Vol. 26 No. 4 2024 3 EDITORIAL COUNCIL EDITORIAL BOARD EDITOR-IN-CHIEF: Anatoliy A. Bataev, D.Sc. (Engineering), Professor, Rector, Novosibirsk State Technical University, Novosibirsk, Russian Federation DEPUTIES EDITOR-IN-CHIEF: Vladimir V. Ivancivsky, D.Sc. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Vadim Y. Skeeba, Ph.D. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Editor of the English translation: Elena A. Lozhkina, Ph.D. (Engineering), Department of Material Science in Mechanical Engineering, Novosibirsk State Technical University, Novosibirsk, Russian Federation The journal is issued since 1999 Publication frequency – 4 numbers a year Data on the journal are published in «Ulrich's Periodical Directory» Journal “Obrabotka Metallov” (“Metal Working and Material Science”) has been Indexed in Clarivate Analytics Services. Novosibirsk State Technical University, Prospekt K. Marksa, 20, Novosibirsk, 630073, Russia Tel.: +7 (383) 346-17-75 http://journals.nstu.ru/obrabotka_metallov E-mail: metal_working@mail.ru; metal_working@corp.nstu.ru Journal “Obrabotka Metallov – Metal Working and Material Science” is indexed in the world's largest abstracting bibliographic and scientometric databases Web of Science and Scopus. Journal “Obrabotka Metallov” (“Metal Working & Material Science”) has entered into an electronic licensing relationship with EBSCO Publishing, the world's leading aggregator of full text journals, magazines and eBooks. The full text of JOURNAL can be found in the EBSCOhost™ databases.
OBRABOTKAMETALLOV Vol. 26 No. 4 2024 4 EDITORIAL COUNCIL EDITORIAL COUNCIL CHAIRMAN: Nikolai V. Pustovoy, D.Sc. (Engineering), Professor, President, Novosibirsk State Technical University, Novosibirsk, Russian Federation MEMBERS: The Federative Republic of Brazil: Alberto Moreira Jorge Junior, Dr.-Ing., Full Professor; Federal University of São Carlos, São Carlos The Federal Republic of Germany: Moniko Greif, Dr.-Ing., Professor, Hochschule RheinMain University of Applied Sciences, Russelsheim Florian Nürnberger, Dr.-Ing., Chief Engineer and Head of the Department “Technology of Materials”, Leibniz Universität Hannover, Garbsen; Thomas Hassel, Dr.-Ing., Head of Underwater Technology Center Hanover, Leibniz Universität Hannover, Garbsen The Spain: Andrey L. Chuvilin, Ph.D. (Physics and Mathematics), Ikerbasque Research Professor, Head of Electron Microscopy Laboratory “CIC nanoGUNE”, San Sebastian The Republic of Belarus: Fyodor I. Panteleenko, D.Sc. (Engineering), Professor, First Vice-Rector, Corresponding Member of National Academy of Sciences of Belarus, Belarusian National Technical University, Minsk The Ukraine: Sergiy V. Kovalevskyy, D.Sc. (Engineering), Professor, Vice Rector for Research and Academic Aff airs, Donbass State Engineering Academy, Kramatorsk The Russian Federation: Vladimir G. Atapin, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Victor P. Balkov, Deputy general director, Research and Development Tooling Institute “VNIIINSTRUMENT”, Moscow; Vladimir A. Bataev, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Vladimir G. Burov, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Aleksandr N. Korotkov, D.Sc. (Engineering), Professor, Kuzbass State Technical University, Kemerovo; Dmitry V. Lobanov, D.Sc. (Engineering), Associate Professor, I.N. Ulianov Chuvash State University, Cheboksary; Aleksey V. Makarov, D.Sc. (Engineering), Corresponding Member of RAS, Head of division, Head of laboratory (Laboratory of Mechanical Properties) M.N. Miheev Institute of Metal Physics, Russian Academy of Sciences (Ural Branch), Yekaterinburg; Aleksandr G. Ovcharenko, D.Sc. (Engineering), Professor, Biysk Technological Institute, Biysk; Yuriy N. Saraev, D.Sc. (Engineering), Professor, V.P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of the RAS, Yakutsk; Alexander S. Yanyushkin, D.Sc. (Engineering), Professor, I.N. Ulianov Chuvash State University, Cheboksary
Vol. 26 No. 4 2024 5 CONTENTS OBRABOTKAMETALLOV TECHNOLOGY Manikanta J.E., Ambhore N., Shamkuwar S., Gurajala N.K., Dakarapu S.R. Investigation of vegetable-based hybrid nanofl uids on machining performance in MQL turning........................................................................................... 6 Dama Y.B., Jogi B.F., Pawade R., Kulkarni A.P. Impact of print orientation on wear behavior in FDM printed PLA Biomaterial: Study for hip-joint implant...................................................................................................................... 19 GrinenkoA.V., ChumaevskyA.V., Sidorov E.A., Utyaganova V.R.,AmirovA.I., Kolubaev E.A. Geometry distortion, edge oxidation, structural changes and cut surface morphology of 100mm thick sheet product made of aluminum, copper and titanium alloys during reverse polarity plasma cutting...................................................................................... 41 Somatkar A., Dwivedi R., Chinchanikar S. Comparative evaluation of roller burnishing of Al6061-T6 alloy under dry and nanofl uid minimum quantity lubrication conditions............................................................................................... 57 Karlina Yu.I., Konyukhov V.Yu., Oparina T.A. Assessment of the quality and mechanical properties of metal layers from low-carbon steel obtained by the WAAM method with the use of additional using additional mechanical and ultrasonic processing..................................................................................................................................................... 75 EQUIPMENT. INSTRUMENTS Yusubov N.D., Abbasova H.M. Systematics of multi-tool setup on lathe group machines............................................... 92 Toshov J.B., Fozilov D.M., Yelemessov K.K., Ruziev U.N., Abdullayev D.N., Baskanbayeva D.D., Bekirova L.R. Increasing the durability of drill bit teeth by changing its manufacturing technology......................................................... 