Natalia Kolokolova

1 Introductory part

Introduction

    Final stage of metallurgical repartition is hire manufacturing. In the given technology the greatest quantity of gears (to 50-60 % from their general number) are connected with conveyance of hot preparations. A special role in the given technological chain carry out oven rol'gangs which are a relaying and accepting link between the heating furnace and the rolling mill. The basic requirement to rolling mill gears (and rol'gang in particular) is maintenance of non-failure operation of the gear throughout all process proskating rinks. Reliability oven рольгангов is high enough. However occurring refusals lead to idle times to all technological chain of the rolling unit. Expenses are thus estimated hundreds thousand grivnas.
    Reliability theory studies laws of occurrence of refusals and restoration of working capacity of a product, influence of external and internal influences on reliability of technical devices, methods of quantitative definition and modes of maintenance of the set level of reliability at designing, manufacturing and operation of products. Terminology of the theory of reliability is regulated GOST 27.002-83 which extends on all kinds of technical objects. With reference to the metallurgical equipment as object we will understand any cars and gears, knots and separate details.

Work urgency

    The modern equipment of the metallurgical enterprise should answer high indicators of reliability, in particular to non-failure operation. Because technological lines of metallurgical manufacture, especially rolling, engage considerable number of gears of an order 200-it of cars and still an order 50 rol'gangs. Quantity of details in each gear of an order 100-200. Refusal of one element leads to a stop of all technological chain, therefore studying of questions of non-failure operation with reference to rolling manufacture is an actual problem of the present.

The work purpose

    The work purpose consists in probe информативности the data about refusals oven rol'gangs a sheet-rolling camp 2300.
    The primary goals of work: drawing up of sequence of the analysis of refusals oven rol'gangs a sheet-rolling camp 2300 and estimations of quality of work of line fault service.

2 Theoretical part

The theory of reliability

    Reliability is a property of object to keep in time in the established limits of value of all parametres characterising ability to carry out demanded functions in set modes and conditions of application, maintenance operation, repair, storage and transportation.
    Working order: this condition at which the device corresponds to all requirements engineering specifications. Faulty condition: this condition at which the device, the object does not correspond at least to one of requirements standard – engineering specifications.
    Efficient condition: this condition of object at which it is capable to carry out the set functions, keeping values of the set specifications within established by the documentation. Disabled condition: this condition at which values at least one set parametre do not correspond standard – engineering specifications.
    Non-failure operation: property of a product in which it continuously keeps working capacity during some time.
    Maintainability: the property of a product consisting in fitness to the prevention and detection of the reasons of occurrence of its refusals, damages and their elimination by repair and maintenance operation.
    The durability is a property of object to keep an efficient condition before a limiting condition at the established system of maintenance operation and repair. The basic indicator of durability - a technical resource – an operating time of object from the beginning of operation or major repairs before the limiting condition, expressed in indicators of a total operating time or life cycle.
    Keeping – properties of object to keep value of indicators of non-failure operation, durability and maintainability during or after storage or transportation.
    It is possible to present "classical" character of change of reliability of any product in the form of a stream of refusals, thus use laws: normal and distribution of Vejbulla.
    Causes of failures can be both operational factors, and imperfection of designing, manufacture and installation of equipment [2,4,6]

In drawing 78 kinds of refusals in metallurgy are resulted. In each metallurgical equipment it is necessary to consider each element of the car consistently.
    It is necessary to notice that the most frequent cause of failures are defects of minor details of the equipment. Thus in difficult systems redundancy use cannot raise reliability though redundancy can be active or passive. In the first case all elements of system work with an overall load, in the second - the reserve element is engaged at failure of the reserved. The quantity of the industrial errors which are at the bottom of these refusals, can be reduced by means of the qualitative technological control. Infringements of technology in the course of assembly - a special cause of failures.
    Data of existing classification is superfluous and does not allow to execute the functional actions necessary for liquidation of refusals.

The information theory

    The object of steering is a set of cars and gears for which work with the set operating ratio the rules defining sequence of technological and regenerative operations should be executed. Steering body is staff of mechanical service. Components are connected among themselves by channels of information. On input channels of steering body the information from an environment (for example, plans) and the industrial information from object of steering arrives. The leaving information engages commands of steering of maintenance operation of the equipment and the accounting data in an environment.

    Some methods of probe used in control systems are known: the system analysis, principles of an optimality, modelling, «a black box», external addition.
    At use of a principle of simple digital coding for working out of qualifiers of knots and details there are serious difficulties as the quantity of knots in shop is estimated in thousand, and details-tens of thousand. If to each knot and a detail to assign individual number qualifiers will be bulky. Hence, it is necessary to develop such principles which would allow to create codes, first, as much as possible convenient for attendants and, secondly, compact for increase of degree of use of the COMPUTER. [6, 7, 3]

    This problem can be solved as follows. From block diagrammes of cars it is visible that despite the big variety of knots and details, their functions are limited. For example, in each car the working body, a transmission gear and the engine incorporate clutches which to a functional sign are classified on intermediate and motor (a code of knot 20). In metallurgical cars there are various on a design motor clutches, but all of them have the barrel (a code of a detail 01) a leading shaft. Thus, in what car of shop there would be no motor clutch, the code of the barrel of a shaft of the engine will be 2001.
    Result of processing of the initial information on the COMPUTER are two kinds of the steering information: operative and perspective. Operative-this the generalised data about equipment refusals for one month. [7]

Animation

Figure 3 - The scheme various kinds of development of fatigue cracks in a detail (animation in volume - 15,6 кВ, consists of 8 shots, 7 repetitions)

3 Final part

Conclusions

    During work performance the multiple-purpose management under the analysis of refusals for any metallurgical equipment will be created. Also creation of sequence of an estimation of quality of work of line fault service.

The literature

    1. В.А.Сидоров. Механическое оборудование. Техническое обслуживание и ремонт (краткие заметки) – Донецк, 2007. – 270 с., 114 илл., 43 табл.
    2. ГОСТ 27002–89. Надежность в технике. Основные понятия. Термины и определения. - М.: Госстандарт СССР, 1990. – 18
    3. Дмитриев В. И. Прикладная теория информации - М.:Высш. шк., 1989. - С. 320.
    4. Дружинин Г. В. Надежность автоматизированых производственных систем - М.:Энергоатомиздат, 1986. - С. 480.
    5. Кравченко В. М. Техническое обслуживание и диагностика промышленного оборудования: Монография.-Донецк: ООО "Юго-Восток, Лтд", 2004.-504с.
    6. Седуш В. Я Надежность ремонт и монтаж металлургических машин. Донецк, Вища школа, 1981
    7. Седуш В. Я Организация технического обсуживания металлургического оборудования.-К.: Техника, 1986.-С. 121
    8.Проников А. С Надежность машин – М.: Машиностроение, 1978. – 592 с.
    9. Эксплуатационные свойства металлургических машин. Ловчиновский Э. В., Вагин В. С. М., "Металлургия", 1986, С.160
    10. http://www.cultinfo.ru/fulltext/1/001/008/093/230.htm"
    Сайт содержит обзорную информацию по прокатному производству и другм областям металлургии
    11. http://www.ifsrussia.ru/publmckinsey2.htm
    Основные вопросы надёжности механического оборудования.
    12. http://www.polezen.ru/publ/index.php
    Статьи по надёжности оборудования и эксплуатации.