Pipe Rolling Research Articles

Investigation of the influence of the frequency of rotation of the rolls on the inhomogeneity of deformation during lengthwise rolling of pipes on a stub mandrel

Abstract The article is devoted to the studying the process of lengthwise rolling of pipes on a stub mandrel. With the use of computer simulation made for material AISI-1045, the effect of rheological properties on the inhomogeneity of deformation is investigated. The study shows that the rolls rotation frequency produces an effect on the wall thickness variation along the pipe perimeter. There is a critical value of the rotation frequency of the rolls of about 115 rpm, at which the greatest difference in wall thickness along the pipe perimeter is observed. The lower or higher values of rotation frequency allow to make the pipe profile more precise. The article gives the practical recommendation to reduce rolls rotation frequency in order to improve the dimensional accuracy of pipes taking into account the effect of local heating of the metal in the deformation zone due to contact friction on the mandrel.

Crossing Axes of Workpiece and Tool at Grinding of the Circular Trough with Variable Profile

Abstract In the article the method of grinding with crossed axes of the tool and the workpiece got further developed. The work discloses a method of processing details having an external surface with a profile in the form of an arc of a circle of variable radius (for example, rolls of pipe rolling mills). The particular three-dimensional geometric models of the processing, shaping and profiling of abrasive wheels have been developed. A method for controlling the grinding process, which ensures the removal of allowances along equidistant curves has been offered. The developed method of grinding provides a constant depth of cutting according to the coordinate of profile processing. This is achieved at the expense of the synchronous inclination of the wheel and its insertion by the size of the allowance. The diameter of grinding wheel affects on the maximum angle of orientation of the wheel has been proven. It has been shown that increasing the diameter of the abrasive wheel has led to a slight decrease in value orientation angle.

Lubrication in Cold Rolling and Drawing of Pipe

The use of lubricant in the cold rolling and drawing of pipe is considered in theoretical and practical terms. Its use proves positive. The transfer of lubricant to the deformation region is analyzed, as well as the influence of the lubricant on the surface microrelief of the pipe. Experimental data and industrial practice are analyzed. Recommendations are made regarding lubricant selection and means of ensuring production efficiency and meeting the requirements on the surface quality of the pipe.

Изучение тепловых явлений при гибке труб с раскатыванием

Изучение тепловых явлений при гибке труб с раскатыванием

Complex study of deformation mode of working stand of pipes cold rolling mill

Elaboration of main concepts of working stands reconstruction, providing an increase of their operation strength and improving of rolled pipes quality and at the same time a decrease of metal intensity is an actual task. Solving of the task will result to a great extent in expanding of technological possibilities and increasing of productivity pipe cold rolling mills.Results of complex study of deformation mode of working stands of pipe cold pilger mills of different designs presented. Influence of working stands parameters both existing and of rational designs on quality of rolled pipes determined. The study determined, that thanks to application of roller installation with ring roll passes and new bearings an expansion of technological possibilities of ХПТ 32 mill reached. Increase of rolled pipes quality was reached by utilization in the drive line of ХПТ 32 mill a modernized working stand of rational design, which has a high operation reliability and an increased rigidity.

