retain a fine-grained structure. The effect of boron, manganese, and sulfur content on the microhardness of the structural phases of the studied pipe steel samples is noted. The smallest microhardness of ferrite and perlite is observed in the base sample without boron, reaching 180 and 214 HV10, respectively. The microalloying of pipe steel containing 1.6% Mn, 0.011% S with boron is accompanied by an increase in the microhardness of the bainitic phase to 314 HV10, which increases to 400 HV10 with an increase in boron concentration to 0.011%, and a decrease in the content of manganese and sulfur to 1.4 and 0.003%. In this case, the microhardness of the ferrite phase, reaching an increase to 260 HV10, is practically independent of the content of boron, manganese, and sulfur. The mechanical properties of the experimental metal rolling with a thickness of 10 mm provide the production of rolled steel of strength class X80, without heat treatment, regardless of the content of boron, manganese, and sulfur, as a result of the formation of a finely dispersed ferrite-bainitic structure.

MODERNIZATION OF LABORATORY ROLLING MILL 150 FOR THE FORMATION OF STUDENTS 'STUDIES OF AUTOMATION OBJECT RESEARCH.

It was fulfilled laboratory rolling mill 150 reconstruction for student’s investigation of rolling mill as automation object. For remote control screw down movement was mounted screw down auxiliary reductor with AC motor, screw down encoder, load cells, inverter with built-in PLC MS-300 and touch panel HMI DOP-103BQ. It was developed PLC and touch panel HMI software for control screw down movement. Software touch panel HMI provide with set point adjustment screw down movement and actual distance monitoring. Software inverter with built-in PLC MS-300 exercise control screw down movement and stopping in position set point without rundown. It was developed software for investigation of rolling force and electrical data’s of mill motor. Software provides measurement and memory of data’s and on-line graphic display. Measurement of rolling force and rolled metal thickness provides ability to build stand stiffness and rolled metal stiffness.

Problems of application of standards in evaluation of microstructure of metals and alloys

The purpose of this work is to consider the problems of applying some standards containing reference scales of structures: 1763-68, 1778-70, 5640-68, 9391-80, 10 243-75, 13938.13-93, 22 838-77, 3443-87 (materials: oxygenated copper, pipe and structural steels, cast iron). It is shown that the normative base of standards for metallographic analysis is morally outdated. The main problem is the discrepancy between the increase in standards and real modern structures. Basically, microstructure standards use a magnification of 100 times, in particular, for the analysis of oxygenated copper, banding of the rolled metal structure, Widmanstätt structure, phosphide eutectic. The analysis of modern materials requires an increase of about 500...800 times. The magnification of 360…400 times, used in some scales, is also insufficient, in particular, for the analysis of structurally free cementite. Also, the quality of images of structures makes them difficult to use. A common disadvantage of the considered standard scales of structures is the absence of metrics in photographs, which does not correspond to the modern level of metallurgy and causes certain inconveniences when comparing structures. It is necessary to revise the standards governing the structure of metals and alloys. Research should be carried out to develop a new generation of standards based on the real structures of modern industrial alloys. It is also necessary to develop new methods of structure analysis. This applies primarily to analysis in image processing programs.

Research on micro riblets rolling process based on uncertainty analysis

The research on micro-riblets has always been a hot spot in the field of passive drag reduction. In many manufacturing processes of metal microstructures, roll forming can maintain the integrity of the metal streamlines and obtain residual compressive stress, which can resist the fatigue damage caused by the metal gap. In the process of manufacturing micro-grooves on rolling metal surface, there are inherent uncertainties in various parameters that result in the uncertainty of product formation and that affect the reliability of the micro-groove quality. Therefore, it is of great significance to study the interaction between the forming height (HZ) and the forming pressure (FZ) due to the uncertainty of the parameters. In this research, the micro-riblet structures HZ and FZ during the micro-groove forming process were used as the inspection indicators, and the multi-pass rolling process was optimized with the response surface method (RSM). A simulation method of the micro-groove rolling process with uncertainty was proposed, and a random convergence model based on samples was established. Through the uncertainty analysis, the reduction, workpiece thickness, friction coefficient, rolling speed, and roller diameter were selected as input parameters. The influence of the uncertainty of several process parameters on the molding height and the pressure was studied. The results showed that the roll reduction had a significant effect on the forming height and the pressure in the Z-direction, while the roller diameter only had a significant effect on the rolling force in the Z-direction.