112 Pospelov I.D. Investigation of the distribution of normal contact stresses in deformation zone during hot rolling of strips made of structural low-alloy steels to increase the resistance of working rolls..................................................... 125 Ablyaz T.R., Blokhin V.B., Shlykov E.S., Muratov K.R., Osinnikov I.V. Manufacturing of tool electrodes with optimized confi guration for copy-piercing electrical discharge machining by rapid prototyping method.......................... 138 MATERIAL SCIENCE Shubert A.V., Konovalov S.V., Panchenko I.A. A review of research on high-entropy alloys, its properties, methods of creation and application.................................................................................................................................................. 153 Syusyuka E.N., Amineva E.H., Kabirov Yu.V., Prutsakova N.V. Analysis of changes in the microstructure of compression rings of an auxiliary marine engine.......................................................................................................... 180 Dudareva A.A., Bushueva E.G., Tyurin A.G., Domarov E.V., Nasennik I.E., Shikalov V.S., Skorokhod K.A., Legkodymov A.A. The eff ect of hot plastic deformation on the structure and properties of surface-modifi ed layers after non-vacuum electron beam surfacing of a powder mixture of composition 10Cr-30B on steel 0.12 C-18 Cr-9 Ni-Ti............................................................................................................................................................................. 192 Boltrushevich A.E., Martyushev N.V., Kozlov V.N., Kuznetsova Yu.S. Structure of Inconel 625 alloy blanks obtained by electric arc surfacing and electron beam surfacing........................................................................................... 206 Sablina T.Y., Panchenko M.Yu., Zyatikov I.A., Puchikin A.V., Konovalov I.N., Panchenko Yu.N. Study of surface hydrophilicity of metallic materials modifi ed by ultraviolet laser radiation........................................................................ 218 EDITORIALMATERIALS 234 FOUNDERS MATERIALS 243 CONTENTS
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 4 4 Investigation of the distribution of normal contact stresses in deformation zone during hot rolling of strips made of structural low-alloy steels to increase the resistance of working rolls Ivan Pospelov a,* Cherepovets State University, 5 Lunacharskogo pr., Cherepovets, 162600, Russian Federation a https://orcid.org/0009-0000-5974-5718, idpospelov@chsu.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2024 vol. 26 no. 4 pp. 125–137 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2024-26.4-125-137 ART I CLE I NFO Article history: Received: 23 August 2024 Revised: 16 September 2024 Accepted: 02 October 2024 Available online: 15 December 2024 Keywords: Normal contact stresses Structural low-alloy steels Deformation zone Elastic modulus of the strip Contact strength of working rolls Acknowledgements Some of the research was carried out in the operating conditions of PJSC Severstal. ABSTRACT Introduction. During the operation of the working rolls of the fi nishing groups of continuous wide-strip hot rolling mills, normal contact stresses have a decisive infl uence on its resistance and strength, especially when rolling a range of low-alloy structural steels with a minimum thickness range of 5.5–2.0 mm, which does not correspond to the passport characteristics of such mills. The subject of the study. Previously performed studies of the stress-strain state of the rolled strip in the deformation zones make it possible to estimate the level of normal contact stresses acting on the working rolls during hot rolling of strips of low-carbon steels. The paper discusses the results of the study of the stressed state of strips of low-alloy structural steels in contact with rolls, taking into account the features of the chemical composition of the metal and changes in its elastic properties during deformation at hot rolling temperatures. The results obtained are applicable to the evaluation of the contact strength of the fi nishing rolls of the rolling mill. The purpose of the work is to investigate the distribution of normal contact stresses in the deformation zones during hot rolling of strips of low-alloy structural steels to ensure high resistance of the working rolls. Material and methods. The study is based on the elastic-plastic model and equations for calculating normal contact stresses for each section of the deformation zone. The specifi city of variation of Young’s modulus (modulus of elasticity) of low-alloyed structural steels in accordance with certain hot rolling temperatures is studied in detail, and the contact strength of high-chromium cast iron work rolls is evaluated. Results and discussion. A reliable regression equation is obtained for determining the values of the Young’s modulus of the rolled strip as a function of changing hot rolling temperatures. The results of a numerical experiment are presented in the form of calculating the maximum normal contact stresses using the elastic-plastic model of the deformation zone and assessing the contact strength of the work rolls based on actual rolling conditions on an operating mill. New improved technological modes of hot rolling of low-alloy structural steels (0.1 C-Cr-Si-Ni-Cu, 0.18 C-Cr-Mn-Ti and 0.14 C-2 Mn-N-V) are proposed, which make it possible to reduce the maximum contact stresses and increase the resistance of the working rolls. For citation: Pospelov I.D. Investigation of the distribution of normal contact stresses in deformation zone during hot rolling of strips made of structural low-alloy steels to increase the resistance of working rolls. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2024, vol. 26, no. 4, pp. 125–137. DOI: 10.17212/1994-6309-2024-26.4-125-137. (In Russian). ______ * Corresponding author Pospelov Ivan D., Ph.D. (Engineering), Associate Professor Cherepovets State University, 5 Lunacharskogo pr., 162600, Cherepovets, Russian Federation Tel.: +7 963 353-53-71, e-mail: idpospelov@chsu.ru Introduction The priority task of the development of modern fl at rolled products manufacturing is to develop the technology for hot rolled strip production from structural low-alloyed steels for welded structures with the thickness range of 5.5 to 2.0 mm. Simultaneously with complication of assortment, not corresponding to passport characteristics of continuous wide-strip hot rolling mills and increase of requirements for equipment performance, it is essential to reduce specifi c consumption of working rolls and increase its lifetime, since the cost of rolls in the expense structure of the rolling production reaches 15–20 % [1].
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 4 2024 The possibility of increasing the lifetime of operated working rolls of hot rolling mills is provided in some studies [2–9] related to direct infl uence of hot rolling process temperature on the stresses occurring in rolls. However, the materials of the above-presented works practically do not take into account specifi c features of stress-strain state during strip contact with working rolls [10–12].At the same time, application of calculation methods for such a stress-strain state based on the elastic-plastic model of the deformation zone [10–12] demonstrated that the calculations require some clarifi cation. The materials of the publication [13] reveal the infl uence of diff erent ranges of hot rolling temperatures and actual steel chemical compositions with carbon content less than 0.25 % on elastic and plastic properties of strips deformed in the mill. A conclusion is made in the same paper [13] that the length of elastic sections can reach 32 to 40 % of the total length of the deformation zone; this feature was not previously taken into account. The described changes in the structure of deformation zones when producing rolled products from structural low-alloyed steels with the minimal thickness range of 5.5 to 2.0 mm result in the problem of shortening lifetime of working rolls in last stands of continuous wide-strip hot rolling mills because of increased normal contact stresses in the deformation zone, as further calculations showed, to the dangerous level of 1,068 to 1,245 MPa, typical for cold rolling mills [10]. An eff ective solution to the problem of increasing the lifetime of operated working rolls at the stage of development hot rolling process modes at modern steel plants should begin with reliable methods for calculating the energy-force parameters and stress-strain state of the strip in the contact with working rolls [11–13]. The purpose of the work is to study the distribution of normal contact stresses in deformation zones during hot rolling of strips from low-alloyed structural steels to achieve high lifetime of working rolls. The research objectives are to supplement the method of calculation of normal contact stresses in production of low-alloyed structural carbon steels; to construct a linear regression within the elasticity modulus calculation; to study distribution of normal contact stresses in deformation zones during hot rolling considering special features of its stress-strain state on the basis of the existing process mode; to improve the technology of hot rolled strips production from low-alloyed structural steels in the fi nishing train of the wide-strip mill to achieve high lifetime of work rolls; to evaluate the effi ciency of the developed procedure and new hot rolling modes. Research methods Based on the modelling of the stress-strain state of the strip during hot rolling [11–13], Table 1 provides formulas for calculating рх(hх) for elastic and plastic sections of the deformation zone. The lengths of such sections are indicated as х1, х4 and х2, х3 respectively. The formulas help to study and reveal the regularities of changes in the maximum normal contact stresses р1max, p4max and pxmax, distributed along the length of the deformation zone lc in Fig. 1. Table 1 shows that the calculation of normal contact stresses px(hx) of strip hot rolling, with known values of reduction in thickness Δhi = hi−1 − hi and specifi c interstand tensions σi−1 and σi, directly depends on the correct defi nition of the elasticity modulus ЕS, the friction factor in the deformation zone μi and the actual plastic resistance σpl. The specifi cs of μi and σpl values determination depending on deformation-velocity parameters, working rolls material and chemical composition of hot rolled steel are given in [12–14]. Varying strip elasticity modulus ЕS at the temperature of 1,050 to 750 °С, which is typical for fi nishing stands of hot rolling mills, is of particular interest for the study of structural low-carbon steel rolling. For steels 0.14 C-2 Mn-N-V, 0.18 C-Cr-Mn-Ti and 0.1 C-Cr-Si-Ni-Cu, selected for further calculations of normal contact stresses during rolling and for evaluation of lifetime of working rolls in the fi nishing train of continuous wide-strip Mill 2000 at PAO Severstal, the dependence of ЕS on temperature, according to reference data [15], has the form shown in Fig. 2. Standard calculation methods intended for all machine parts were used to evaluate the rolls contact strength during rolling. The correction was performed using the formula of allowable stresses for the compression scheme from [16] to apply these conventional methods to cast iron rolls of rolling mills: [ ] 1.5 , u σ = ⋅ σ (1) where σu is the ultimate compressive strength of the working roll material, MPa.