Improving the preparation of the liner for rolling on the pilger mill

Purpose. Based on the analysis of the features of the hot piligrim pipe rolling process, develop a new and improved method for preparing liners on the mandrel by compressing their hind ends with specialized strikers of a horizontal hydraulic press. Metodology. The solution to the problem of determining the average specific application on the contact of the liner with the mandrel during compression of its rear end by specialized press dies using the method of slip lines. Findings. The article presents the results of a theoretical determination of the average specific pressure and the width of the contact surface area between the sleeve and the mandrel when the rear end of the sleeve is compressed by specialized strikers of a horizontal hydraulic press. The results obtained allow us to determine the conditions for preventing the liner from slipping from the mandrel as they move toward the rollers in the braking phase. Originality. The main factors affecting the adhesion of the liner to the mandrel were determined, and the values of average specific pressures on the contact of the metal with the mandrel were calculated during the reduction by the profile dies, as well as the width of the contact area and the required thickness of the dies. It has been established that the thickness of the strikers of a double-sided press can be assumed to be the same for all sizes of sleeves of the assortment TPA 5-12 ''. Practical value. The results of the theoretical studies can be used to modernize and reconstruct a section of the off-site charging of a pilger mill TPA 5-12 '' by installing horizontal hydraulic presses with double-die profile dies. This will increase the productivity of the mill by preventing the sleeve from sliding down the mandrel during roll-up to the rolls by creating the necessary adhesion forces between the sleeve and the mandrel. In addition, it will facilitate the conditions of the seed regime piligrim rolling, which will reduce machine time and increase productivity. Key words: pipe, liner, pilgrim mill, hydraulic press, hammer head, mandrel, performance.

Technical Upgrading and Thermal Performance of Heating Furnace of the Pipe Rolling Workshop

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Development of multipass skew rolling technology for stainless steel and alloy pipes’ production

The paper presents the development of new technology and equipment for seamless pipe rolling from hard deformable stainless steels and nickel-base alloys. The research in piercing and elongation of pipes was carried out in the laboratory of the National University of Science and Technology “MISIS” (NUST “MISIS”) and in factory conditions. The study confirmed the possibility of obtaining pipes with high accuracy. Given the research results, a new technology and special equipment for 90–270-mm diameter hot-rolled seamless pipes manufactured from high-alloy steels and alloys was proposed. The technology is based on the processes of two-stage hot piercing in a two roll skew rolling mill with guide shoes and conical mandrel. Elongation in a two roll mill on a long cylindrical mandrel makes it possible to obtain pipes of alloyed steels with ratio of outer diameter to wall thickness up to 27. High quality of pipes with wall variation up to 6% is achieved through the distribution of the coefficient of elongation and the reduction in the operations.

How to be an Exchequer Clerk in the Twelfth Century: What the Dialogue of the Exchequer is Really About

AbstractThe article contributes to the ongoing discussion about the Dialogue of the Exchequer. For quite a long time researchers have been puzzled by the treatise written by the royal treasurer Richard of Ely around the year 1180. It has been regarded as a manual for Exchequer clerks, describing in great detail the workings of Henry II's financial administration. Several of these details, however, have been proven to be wrong or not relevant for the clerks’ work. By comparing the Dialogue with the actual records written during the accounting procedures of the twelfth century – the pipe rolls – and by analysing the Dialogue, I come to the conclusion that the Dialogue did not serve as a guidebook on how to write a pipe roll, but as a guidebook on how to be, and how to think, as an Exchequer clerk.

Parametric study on a novel grouted rolling pipe splice for precast concrete construction

Grout-filled mechanical splice system, with its remarkable ability to connect precast elements, is one of the most important technologies for precast concrete construction. However, for the time being, its high cost has hindered the implementation of precast concrete structures to a certain degree in developing countries. This paper presents a new type of grouted sleeve which can be easily and economically fabricated with a standard seamless steel pipe through cold rolling techniques. Utilizing this sleeve, 69 sets of coupler specimens were prepared considering parameters of inner cavity structure and cross-sectional dimension of sleeve, grout strength, and diameter and embedded length of steel bar. Through direct pullout test, it is shown that the proposed splice is capable of developing of 100% of ultimate strength of the bar providing an embedded length of 6 times bar diameter. Increasing the number and height of inner concentric rib which rolled on the sleeve only in inelastic segment is an effective technique to improve the bond strength of the splice. With the increment of the ribs, clearly different effects of sleeve dimension and grout cylinder thickness on the bond strength can be observed due to different confining mechanism. Finally, a design method for the novel deformed grouted splice sleeve is proposed.

