Tihonovich D U Individual task
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MUCH LANGUAGE TRANSLATION OF ABSTRACT OF THESIS OF MASTER'S DEGREE WORK

Tihonovich Denis Urjevich

Donetsk national technical university

Faculty Mechanical

Speciality "The Mechanical equipment of factories of ferrous metallurgy"


    

Tihon-@mail.ru

Theme of masters works:

Research of reliability and longevity of working of rolganga cage of a 950 state 950/900 at the "Istil (Ukraine)" plant condition.

The head of work: the senior lecturer of faculty " MOZCHM "
Oshovsca Helen Vladimerovna


Autobiography Final work of the master Electronic library Links on a subject Report

  Actuality of theme
  Purpose and tasks
  Scientific novelty
  The planned practical result
  Review of existent researches
  Own results
  Conclusion
  List of the used literature

        Actuality of theme

        Rolled production is the finishing stage of metallurgical process. A working roller table takes a leading plасe in the technological line of rolling, as its shutdown results in the rise of accident rate in a workshop and in the end the productivity of the whole workshop goes down .
        The operation of a working must be faultlessness, therefore in a workshop the areas and proper equipment and equipments for maintenance and renewal of its capacity must be foreseen.
        A working roller table is one of the most loaded mechanism of the rolling mill. Therefore the rise of faultlessness and longevity of a working roller table is an important task. Solution of the tasks related to the reliability of work of a roller table will allow to increase efficiency of its operation. For the successful solution of these tasks it is necessary to conduct the analysis of loading of a roller table, kinds and reasons of refusals of its components.
        Longevity of a working roller table, and also metal consumption of its construction affect the power requirement of a machine.
        Removal of errors arising while mounting such as in correct centring and balancing of rollers the removal of misalignment considerably lower the dynamic loading which arises during operation of a working roller table, and increase the efficiency of its application. Discrepancy between the roller table design and working conditions also has a strong influence on longevity of working roller table components.
        Therefore it is necessary to pay a considerable attention to the question of faultlessness and longevity of a working roller table, as the quality of products and productivity of a workshop depend on this.

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        Purpose and tasks

        A working roller table is one of the most loaded mechanism of a rolling mill. Therefore the rise of faultlessness and longevity of a working roller table is an important task. Solution of the tasks related to the reliability of work of a roller table will allow to increase efficiency of its exploitation.
      -  Research tasks:
      1)   to analyse the indexes of faultlessness and longevity of working of a roller table cage 950 on the basis of statistical data about its operation;
      2)   to develop theoretical basis of calculation of loading, indexes of faultlessness and longevity of elements of a working roller table; to define loading, indexes of faultlessness and longevity of working of a roller table cage 950;
      3)   to explore the tense-deformed state of a roller table roller knot.
      -   Research purpose - to expose and learn factors which stipulate faultlessness and longevity of elements of a working roller table.

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        Scientific Novelty

        The laws of a working roller table rollers loading have been set.
        The executed theoretical estimation of the tense-deformed state of rollers of a working roller table by means of the method of finite eventual elements, has been done that allows to lay the structural features of the improved construction.
        The factors stipulating faultlessness and longevity of elements of a working roller table have been exposed and learned.

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        The planned practical result

        To analyse the indexes of faultlessness and longevity of a working roller table cage 950 on the basis of statistical data about its exploitation; to develop theoretical foundations of loading calculations, indexes of faultlessness and longevity of elements of a working roller table. to define loading, indexes of faultlessness and longevity for working of a roller table cage 950; to explore the tense-deformed state of a roller table roller knot. All these will allow to increase the efficiency of a roller table operation.

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        Review of existent researches

        There are the folldwing groups of roller tables according to their purposes: working , to serves the technological machines; transport to feed the rolled metal to the technological machines; special, to transport billets, and do a number of other operations. They can be annealing, shaking, movable, packing and so on.
        Working roller tables are the most loaded machineries with large number of working hours, (> 1000)a hour, shock application of forces, multichain systems with a general reason.
        On a fig. 1.1 [1], a scheme of a working roller table with the small step of rollers 4, is given to feed short bars (billets). The rollers have a general drive with a transmission shaft and conical transmissions 2, which are mounted in one case with lubricating bath for a gear box 1.

