| RUS |
During last ten years at many industrial enterprises, there was a down level
of man-caused safety. Which depends on progressive ageing of the fixed capital stocks, absence or a slow pace of reconstruction and renovation
of equipment. In particular, the metalware at the majority of the enterprises operates in aggressive conditions, which make them out of order
as a result of simultaneous influence of mechanical factors, corrosion and their total influence.
The corrosion of metals and metalware causes a great damage for the industrial enterprises, in particular
for chemical-recovery factories. The losses from corrosion of metals consists of the costs of manufacturing of the metal constructions, disabled
in consequence of corrosion and of the irretrievable losses as products of corrosion and indirect losses.
The basic direction in the area of maintenance the man-caused safety of the metalware is studying of
the properties and behavior of materials in the aggressive environment, receiving dependence of the corrosion rate from substance
concentration for various kinds of steel, development of new kinds of corrosion-proof steel and also development of new kinds of
sheeting. One more kind of prolongation of a resource and increase of man-caused safety of the metalware is mechanical and
heat treatment of the material and creation of databases for forecasting the corrosion destruction of designs.
The numerous designs which work in conditions of aggressive solutions or atmospheres,
frequently are exposed to corrosion-mechanical destruction under the joint influence of corrosion environment and mechanical factors.
The system of maintenance of man-caused safety of the metalware is offered, which is based on the
system approach, which will allow to determine the corrosion condition of the metalware with the larger accuracy in the process of
exploitation, to choose this or that way of protection, taking into consideration a condition of work and corrosion activity of
the environment, to determine the economic benefit from a complex of protective measures, both at a stage of designing and for
existing metalware. The system is developed for basic metalware (piers, overlapping, trusses, guides etc.).
This system is developed for the metalware, that perceive only static load and are made of
various structures and subjected to corrosion, this factor is known from the experience of work in the given conditions.
For creation of any model it is necessary to enter some conditions (assumptions) for the
metalware working in the conditions of chemical-recovery factories, such as corrosion rate, kinds of structures used at
manufacturing and to determine the loading influence on them.
The basic condition of serviceability of the metalware is the criterion of durability:
σ ≤ [σ] = σв / n
Тhe coefficient of safety factor “n” of the elements of the metalware
is nominated depending on a degree of their responsibility (the level of technological danger, the weight of consequences at failure,
the size of territorial risk etc.).
In this turn the strain of the metalware depends on many other factors or parameters:
σ = f (F;J;W;i)
These listed parameters show the characteristic opportunities of
the chosen section, that allows to choose a necessary structure for given metalware.
For realization of the given approach, it has been developed the database for the marks of steel
used in the metalware, the standard structures, the rate of corrosion in the basic corrosion environments. The program that allows
to determine changing of the basic parameters of structure depending on corrosion with a fixed or variable step has been made. It allows
to determine changing of the basic geometrical and mass-centering characteristics, such as the sectional area, the moments of
inertia and resistance of section. From the experience of exploitation of the metalware at any factories the average rate of
corrosion in the given conditions is already known, that allows to determine the possible changes at the time of above mentioned
parameters of the metalware.
The next point of the system is the creation of the base methods of protection and the area of
application under various conditions of exploitation of the objects and their expediency of application as well as the description of the
recommendations for the projected, working and general approaches and measures for prolongation of the metalware resource.
The basic methods of the protection are the mechanical or chemical treatment of the surface
of the metalware with the subsequent drawing of various kinds of sheeting, such as paintwork materials.
The order of actions that are to be made to increase the level of protection of the working
constructions from corrosive attack and protection of ones under installation will be composed.
In this work a new approach to the decision of the problem of maintenance of man-caused
safety of the metalware and forecasting of corrosion process of degradation in the process of exploitation is submitted. The given
approach will allow to determine corrosion conditions of constructions in the greater accuracy, to reduce economic expenses
for repair and premature replacement of the metalware, and also it will allow not to increase a level of safety using only
necessary material at designing and installation.