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 4 4 Ta b l e 1 Formulas for calculating normal contact stresses px(hx) The fi rst elastic section with a length of х1 The second elastic section with a length of х4 1 1 1 1 2 1.15 1 x x S i i i h p E h − − − ⎧ ⎛ ⎞ ⎪ = ⋅ ⋅ − ⋅ + ⎨ ⎜ ⎟ δ δ + ⎪ ⎝ ⎠ ⎩ ( ) 1 1 1 1 1 1 1 1 1.15 i i i i x i i S h h E − δ − − − − − ⎫ ⎡ ⎤ ⎛ ⎞ δ − σ ⎪ + − ⎢ ⎥⎬ ⎜ ⎟ δ + ⋅ δ ⋅ ⎢ ⎥ ⎝ ⎠ ⎪ ⎣ ⎦⎭ , where 1 tg 2 i i − μ δ = ⎛ α ⎞ ⎜ ⎟ ⎝ ⎠ 1 2 1.15 1 x x S i i i h p E h ⎧ ⎛ ⎞ ⎪ = ⋅ ⋅ − ⋅ + ⎨ ⎜ ⎟ δ δ + ⎪ ⎝ ⎠ ⎩ 1 ( 1) 1.15 i i i i x i i S h h E δ ⎫ ⎛ ⎞ ⎡ ⎤ δ − σ ⎪ + − ⎬ ⎜ ⎟ ⎢ ⎥ δ + ⋅ δ ⋅ ⎪ ⎝ ⎠ ⎣ ⎦⎭ , where ( ) tg i i μ δ = β Plastic section ( ) ( ) 1 1 1 1 1 ( ) 0.5 0.5 1.15 1 ln( ) ln( ) ( ) 1.15 tg tg 2 2 x n x pl x n n pl h h h p p h h h h h h ⎡ ⎤ ⎛ ⎞ ⎢ ⎥ ⎜ ⎟ − ⎢ ⎥ ⎜ ⎟ = ⋅ σ ⋅ ⋅ + + ⋅ + − + ⎢ α α ⎥ − ⎜ − ⎟ ⋅ σ ⎛ ⎞ ⎛ ⎞ ⎜ ⎟ ⎜ ⎟ ⎢ ⎥ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎣ ⎦ Fig. 1. Distribution pattern of normal contact stresses in the deformation zone during hot rolling: 1 – deformable strip; 2 – working roll; hi−1, hi – thickness of the strip before and after rolling, mm; h1, h4 – thickness of the strip at the boundaries of the fi rst and second elastic sections, mm; hn – thickness in neutral section, mm; x1, x4 – lengths of elastic sections, mm; x2, x3 – lengths of the plastic sections of lag and advance, mm; τi – contact tangential stresses, MPa; рi – normal contact stresses, MPa; α – angle of nip of the strip, β – angle of inclination of the deformation zone on the second elastic section, deg; σi-1, σi – back and front tensions, MPa
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 4 2024 Fig. 2. Change in the modulus of elasticity of low-alloy structural steels depending on the test temperature Results and discussion In order to use data shown in Fig. 2 in further calculations of contact stresses in deformation zones, the linear approximation of the elasticity modulus (Young’s modulus) ЕS dependence on temperature was performed for hot rolling of strips and equation (2) was obtained with the determination coeffi cient R2 = 0.9869 and the calculated value of the Fisher criterion (F-test). The F-test value is greater than that from the table, so the linear regression equation given below is signifi cant and gives an accurate and reliable prediction. 2.1778 0.0011 , S i E t = − ⋅ (2) where ti is the temperature of the rolled strip in the i-th mill stand, °С. The actual process mode for rolling a strip from 0.1 C-Cr-Si-Ni-Cu steel with the thickness of 2.1 mm and the width of 1,270 mm in the fi nishing seven-stand train of Mill 2000 of PAO Severstal in stands No.7, No.9 and No.11 respectively, more utilized during hot rolling, was used to study the distribution of normal contact stresses after a strip contact with working rolls. The above-mentioned features of hot rolling of low-alloyed structural steels and calculation formulas from Table 1 were used to study stresses. The target chemical composition of the specifi ed steel grade, its rolling process mode, structural parameters of deformation zones and calculated values of normal contact stresses in the above-mentioned stands are provided in Table 2. The Fig. 3 schematically represents the distribution of maximum normal stresses on the plastic section in stands No.7, No.9 and No.11 during strip hot rolling according to the mode specifi ed in Table 2. This plastic section completely consists of the stick area [11–13]. The estimated values from Table 2 and Table 3 demonstrate that maximum values of contact stresses pxmax infl uence the plastic section of the deformation zone in the lag section with the length of х2 (Fig. 1) near the neutral section, also one can see slight decrease of such stresses to maximum values р4maх on the border of the plastic and second elastic section. Taking into account the above, when determining the stress-strain state of the strip in the contact with working rolls, particularly when calculating х4 and р4maх, it is necessary to take into account the peculiarity of the change in the modulus of elasticity of the steel in Fig. 2. Calculation using formula (1), taking into account the tests of the ultimate strength of high chromium cast iron working rolls σu = 700–800 MPa [17] used in fi nishing train stands of Mill 2000, indicates that permissible contact stresses are in the range of [σ] = 1,050–1,200 MPa. Comparing the maximum normal contact stresses рхmax from Table 2 and the above permissible stresses [σ] we can conclude that these stresses are the most dangerous for the working rolls in stand No.11, because the stresses fall in the range of