Rolgang roller

Fig. 1.1 – Sheme of a roller tablewith a group drive with the conical (б) and cylinder (б) transmissions


        Another kinematic scheme of a working roller table is characteristic for pressing , thick sheet and billet rolling mill (fig. 1.1b) [1].
        The rotation of rollers takes place through a distributive gear box with the cylinder transmissions. Torque moment from a gear box 3, is passed by a roller 1 through the transmission shafts 2 with tooth-type coupling or Gouca hinges .
        In the given course project a working roller table of cage 950 in the workshop of a primary mill is dealt with; the kinematics scheme of which is given on fig. 1.2 [1]. Roller table consists of 11 rollers. First three rollers, set before a cage, have an individual drive from the direct current engines D814 U2. Next 8 rollers have a group drive from two engines D814 U2, through a distributing gear. The low gear of a reducing gear is divided and is a helical one. The output shafts of a reducing gear are connected with rollers by means of tooth-type couplings.

Rolgang roller

Fig. 1.2. – Scheme of a working roller table cage 950


        Rollers fulfil the function of transporting a bar to the working cage. In the process of a bar moving rollers undergo pressure from the side of a bar, and pass this pressure to the bearings.
        While operation a working roller table can work in one of the following modes of operations:
      1)   ingof transporting and rolling;
      2)   ingot turning on a roller table;
      3)   idling;
      4)   reception of a rolled ingot out of a cage.
        Each of the above listed modes is characterized by its own modes of loading of a roller table components.
        Rollers are the working organ of a roller table, therefore loading acting on a roller table are considered in relation to rollers.
        Loading on all the other details and knots of a roller table ( rollers bearing, gears and tooth gear of a distributing reducing gear, reducing gear bearing, reducing gear shafts and coupling) can be received according to the set loading on rollers.
        Transporting of ingots and rollings is the basic mode of operations of a working roller table (to the related time taken). For this mode loading on rollers will be determined by ingot weight and its length.
        Loading on one roller is inversely proportional to the number of rollers which are simultaneously in contact with rolled metal. After each passage in a rolling cage the ingot weight is distributed among bigger number of rollers, loading on rollers and torque moment transmitted to the components of a roller table drive accordingly reduce.
        It is considered that the ingot weignt while transporting is perceived by 3 rollers (fig. 2.1a) [1].
While transporting of a rolled ingot, when its length exceeds 2 steps between rollers, loading on one roller can be defined as the rolled ingot mass, related to the number of rollers which a rolled ingot lies on (fig. 2.1b) [1]. But in practice some number of rollers do not contact directly a rolled ingot, due to its unevenness, it is assumed, that 70% of all rollers are in contact with a rolled ingot.
        During idle work of a roller table rollers undergo loading only from their own gravity force.
        In the modes of a roller table turning (fig. 2.2a) [1] the dynamic loading operates on rollers .
        Besides that dynamic loading acts on the rollers of a roller table from a cage. There are two possible variants of a rolled ingot leaving a cage (fig. 2.2б, and 2.3) [1].
        While rolling with lower pressure is ring rolling given on rollers from above. In the case when a ring rolling is bent on leaving a cage it abuts against a roller (ris.2.3) [1], as a result slip of a rollid ingot is possible.
        Loadings acting on the roller table rollers while transporting of a ring rolling and its turning are considered in master’s degree work.

Rolgang roller

Fig. 2.1. – Presenting solid in wolfs

Rolgang roller

Fig. 2.2. – Schemes of a roller table loading while transporting of: a) initial ingot; b) – rolling; c) – on leaving the rolls.

Rolgang roller

Fig. 2.3. – Schemesof dynamic forces action on a roller: a) – while ingot turning over; b)– while rolling with lower pressure

Rolgang roller

Fig. 2.4. – Schemes of forces action when rolling comes into contact with a roller.

