Corrosion - раздел Иностранные языки, АНГЛИЙСКИЙ ЯЗЫК It Has Long Been Known That Metals Can Undergo Changes In Which They Lose The...
It has long been known that metals can undergo changes in which they lose their characteristic properties; in most cases, the metal ceases to be an element, and becomes a compound. Iron exposed to damp air is changed to a brownish hydrated oxide, known as rust. Iron placed in salt water with access of air also produces rust, and the change is known to be connected with electric currents flowing through the liquid. If heated in air, iron becomes covered with a dark scale, consisting, usually, of more than one oxide. If placed in dilute sulpheric acid, it passes into solution with evolution of hydrogen gas, and the solution on evaporation and cooling deposits crystals of ferrous sulphate.
The name "corrosion" describes these and similar chemical and electrochemical changes, in which a metal passes from the elementary to the combined state. However, the term is today sometimes used where a solid metal passes into solution in another (liquid or molten) metal - although this is not generally regarded as a chemical change; thus a steel vessel used for containing molten zinc slowly loses thickness the iron being dissolved by the zinc, the vessel is then said to undergo corrosion. We may also say that "corrosion" is the destruction of metal or alloy by chemical change, electro-chemical change or physical dissolution. This excludes mechanical processes which destroy the value of a metallic article by grinding it away as metallic dust. Such purely mechanical damage is called "erosion".
Conjoint Action. Often corrosion and erosion operate simultaneously and the damage produced is frequently far greater than the damage caused when they proceed one at a time. This disastrous combination of destructive agents is called "conjoint action". Certain types of conjoint action deserve special mention.
"Stress-corrosion cracking" denotes the cracking caused when a steady tensile stress acts on a metal in a corrosive environment, whereas cracking caused by alternating or cycling stresses in a corrosive environment is called "corrosion fatigue". Sometimes the cracking, whether due to stress-corrosion or corrosion fatigue, passes along grain-boundaries, and is then known as "intergranular corrosion", sometimes it passes across the grains, and is then called "transcrystalline-corrosion".
Oxidation. The conversion of the surface portions of metal to oxide on heating in air or oxygen is generally termed "oxidation". Oxidation is regarded as a type of corrosion.
Other Special Types of Corrosion. Generally corrosion starts on the surface of a metallic specimen. If a large portion of the surface is affected, it is said to be "general corrosion"; if only small areas, it is called "localized corrosion"; if confined to small points, so that definite holes are produced, we speak of "pitting". If corrosion produces grooves following grain-boundaries, or perhaps (on a much larger scale) following the water-line on a partly immersed metallic plate, we may speak of "grooving"; grooves may also be developed along the line, where two dissimilar metals meet, or in zones running parallel to a weld. If in rolled or extruded metals corrosion extends along certain planes parallel to the surface, it is called "layer corrosion"; under atmospheric conditions, the voluminous corrosion-product formed along these planes may lever the intervening layers apart, so that the material divides into flakes; this is known as "foliation".
Etching. The metallographist uses certain corrosive reagents to develop the structure of polished micro-sections. The reagents may show up the grains by producing crystal-facets, so that some grains appear dark and some bright when viewed under the microscope or it may attack the grain-boundaries, developing them as dark lines; or again it may attack and colour certain constituents of an alloy, which can thus be identified. Although these are all examples of corrosion the metallographist rarely uses the word; he speaks, generally of "etching" his sections.
Other scientists are actively engaged in corrosion work without employing the term. Metal-physicists treat metallic surfaces with certain acid mixtures, and count the pits which appear along grain-boundaries or on slip-planes, believing that they reveal to him the number of dislocations present. Other physicists study oxidation or film-growth, using the theory of lattice defects to interpret their results. But each of them is studying a corrosive process, and his work may be contributing much to our knowledge of the subject.
Дополнительные слова и словосочетания:
1) conjoint action – общее действие
2) stress-corrosion cracking - – коррозионное растрескивание под напряжением
My Speciality
I. Повторите и запомните следующие слова:
1) choose (chose,
chosen), v
– выбирать
2) daily, adj
My Speciality
There are many faculties in the South Urals State University. But those students who have chosen the career in metallurgy study at the Metallurgical department. I’m a student of the Metallurgical D
Ferrous and Non-Ferrous Metals. Alloys
I. Повторите, запомните следующие слова:
1) appearance, n – внешний вид
2) compose, v – составлять
3) dense, a – плотный
4) feature, n – особенно
Ferrous and Non-Ferrous Metals. Alloys
It is known that metals are very important in our life. Metals have the greatest importance for industry. About two thirds of all elements found in the earth are metals. It is diffi
Iron and Iron Ores
I. Повторите и запомните следующие слова:
1) associate, v – соединять(ся)
2) as well as – также, а также
3) cheap, a – дешевый
4) cost, n – стоимость
5)
Iron and Iron Ores
Iron is the only metal that can be found in almost every part of the world. It’s the fourth element in abundance on the earth, being exceeded by oxygen, silicon and aluminum. It is the cheapest of
Grey Cast Iron
I. Повторите и запомните следующие слова:
1) distribution, n – распределение, распространение
2) flake, n – чешуйка, хлопья (мн.ч.)