RANCANG BANGUN RASIO GEAR TERHADAP KECEPATAN PENGEROLAN PIPA

The basic principle of metal formation is a process that is done by giving shape changes on the workpiece. This shape change can be done by providing an outer force resulting in plastic deformation. The application of this metal formation can be seen in some examples such as rolling, bending, forging, extruding, wire drawing, deep drawing, and so on. In the process of formation of this metal is also used tooling (bending) whose function gives style to the workpiece, and direct the change of shape. Knowing the speed of the power forwarding system on the pipe roller machine starting from the power source until power is used as the work cycle, and to know the type of belt, the length of the belt used on the pipe roll machine. From this research can be concluded that: (1) In bending the thickness of 4 mm pipe the required power is 582.4 N with power of 0.4 hp then the motor required 1 hp, the diameter of the pulley used is 2 inch for motoran and 8 inch for the pivot reducer, belt used type B with length 44 inch, (2) To reach the rotation of ± 2 rpm ie pulley diameter used with the ratio of pulley ratio is 1: 4, the reducer is used with the value I = 60 and sprocket ratio 1: 3.

A new hybrid sewage treatment system combining a rolled pipe system and membrane bioreactor to improve the biological nitrogen removal efficiency: A pilot study

Abstract A new hybrid pilot plant configuration based on a modularized rolled pipe system (RPS) combined with a submerged flat sheet membrane bioreactor (MBR) was investigated to enhance the sewage treatment and membrane performance. The system was operated under actual conditions for more than four months, that is, at a constant flow rate of 30 m³/d and with two internal recycling ratios. The results indicate that the hybrid system produces an excellent effluent quality and considerably mitigated membrane fouling. The average concentrations of SS, COD, TN, NH4+-N, NO3−-N, and PO43--P remained below 2.81, 8.29, 8.77, 0.15, 8.17, and 1.49 mg/L, respectively. It was estimated that the periodic chemical cleaning of the membrane could be extended to approximately six months. The MBR and RPS can virtually complete nitrification and denitrification, respectively. The highest average denitrification rate of the RPS is 116.95 mg NO3-N/(g MLVSS d), with a hydraulic retention time of 1.05 h. Therefore, the RPS–MBR hybrid system has potential to improve the sewage treatability. The emerging RPS technique can obtain high rates of denitrification coupled with a compact design, ease of installation, and small footprint.

SOME FEATURES OF MILLS OPERATION COLD PILER PIPE ROLLING

Purpose. The establishment of the essence of many dynamic phenomena and the prediction of peak loads, both during the design or reconstruction stages of HPT mills and their operation using advanced calculation methods remain relevant. Methodology. An engineering technique to simplify a developed dynamic model is proposed, which includes the combination and development of known techniques. In addition, active mechanical connections in the original dynamic model of an HPT mill are identified, causing the pronounced parametric processes in the system under study. Findings. The study of the dynamics of simplified two-mass models of the HPT mill with combined parameters and periodically changing mass characteristics has been carried out. A differential equation of parametric oscillations in the drive power line has been compiled. The solution to the differential equation allows us to estimate the dynamic displacements of the considered drive of the working stand of the HPT mill for the most common modes of vibration of the mechanical system. Since the differential equations (8) are present in the formulation of the basic Cauchy problem, we implement the solution numerically, using the Runge - Kut method in the medium of a standard software product, for the most common first form of oscillations of a mechanical system. Originality. Dynamic features of the operation of the drive of the working stand of the HPT mill are presented in the form of angular displacements of the drive shaft of the mechanical system. The dynamics of the drive drive of the working stand of the HPT, 32-3 mill are calculated (pipe rolling along the route 38×3.8 → 19.1×2.1, material – steel Х18Н10Т). Practical value. The causes of the appearance of parametric oscillations in the drive system are identified and dynamic instability zones of the mechanical drive system of the HPT mill is installed, which allows for the selection of optimal rolling conditions at the design stage of technological processes. Keywords: cold rolling, pipe, mill, power line, main drive, dynamic model, simplified design scheme, mathematical model, parametric oscillations, differential equation, angular oscillations, dynamic instability.