           Own Results

        ANALYSIS OF A WORKING ROLLER TABLE FAILURES, REASON OF FAILURES


        Having analysed a register, 39 failure reasons have been selected:
          1) wear of rolling bearing;
          2) wear of rolling of p/s;
          3) wear of rolling bearing;
          4) destruction of rolling bearing of h/s;
          5) destruction of rolling bearing of p/s;
          6) destruction of bearing;
          7) lubrication shortage POUHS;
          8) lubrication shortage POUPS;
          9) lubrication shortage;
          10) loosening a threaded joint of h/s;
          11) loosening a threaded joint of p/s;
          12) loosening a threaded joint;
          13) revision POUHS;
          14) revision POUPS;
          15) revision;
          16) wear of rolling bearing of a distributing reducing gear;
          17) loosening of threaded joint r.r.;
          18) destruction of threaded joint r.r.;
          19) destruction of a rolling bearing r.r.;
          20) wear down of a gear;
          21) destruction of end-tail;
          22) lubriation shortage;
          23) dislocation of bearing rings;
          24) destruction of pillows;
          25) wear of gaskets;
          26) wear of fit place;
          27) revision r.r.;
          28) wear roller wear;
          29) wear of fit place;
          30) destruction of a tooth rim;
          31) loosening a threaded joint;
          32) lubrication shortage;
          33) wear of tooth type coupling;
          34) round of tooth type coupling;
          35) revision;
          36) friction is out of adjustment;
          37) destruction of a pillow;
          38) crack;
          39) reason unknown.


        On fig. 3.1 we can see the resulted histogram of destributing the number of quantity of refusals according to their reasons. It is visible from the histogram on fig. 3.1, that the main reasons of defects are: 7) Shortage of lubrication in a bearing knot from an idle side; 8) Shortage of lubrication in a bearing knot from a drive side; 12) loosening of a threaded joing; 15) Revision; 31) loosening of a threaded joint; 32) Lubrication shortage.

Histogram

Fig. 3.1. – «Refusals – reason of refusals» of a working roller table cage 950


        On fig. 3.2 distributing of refusals on the knots of a roller table is shown . It is visible from a histogram, that the great number of refusals arises up in a bearing knot from an idle side, in tooth type couplings, and in a distributing reducing gear.

Histogram

Fig. 3.2. – «Refusals – knot» of a working roller table cage 950


        REFUSAL – TIME


        Analysing the refusal – time we come to the conclusion, that during the period from 1998г. to 1999 and from 2000 to 2001 there were a plenty of refusals, but then there was the continuous reduction of refusals. It was due to the observance of rules of exploitation and rules of roller table service by technical repair personnel.
        On average breakages during a period from 1998 to 1999 were: destruction of bearing of a bearing knot from the drive side 0,5 months; wearing of bearing of a bearing knot from the drive side 1,3-months; wearing of roller 0,5-months; loosening a threaded joint 0,5 masses-months; wearing of bearing in the distributing reducing gear 1,5-months; wearing of bearing of a bearing knot from an idle side.
        On average breakages from 2000 to 2001 were: destruction of bearing of bearing knot from the drive side 1,75-months; wearing of bearing of bearing knot from a drive side 1-month.; wearing of fitting place of roller 1-months.; wearing of roller 1-month.; wearing 1-month.; loosening a threaded joint 0,5-months.; wearing of in a distributing reducing gear 1-months.; wearing of bearing in a distributing reducing gear 1-month.; wearing of bearing in the bearing knot in an idle side 2-months.; destruction in the bearing knot of idle side 1 month.

Histogram

Fig. 3.3. – «Refusals - time» of working of roller table cage 950


        ANALYSIS OF HISTOGRAMS


        Histogram «Refusals - time»

        Analysing a histogram «Refusals - time» received as a result of the data processing of a register, we can see that during the periods from 1998 to 1999 and from 2000 to 2001 year there were a plenty of refusals. While analysing histograms main attention was paid to exactly this interval of time, during this period a register was conducted with high quality.
        It is necessary to pay, as much as possible attention to the question of faultlessnees and longevity of a working roller table, as the quality of products and productivity of a workshop depend on it.
        Histograms «Refusal – knot» and «Refusals – reason of refusals»