Development of a convolutional layer of a deep neural network for detecting defects in rolled metal

Development of a convolutional layer of a deep neural network for detecting defects in rolled metal

Синтез регулятора для нелинейных объектов с запаздыванием методом разделения движений с применением критериев устойчивости

Controllers and feedback are applied for performing many technical tasks, for example, maintaining the desired temperature stabilization in the thermostat and speed electric motor stabilization. Different methods such as the time-scale separation method, the frequency-response design method, and the Ziegler–Nichols method are applied to design controllers. The Ziegler–Nichols method does not provide the required transient process quality. The Smith predictor is sometimes applied to control objects with a transport delay. However, it may be difficult to apply the Smith predictor when a mathematical model is not fully known. There is a paper where the application of the motion separation method with a delay is considered. However, the calculation method proposed in that work requires solving a system of four nonlinear equations for a second-order object. Therefore, in this paper, we investigate the possibility of a simpler method for calculating the controller, namely, the possibility of using the Mikhailov criterion in the synthesis of a controller by the motion separation method for nonlinear objects with a delay. Also, the application of the Nyquist stability criterion with a simpler than the proposed earlier calculation procedure is considered in the paper. The values of the regulator coefficients obtained using the Nyquist criterion and the Mikhailov criterion are compared. The Mikhailov criterion and the Nyquist criterion are applied to estimate the stability of the fast motions subsystem. The derivation of formulas to calculate the parameters of the controller designed by the motion separation method for first-order non-linear objects with transport delays and second-order non-linear objects with transport delays with the use of the Mikhailov criterion is also considered in the paper. Transient processes are studied by numerical simulation. Transient processes plots are also given. The parameters of the controller that are needed to improve the performance of transient processes in the presence of a delay are found. The Peltier element, an aircraft strength test stand, a thermostat, and equipment for metal rolling are non-linear control objects with a transport delay. The Mikhailov hodographs for objects with a transport delay are presented.

Surface texture transfer in skin-pass rolling with the effect of roll surface wear

This paper presents a novel three-dimensional characterisation of the wear effects of a roll surface on the texture transfer in skin-pass rolling. The method integrates the interactions of the microscale elastic deformation of roll surface asperities with the microscale plastic deformation of strip surface asperities. An elasticity theory and a discrete fast Fourier transform were used to rationally predict the microscale elastic deformation of work roll in the rolling system. The microscale plastic deformation of the asperities on the soft strip surface was calculated by the material redistribution process. The Archard wear law was used to consider the wear effects with the random contact pressure, relative sliding and surface hardness. A multiscale analysis was carried out by the dynamic explicit finite element method (FEM), which fully coupled microscale surface contacts, macroscale elastic deformation of the work roll and the bulk plastic deformation of the metal strip. Due to the complexity associated with numerical simulation, a novel modularised approach was established to complete the calculation in a feasible and efficient manner. The study reveals that the roughness scale of a rolled metal strip decreases gradually due to the roll surface wear and that the rolling force, relative sliding and rolling speed at the roll-strip interface significantly affect the roll surface wear. It is expected that the method established can be used to control the surface texture transfer in skin-pass rolling under the continuous wear of roll surfaces.