Modeling and Simulation of a Stepping Robot on a Rolling Pipe

Modeling and Simulation of a Stepping Robot on a Rolling Pipe

Improving Pipe Production on the TPA 220 Piercing Mill

The introduction of pipe rolling from continuous-cast bullet on the TPA 220 piercing mill, with an expanded range (up to a diameter of 245 mm, as against the previous limit of 219 mm) and increase in pipe length, is described. The mechanical parameters of the mill are measured and assessed. Options for further modernization of the mill and the production of thin-walled pipe with a diameter/wall ratio of more than 30 are outlined.

Assessment of Technogenic Accident Risk of Industrial Building Structures

A methodology for assessing the risk of an industrial building accident was developed taking into account the damage caused by various localization of collapse. Before the beginning of the survey of a facility technical condition, groups including the same type of building structures are selected. Further, assessment is made for the reduction in their load-carrying capacity from the strength and stability conditions taking into account defects. The characteristics of the influence of defects and structural damage on a building safety is the degree of compliance with the standards expressed by the reliability level. Reliability levels assignment is carried out on the basis of calculations, operating experience and inspection of a particular type of structure according to the formalized rules. The risk of collapse according to a separate scenario is calculated for structures that are capable and incapable of causing a progressive ossification. The results of the technique application are based on the analysis of the accident risk at the welding shop “Vysota (Height) 239” of the Chelyabinsk Pipe Rolling Plant.

THE STUDY OF THE PROCESS OF ROLLING PIPES FROM ANISOTROPIC MATERIAL

The process of rolling pipe with simultaneous significant changes in pipe diameter and thickness is carried out at the mandrel stage. In the region of plastic deformation, biaxial stress and plane deformation state of a pipe take place. The area of biaxial stress state is characterized by the presence of two sections: a section of the sptial bending before the contact with the roll and a section which is in contact with the cylindrical surface of the roll. It is assumed that the material of a tube blank is incompressible, has a cylindrical anisotropy of mechanical properties, is anisotropically hardenable, for which the Mises-Hill yield condition and the associated law of plastic flow are valid. The article considers stress distribution in the areas of biaxial stress state. To take into account the anisotropic hardening of the material information concerning distribution of deformations in the region of plastic deformation was taken into account. The problem of stress distribution in the region of plane deformation state of the region of plastic deformation was considered. It is assumed that radial flow of the material occurs in the region and Coulomb's law of friction is realized at the contact boundaries of the workpiece and the tool. The change in the direction of material flow at the inlet and outlet of the region is taken into account by means of radial stress modification with regard to the discontinuity of the tangential component at the boundary of the deformation region by the work balance method. The expressions obtained for determining deformations and stresses makes it possible to analyze the process of rolling pipes at the mandrel stage taking into account material anisotropy. The obtained results can be used to create resource-saving technologies for processing metallic materials using new nanocomposite lubricants and coatings.