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 4 4 permissible values [σ] in several estimated points of the deformation zone рхmax and pnmax (Fig. 3). The fact of the maximum loading of the roll system of the four-high stand No.11 according to the existing production technology in the fi nishing train of the Mill 2000 is also confi rmed by studies in [18]. The risk of further growth of maximum contact stresses рхmax increases signifi cantly during hot rolling of strip sections with higher longitudinal thickness variation due to fl uctuations in the force Рi as a function of all crucial process factors [19, 20], therefore the risks of surface damage, reduced lifetime, or destruction of working rolls and the risk of emergency roll change increase due to repetitive loading and heavy thermal stresses [21–23]. It should also be noted that rolling of low-alloyed structural steels in the conditions of real production of the fi nishing train is performed before scheduled rolls change in all stands of Mill 2000, therefore the calculated values of maximum contact stresses рхmax and pnmax (Fig. 3) really aff ect the working roll lifetime. The studies [19, 20] can be used as a potential for improving the technology of hot-rolled high-strength steel strips production in the fi nishing train of a wide-strip mill to ensure high durability of working rolls. The essence of the proposed improvement in rolling strips of high-strength steels is that the increase of percentage reductions εi in the fi rst three stands of the Mill 2000 fi nishing train in the rolling direction to maximum permissible values of reductions εi.max or Pi.max force, as specifi ed in the mill technical passport data, have no signifi cant impact on growth of maximum normal contact stresses рхmax because of high Ta b l e 2 Chemical composition of 0.1 C-Cr-Si-Ni-Cu steel, rolling process condition and the results of calculating the structural parameters of the deformation zone and normal contact stresses Chemical composition, % С Si Mn Cr Mo Ni Al Cu Nb Ti V 0.102 0.87 0.55 0.63 0.05 0.53 0.016 0.46 0.001 0.003 0.002 Rolling stand No. 7 9 11 Outgoing thickness hi, mm 10.43 3.99 2.33 Percentage reduction εi, % 48.16 34.27 19.09 Back tension σi−1, MPa 20 30 40 Front tension σi, MPa 30 30 40 Rolling speed υi, m/s 2.3 5.76 10.36 Strip temperature ti, oС 1,024 984 939 Coeffi cient of friction μi 0.418 0.295 0.24 Plastic resistance σpl, MPa 167 239.9 315.1 Young’s modulus for work rolls ЕR, MPa 205,000 185,000 185,000 Young’s modulus for a strip ЕS, MPa 105,165 109,497 114,494 Rolling force Рi, MN 33.46 23.13 19.97 Length of deformation zone lc, mm 63.8 29.56 26.76 Elastic section length x4, mm 4.85 6.31 8.18 Maximum normal contact stresses р1max, MPa 172.6 247.1 327.7 Maximum normal contact stresses on the plastic section рхmax, MPa 332.5 645.9 1,067.7 Normal contact stresses in the neutral section рnmax, MPa 328.5 643.3 1,066.9 Maximum normal contact stresses р4max, MPa 190.5 378.9 798.3