Development of modes for straightening of hot-rolled strip in order to obtain rolled products for high-tech processing

Modern requirements for the quality indicators of hot rolled sheet steel are associated with maintaining high flatness of sheet metal during further processing by high-tech methods, for example, by laser or plasma cutting. When laser cutting a sheet it may bend due to the release of residual stresses that are unevenly distributed over the volume. The final stage in the production of hot rolled steel is straightening on roller straightening machines under cyclic alternating deformation. The solution to the problem is the optimal control of residual stresses at the main final stage of hot rolled sheet production when straightening strips on roller levelers under cyclic alternating deformation. The existing numerous approaches of calculating the parameters of the straightening on roller straightening machines do not allow determining the optimal modes that eliminate the initial inhomogeneous stress state of the hot rolled strip and ensure the minimum level of residual stresses in the rolled product. The paper substantiates the relevance of developing a methodology for selecting a strip straightening mode, which provides an expansion of the possibilities of the straightening process on roller straightening machines and obtaining hot rolled sheets with a minimum level of residual stresses and potential energy, suitable for plasma and laser cutting. The article describes the implementation of the method for selecting the mode of hot rolled strip straightening process based on the results of finite element modeling, confi rmed by experimental data obtained during leveling and subsequent cutting of sheets. The modes of straightening of strips with a thickness of 4 mm, 8 mm and 10 mm of steel grade S355MC have been calculated on 13-, 15- and 17-roller straightening machines of Severstal, providing minimum residual stresses, potential energy in sheets after straightening and deviations from the flatness of sheets during high-tech cutting. Based on industrial tests, the method for calculating straightening modes was introduced into production, the developed modes were accepted for use at Severstal. The proposed improvements of technology of the production of hot rolled sheet metal in the conditions of Severstal made it possible to obtain products suitable for laser cutting.

EFFECT OF DIFFERENT STRAIN ROUTES ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF COPPER

In the current paper, the role of change in strain routes was investigated, along with the cold rolling of copper metal. Four different strain routes including, (a) unidirectional rolling, (b) reverse rolling, (C) two-stage cross-rolling, and (d) multi-stage cross-rolling, were utilized to investigate the effect of strain routes change on microstructure, texture evolution, and anisotropy. Tensile strength in the unidirectional rolling sample compared to the cross-rolling sample decreased in the direction of initial rolling from 364 Mpa to 340 Mpa, in the direction of 45˚ to the initial rolling from 359 Mpa to 347 Mpa, and in the direction of perpendicular to the initial rolling from 371 Mpa to 360 Mpa. Texture intensity also decreased from 1413 in the unidirectional rolling sample to 992 in the cross-rolled sample. The results demonstrated that by rolling in different routes, the cross-rolling has led to a more homogeneous microstructure, less anisotropy, and weaker texture.

ТЕОРЕТИЧЕСКИЕ И ПРАКТИЧЕСКИЕ ОСНОВЫ ПРОКАТНЫХ ИЗДЕЛИЙ

The article presents the theoretical and practical basis for the production of rolled products in the conditions of a metallurgical plant. The processes of plastic deformation of bodies between rotating drive rolls are shown. The main results of research on rolled products made of rolled steel are presented. The chemical composition, mechanical properties, macro -and microstructure parameters, and strengthening treatments of locally produced rolled steel were studied. It is shown that after hardening treatment, the strength increases and the quality of rolled products improves.Keywords:composition and properties of rolled metal products, plastic deformation process, rotating drive rollers, rolled body, rolled steel, hardening heat treatment, hardness, macro-and microstructure, performance and quality of finished products

THE INFLUENCE OF RESONANCE ON THE DEFORMATION OF THE TOOTHS OF BUNDLED CUTTING SAWS

The process of the occurrence of resonance when cutting with a saw to cut metal rolling is considered, the forced and free vibrations of the saw of batch cutting are calculated.

INVESTIGATION OF GEOMETRIC PARAMETERS OF BURRS ON THE PIPE END DURING BATCH CUTTING OF COLD ROLLED METAL

This publication discusses the issue related to the study of geometric parameters of burrs on the end of the pipe during batch cutting of cold rolled metal with disk saws.