Study of thermal dehydration of sodium orthophosphate monosubstituted

Depending on the conditions of conducting the synthesis, it is possible to obtain polymeric phosphates of different composition and structure. The mixtures of polyphosphates, employed in the production of technological lubricants, are expedient to synthesize by the high-temperature dehydration of sodium orthophosphate monosubstituted. The temperature ranges, over which the thermochemical transformations of sodium orthophosphate monosubstituted with the formation of polyphosphates proceed, are established by the thermogravimetric method. The composition of polyphosphates is determined using the X-ray phase analysis. Quantitative composition of the mixtures of polyphosphates is determined by applying the original method of eluent ion-exchange chromatography. It is established that the basic products of thermal dehydration of sodium orthophosphate monosubstituted in the range of temperatures 200–650 °C are Na 3 Р 3 О 9 , Na 2 H 2 P 2 O 7 and Na 6 P 6 O 18 . Thermochemical transformations of NaH 2 PO 4 into Na 6 P 6 O 18 at temperature 650 °C are accompanied by the side reactions of formation of Na 3 H 2 P 3 O 10 . We proposed the chemical scheme of the high-temperature dehydration of sodium orthophosphate monosubstituted. Kinetics of the isothermal process of obtaining the polymeric phosphates from sodium orthophosphate monosubstituted at different temperatures is examined. We established quantitative composition of the mixtures of inorganic polymeric phosphates depending on the duration of isothermal process of dehydration. The possibility of obtaining a salt mixture of polymeric phosphates of the assigned qualitative and quantitative composition is demonstrated. We proposed to use the mixture: 76 % Na 6 P 6 O 18 , 8 % Na 2 H 2 P 2 O 7 , 8 % Na 3 H 2 P 3 O 10, 8 % NaH 2 PO 4 , obtained at 650 °C, as the basic phosphate component of technological lubricants for the hot rolling of pipes.

Mathematical modeling of steel chemical composition and modes of thermomechanical treatment influence on hot-rolled plate mechanical properties

Methods of economical alloying of high pipe steels were considered in the paper. Due to the large environmental, energy, and economic issues in the destruction of the pipeline, the quality of steel pipes is very important. The method described in this article is considered to be relevant not only for pipe steels but also for high-strength steels used in shipbuilding, bridge construction, etc. Review mechanisms of strengthening microalloyed steels were carried out in this work. Schema evolution of the microstructure of microalloyed steels was discussed. The influence of alloying elements in steel by means of optimal process parameters of thermomechanical rolling was analyzed. There are two methods of mathematical modeling used in the study: artificial neural networks (ANNs) which are based on the multilayered perceptron to select the optimal chemical composition and finite element analysis to optimize the process parameters. An experimental dataset was used to train multilayer perceptron (MLP) networks to allow for prediction of the yield strength, tensile strength, and elongation of steel. Due to large availability, low cost, and high accuracy of the results, these methods are considered to be the most promising ones. The mathematical model for calculating mechanical properties of a rolling pipe has been developed. Two ways to reduce the cost of a hot-rolled plate made of microalloyed steels were developed. There has been developed the complex of replacement technological impact which can make it possible to replace or reduce the amount of expensive chemical elements (vanadium, nickel, copper, manganese, chromium, and niobium) without loss of quality.

УПРАВЛЕНЧЕСКИЙ УЧЕТ ЗАТРАТ НА ПРЕДПРИЯТИЯХ ТРУБОПРОКАТНОЙ ПРОМЫШЛЕННОСТИ

Today metallurgical plants play a significant role in the Russian economy. According to current research studies in the Russian economy there are more than 28 000 enterprises, which offer different products and services in the sphere of metallurgical production. In general terms the indicated sector can be divided into ferrous and non-ferrous metallurgy. The first type plays a more important role. The separate segment of the ferrous metallurgy market is a pipe and tube production. The pipe rolling enterprises play a key role in the development of the economy of the Ural Federal District. In accordance to the data of statistical survey more than 100 000 people work in enterprises of the abovementioned industry, which makes up about 1/3 of all working population in the manufacturing industry. Moreover, pipe rolling plants also hold a significant position in terms of sales among enterprises which are engaged in different economic activities. Today administration of the majority of pipe rolling enterprises is facing a problem of forming effective cost accounting. Based on the data of several investigations one of the factor in achieving a sustainable competitive advantage is a possibility to reduce costs associated with the production and realization of pipe rolling products. The need for effective cost management is largely associated with their role in the process of profit generation. It’s the profit which ultimately serves as a main condition of the company’s sustainable economic development facilitating the achievement of competitive advantages on the market. In this regard for the most of pipe and rolling plants the profit maintenance by an effective continuous process of cost management is quite modern phenomenon in terms of current trends of financial and economic development.