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 4 2024 rolling temperature (Table 2). The decrease of reductions and increase of specifi c interstand tensions σi−1 and σi to maximal possible values ≤ 60 MPa, as shown by successful experience of implementation at various hot rolling mills in [19, 20], in the rolling direction in the last stands greatly reduce fl uctuations of forces Рi and strip thickness in it. Table 3 presents the process restrictions, new design modes and values of normal contact stresses in the above-mentioned stands No.7, No.9 and No.11. Table 3 is an illustrative example of the effi ciency of the developed method related to redistributing reductions and increasing interstand tensions in the area of contact stresses decrease during hot rolling of 2.1×1,270 mm strip made of 0.1 C-Cr-Si-Ni-Cu steel. The effi ciency of the initial adjustment of hot rolling process modes for low-alloyed structural steel 0.1 C-Cr-Si-Ni-Cu according to the above principle demonstrates the decrease of maximum normal contact stresses in the stand No.11 and up to the safe range of calculated values рхmax = 837.5–838.0 MPa (Table 3). The lifetime of the working rolls of stand No.7 with the increase of reduction to the maximum value εi.max, as shown by calculation of stresses рхmax (Table 3), does not depend on normal contact stresses from the strip contact with the working roll; the decisive factors of the technology are the high temperature of rolling ti, which greatly aff ects thermal deformations and eff ective cooling of working roll bodies [24]. Similar calculations of the maximum contact stresses рхmax and pnmax were done for steels 0.18 CCr-Mn-Ti and 0.14 C-2 Mn-N-V (Table 4) during hot rolling in stands of the fi nishing train from the thickness of 35.5 mm to the thickness of 2.1 mm, to demonstrate the feasibility of using new improved modes compared to the existing ones to increase contact strength of working rolls. Table 4 shows that hot rolling, according to operating modes, of structural steels 0.18 C-Cr-Mn-Ti and 0.14 C-2 Mn-N-V with higher content of carbon and alloying elements, results in increase ofmaximal contact stresses to the values рхmax = 1,095.7–1,245 MPa, which exceed the permissible values [σ] = 1,200 MPa. The results of calculations given in Table 3 and Table 4 lead us to a conclusion that the algorithm of optimization of hot rolling process modes from [19, 20] can be applied to improve the strip rolling technology to ensure high durability of working rolls by reducing of maximum contact stresses to the range of 838–1,023 MPa. Fig. 3. Distribution pattern of normal contact stresses along the length of the deformation zone in rolling stands No.7, No.9 and No.11
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 4 4 Ta b l e 3 Technological constrains, the new rolling mode and results of normal contact stresses calculation Rolling stand No. 7 9 11 Maximum percentage reduction εi.max, % 50 30 25 Maximum rolling force Рi.max, MN 35 28 20 Maximum back tension σi.max, MPa 22 35 47 Maximum front tension σi.max, MPa 31 42 55 Estimated rolling speed υi, m/s 1.97 6.08 11.41 Design strip temperature ti, oС 1,016 975 935 Estimated percentage reduction εi, % 50 20.45 10 Plastic resistance σpl, MPa 174 247 313 Young’s modulus for a strip ЕS, MPa 105,981 110,479 114,922 Rolling force Рi, MN 33.81 14.93 12.4 Maximum estimated normal contact stresses on the plastic section рхmax, MPa 350.1 634.73 837.5 Estimated normal contact stresses in the neutral section рnmax, MPa 341.7 633.85 838 Ta b l e 4 Operating and new rolling schedule and calculation results of maximum normal contact stresses Steel Rolling mode Rolling stand No. εi, % σi-1/σi, MPa рхmax, MPa рхmax, MPa 0.18 C-Cr-Mn-Ti Operating schedule 7 48.5 20/30 337 329.6 9 34.3 30/30 685 682.5 11 21.3 40/40 1,096.5 1,095.7 New schedule 7 50 24/32 393.5 386 9 30 37/43 664 663 11 18.9 49/58 939 938 0.14 C-2 Mn-N-V Operating schedule 7 47.9 20/30 378 370 9 33.8 30/30 750.2 748 11 22.1 40/0 1,245 1,243.4 New schedule 7 50 30/35 441 433 9 30 40/48 732.6 731 11 19.1 50/60 1,023 1,021.9 Conclusions 1. The method of calculation for normal contact stresses in elastic sections of the deformation zone during rolling of low-alloyed structural carbon steels is supplemented by the dependence of the change in the elasticity modulus of the strips on temperature. 2. A regression equation is obtained for predicting the calculated values of the elasticity modulus of such steels as a function of the change in hot rolling temperature.