        More often we can see the refusal (repair action) of knots of a working roller table. It is connected with loading a roller table perceives in the process of the work, which undergoes the most loading.
        Analysing the received histograms, we see:

        Threaded joints on most knots of roller table are weak points.
        Timely feed of lubrication is a very important factor of normal work of knots of roller table. Interruptions with the feed of lubrication can lead to growth of wearing the knots.
        The large number of refusals (repair actions) happened on a tooth type coupling. It is necessary to pay attention to this knot.
        Often bearing of rolling are out of order, particularly bearing knots from an idle side fail more frequent, than from a drive side.
        A plenty of the analysed refusals (repair actions) can not be subjected to clear classification. It is due to the fact there are simply no set norms of conducting the register and everybody filled it in his own way.


        CALCULATION OF A STRESSFUL STATE OF A ROLLER TABLE IN ANSYS PACKAGE

roller

Fig. 4.1 – Distribution of equivalent tensions in a roller

roller

Fig. 4.2 – Deformation of a roller

roller

Fig. 4.3 – The Geometrical model of a roller


        To study the distribution of tension arising up in the body of a roller at the turning of a bar, the simulation a ANSYS package was made.
        For this purpose on the basis of a roller drawing the geometrical model was created, see fig 4.3, and the properties of roller were set: material – module of resiliency was 2*10^5 MПа and Pouassona coefficient was m=0.3. Further a model was broken into eventual elements. A tetraid with 10 knots was used as an element. Surfaces on with the bearing, were fixed, and as the external loading the force was exerted which was equal to dynamic force arising while turning a bar with the cross section 645x660 and equalt 2MH, see addition 2, force was exerted as concentrated on the center of roller.
        As a result deformations and distributed tensions in the roller, see fig. 4.1, and the distributed tensions , see fig. 4.2, were received.
        As we can see from pictures maximal deformation was 2mm in the point of applying the force, and equivalent tensions were calculated on the 3th theory of durability on the center of a barrel of 110 MT, and maximal 330 MT. Maximal tension arises up in transition from a pin to a conical part of a roller.
        The received tensions do not exceed the legitimate values for roller material.

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          Conclusion


        During implementation of the work the following tasks were executed:
        Indexes of faultlessness and longevity of operation of a roller table cage 950 on the basis of statistical data about its exploitation were analysed.
        Theoretical positions of loading, calculations indexes of faultlessness and longevity of elements of a working roller table were developed.
        Loading, indexes of faultlessness and longevity for a working roller table cage 950 we defined.
        Tense-deformed state of a roller knot of a roller table was researched.
        Calculations of the tension state of a roller of roller table in a package ANSYS were wade.

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        List of the used literature


        1. Розрахунок машин і механізмів прокатних цехів: Ф.К. Іванченко, В.М. Гребеник, В.І. Ширяєв.-К.: Вища шк., 1995.-455с.

        2. Королёв А.А. Конструкция и расчёт машин и механизмов прокатніх станов: Учеб. Пособие для вузов.-2-е изд., перераб. и доп. – М.; „Металлургия”. 1985. 376с.

        3. Марутов В.А. и Павловский С.А. Гидроцилиндры. Конструкция и расчет. – М "Машиностроение", 1966. – 315 с.

        4. Производство блюмов, слябов и заготовок из углеродистых и легированных сталей в обжимном цехе. Технологическая инструкция. ТИ – 234 – П.03.01 – 95. Донецкий металлургический завод.: – Донецк, 1995. – 225 с.

        5. Целиков А.И., Полухин П.И., Гребеник В.М. и др. Машины и агрегаты металлургических заводов. Том 3. Машины и агрегаты для производства и отделки проката. – М.: Металлургия, 1988. – 576 с.

        6. Королев А.А. Конструкция и расчет машин и механизмов прокатных станов. Учеб. пособие для вузов. – М.: "Металлургия". 1985. – 367 с.

        7. Анурьев В.И. Справочник конструктора-машиностроителя: В 3-х т. Т.1. – М.: Машиностроение, 1982. – 736 с.

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Autobiography Final work of the master Electronic library Links on a subject Report






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