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 4 2024 3. A study is carried out of the distribution of normal contact stresses along the length of the deformation zone taking into account the specifi c features of the stress-strain state of the strip contacting with working rolls based on the existing hot rolling process mode in the most utilized stands of the fi nishing train of Mill 2000. According to the study results it is noted that the existing rolling process modes lead to growth of maximum contact stresses in the stand No.11 of the fi nishing train of the hot rolling Mill 2000 of PAO Severstal to dangerous range of values of 1,068–1,245 MPa in the plastic section of the deformation zone. The working rolls resistance to early emergency destruction under conditions of the above stated maximum stresses falling within and exceeding the range of permissible contact stresses [σ] = 1,050–1,200 MPa can be explained by the fact that the material of the working rolls in the contact area is in favourable conditions of all-round elastic compression. 4. Improved modes of reduction and specifi c interstand tensions, which can reduce and maintain maximum normal contact stresses in the stand No.11 of the fi nishing train in a safe range of 838–1,023 MPa, are calculated and suggested based on the previously developed principles of hot rolling process modes optimization to reduce fl uctuations in thickness and force. It is concluded that the developed approach to evaluation of lifetime of work rolls in hot rolling mill fi nishing trains when exposed to normal contact stresses and a new advanced method of the modes initial adjustment can be applied for designing the effi cient rolling technology for low-alloyed structural steels with the minimal thickness range of 5.5–2.0 mm. References 1. Gostev K.A. Optimizatsiya prokatnykh valkov v tselyakh snizheniya sovokupnoi stoimosti vladeniya [Optimization of rolling rolls with the purpose of reducing the TCO]. Stal’ = Steel in Translation, 2021, no. 10, pp. 19–24. (In Russian). 2. Hu K., Zhu F., Chen J., Noda N.-A., Han W., Sano Y. Simulation of thermal stress and fatigue life prediction of high speed steel work roll during hot rolling considering the initial residual stress. Metals, 2019, vol. 9 (9), p. 966. DOI: 10.3390/met9090966. 3. Weidlich F., Braga A.P.V., da Silva Lima L.G., Boccalini G., Souza R.M. The infl uence of rolling mill process parameters on roll thermal fatigue. International Journal of Advanced Manufacturing Technologies, 2019, vol. 102, pp. 2159–2171. DOI: 10.1007/s00170-019-03293-1. 4. Deng G.Y., Zhu Q., Tieu A.K., Zhu H.T., Reid M., Saleh A.A., Su L.H., Ta T.D., Zhang J., Lu C. Evolution of microstructure, temperature and stress in a high speed steel work roll during hot rolling experiment and modeling. Journal of Materials Processing Technology, 2017, vol. 240, pp. 200–208. DOI: 10.1016/j.jmatprotec.2016.09.025. 5. Kiss I., Pinca Bretotean С., Josan А. Experimental research upon the durability in exploitation of the Adamite type rolls. IOP Conference Series: Materials Science and Engineering, 2018, vol. 393 (1), p. 012090. DOI: 10.1088/1757-899X/393/1/012090. 6. Mercado-Solis R.D., Talamantes-Silva J., Beynon J.H., Hernandes-Rodrigues M.A.L. Modelling surface thermal damage to mill rolls. Wear, 2007, vol. 263 (17–20), pp. 1560–1567. DOI: 10.1016/j.wear.2006.12.062. 7. Kotrbacek P., Horsky J., Raudensky M., Pohanka M. Experimental study of heat transfer in hot rolling. Revue de Métallurgie, 2006, vol. 103 (7), pp. 333–341. DOI: 10.1051/metal:2006134. 8. Pinca-Bretotean C., JosanA., Kumar SharmaA. Infl uence of thermal stresses on the phenomenon of thermal fatigue of rolling cylinders. Journal of Physics: Conference Series, 2023, vol. 2540 (1), p. 012023. DOI: 10.1088/17426596/2540/1/012023. 9. Dünckelmeyer M., Krempaszky C., Werner E., Hein G., Schörkhuber K. Analytical modeling of thermo-mechanically induced residual stresses of work rolls during hot rolling. Steel Research International, 2010, vol. 81, pp. 86–89. 10. Garber E.A., Kozhevnikova I.A. Sopostavitel’nyi analiz napryazhenno-deformirovannogo sostoyaniya metalla i energosilovykh parametrov protsessov goryachei i kholodnoi prokatki tonkikh shirokikh polos [Comparative study of stress-strained state of metal and energy-force parameters of hot and cold rolling processes of thin wide strips]. Proizvodstvo prokata = Rolling, 2008, no. 1, pp. 10–15. 11. Garber E.A., Kozhevnikova I.A., Tarasov P.A. Eff ect of sliding and rolling friction on the energy-force parameters during hot rolling in four-high stands. Russian Metallurgy (Metally), 2007, vol. 2007, pp. 484–491. DOI: 10.1134/S0036029507060080.
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 4 4 12. Garber E.A., Kozhevnikova I.A., Tarasov P.A., Zavrazhnov A.A., Traino A.I. Simulation of contact stresses and forces during hot rolling of thin wide strips with allowance for a stick zone and elastic regions in the deformation zone. Russian Metallurgy (Metally), 2007, vol. 2007 (2), pp. 112–119. DOI: 10.1134/S003602950702005X. 13. Garber E.A., Pospelov I.D., Kozhevnikova I.A. Vliyanie khimicheskogo sostava i uprugikh svoistv polosy i valkov na energosilovye parametry shirokopolosnykh stanov goryachei prokatki [Infl uence of practically chemical composition and elastic properties of strip and rolls on calculation accuracy of energy and force parameters in wide strip hot rolling mills]. Proizvodstvo prokata = Rolling, 2011, no. 8, pp. 2–7. 14. Pospelov I.D., Nechaev R.R. Improving the methodology for calculating the fi nishing group power of a continuous wide-strip hot rolling mill. Steel in Translation, 2024, vol. 54 (2), pp. 151–156. DOI: 10.3103/ S0967091224700396. 15. Zubchenko A.S., ed. Marochnik stalei i splavov [Steel and alloy grade guide]. Moscow, Mashinostroenie Publ., 2001. 672 p. ISBN 5-217-02992-7. 16. Gorskii A.I., Ivanov-Emin E.B., Korenovskii A.I. Opredelenie dopuskaemykh napryazhenii pri raschetakh na prochnost’ [Determination of permissible stresses in strength calculations]. Moscow, NIIMash Publ., 1974. 79 p. 17. Lekomt-Bekers Zh., Terziev L., Braier Zh.-P. Ekspluatatsionnye svoistva prokatnykh valkov iz grafi tovogo khromistogo chuguna [Working properties of graphite chrome cast iron rolling rolls]. Stal’ = Steel in Translation, 2000, no. 1, pp. 46–50. (In Russian). 18. Ermushin D.E., Bolobanova N.L. Issledovanie poverkhnostnogo deformatsionnogo uprochneniya bochki opornykh valkov chistovoi gruppy shirokopolosnogo stana goryachei prokatki [Investigation of surface strain hardening of the barrel of back-up rolls in the fi nishing group of a broadband hot rolling mill]. Chernye metally = Stahl und eisen, 2023, no. 2, pp. 27–32. DOI: 10.17580/chm.2023.02.04. (In Russian). 19. Garber E.A., Pospelov I.D., Traino A.I., Savinykh A.F., Nikolaev N.Yu., Mishnev P.A. Simulation of the longitudinal thickness deviation of the steel strips hot rolled in the continuous group of a broad-strip mill. Russian Metallurgy (Metally), 2012, vol. 2012 (9), pp. 831–836. DOI: 10.1134/S0036029512090042. 20. Garber E.A., Pospelov I.D., Savinykh A.F., Nikolaev N.Yu., Mishnev P.A. Optimizatsiya rezhima goryachei prokatki stal’nykh polos na shirokopolosnom stane po kriteriyu «minimum prodol’noi raznotolshchinnosti» [Optimization of hot rolling condition of steel strip on wide-strip mill by «minimum longitudinal crowing» criteria]. Proizvodstvo prokata = Rolling, 2012, no. 5, pp. 15–21. 21. Palit P., Jugade H.R., Jha A.K., Das S., Mukhopadhyay G. Failure analysis of work rolls of a thin hot strip mill. Case Studies in Engineering Failure Analysis, 2015, vol. 3, pp. 39–45. DOI: 10.1016/j.csefa.2015.01.001. 22. Setiawan R., Siradj E., Iman F. Failure analysis of ICDP work roll of hot strip mill: case study of shell-core interface spalling. Jurnal Pendidikan Teknologi Kejuruan, 2022, vol. 5 (1), pp. 28–34. DOI: 10.24036/jptk.v5i1.27023. 23. Salehebrahimnejad B., Doniavi A., Moradi M., Shahbaz M. Investigation of the initial residual stress eff ects on a work roll maximum in-service stress in hot rolling process by a semi-analytical method. Journal of Manufacturing Processes, 2023, vol. 99 (9), pp. 53–64. DOI: 10.1016/j.jmapro.2023.04.084. 24. Garber E.A., Khlopotin M.V., Popov E.S., Savinykh A.F., Golovanov A.V. Povyshenie eff ektivnosti okhlazhdeniya valkov shirokopolosnogo stana goryachei prokatki s ispol’zovaniem adaptivnykh matematicheskikh modelei teplovogo balansa [Improving the effi ciency of cooling rolls in a wide-strip hot rolling mill using adaptive mathematical models of heat balance]. Proizvodstvo prokata = Rolling, 2009, no. 4, pp. 12–24. Confl icts of Interest The author declare no confl ict of interest. © 2024 The Author. Published by Novosibirsk State Technical University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0).
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