3) include, v – включать
4) s
Grey Cast Iron
Grey cast iron is one of the most valued of cast metals. It may be made by melting pig iron and scrap in the cheapest of melting processes, the cupola, and then cast into sand molds
Casting
I. Повторите и запомните следующие слова:
1) accurate, a – точный
2) allow, v – позволять, разрешать
3) cavity, n – полость, пустота
4) hot, a – горячий
Casting
Casting is the oldest method of forming metals. Basically it consists of melting and pouring liquid metal into a cavity of the desired size and shape and allowing the metal to solidify. There are n
Metals and Non–Metals
I. Повторите и запомните следующие слова и словосочетания:
1) alloying element – легирующий элемент
2) alkali metal – щелочной металл
3) base metal – основной металл
Metals and Non–Metals
Among the more obvious distinctions between different kinds of elements is that which divides metals and nonmetals. Metals are distinguished from nonmetals by their high conductivity for heat and e
Corrosion
I. Повторите и запомните следующие слова:
1) damp air – влажный воздух
2) deposit, n – осадок, осаждать
3) destruction, n – разрушение
4) dilute,
The Iron Blast Furnace
I. Повторите и запомните следующие слова:
1) carry up, v – поднимать
2) consume, v – потреблять
3) drop, v – опускать
4) float, v – плавать
5) flow, n –
The Iron Blast Furnace
Pig iron is one of the most important materials produced in the metallurgical industry. It is generally produced from the iron ore by chemical reduction process of iron conducted in
Bessemer Converter
I. Повторите, запомните следующие слова:
1) affinity, n – сродство, родственность
2) capacity, n – емкость, мощность, производительность
3) interior, n – внутренность, вн
Bessemer Converter
Molten pig iron, gaseous oxygen and steel scrap are the main constituents for making steel in the converter. Pig iron contains carbon, manganese, phosphorus, sulphur and silicon in
Open-Hearth Furnace
I. Повторите и запомните следующие слова:
1) damper, n – заглушка
2) capacity, n, v – емкость, производительность
3) checkerwork, n – насадка
4) combustion, n –
Open-Hearth Furnace
The phenomenal success of the Bessemer process attracted many other inventors to the study of new and improved methods of steelmaking. The only process which was destined to become a rival of the B
Electric Furnace
I. Повторите и запомните следующие слова:
1) accomplish, v – совершать, выполнять
2) advantage, n – преимущество, польза
3) arc, n – дуга
4) conductor, n – прово
Electric Furnace
Numerous types of furnaces utilizing electric current as the source of heat have been developed by a large number of investigators, but relatively few types have survived as practic
Continuous Casting of Steel
I. Повторите и запомните следующие слова:
1) apply, v – применять, прикладывать
2) completely, adv – совершенно, полностью
3) conventional, adj – общепринятый, стандартны
Continuous Casting of Steel
Continuous casting as at present applied to the production of steel may be defined as a process in which liquid metal is poured into an open-ended mould, from the lower end of which a partially sol
Types of Mills
I. Повторите и запомните следующие слова:
1) accessories, n – принадлежности, арматура
2) billet, n – заготовка, сутунка
3) blooms, n – блюм, стальная болванка
4
Types of Mills
The three principal types of rolling mills used for the rolling of steel are referred to as "two-high", "three-high", and "four-high mills". As the names indicate, the
The Physics and Chemistry of Metallurgy
I. Повторите и запомните следующие слова:
1) fundamentals, n – основы
2) matter, n – материя, вещество,
3) correlation, n – соотношение
4. to reveal, v –
The physics and chemistry of metallurgy
Metallurgy is a science dealing with the constitution, structure and properties of metals and alloys, and the processes by which they are obtained from ores and adapted for the use
Relation of Metallurgy to Physics and Chemistry
I. Повторите и запомните следующие слова:
1) involve, v – включать в себя, подразумевать
2) outwardly, adv – внешне, снаружи
3) earthy, a – земляной, зерн
Relation of Metallurgy to Physics and Chemistry
In principle, steelmaking involves only a relatively, outwardly simple steps. Principal iron ores consist of combinations of iron with oxygen (iron oxides), mixed with varying percentages of useles
Protection of Steel from Corrosion
I. Повторите и запомните следующие слова:
1) application, n – применение, приведение в действие 2) environment, n – окружающая среда
3) coat, v – грунтовать, нанос
Protection of Steel from Corrosion
Everybody knows how widely steel and iron products are used. But almost in all applications regardless of the environment, these products are coated by some means in order to preven
Induction Furnaces. Puddling Furnaces.
I. Повторите и запомните следующие слова:
1) core, n – сердечник, стержень
2) excess, n – избыток, излишек
3) insure, v – обеспечивать
4) quite, adv – впо
Induction Furnaces. Puddling Furnaces
Induction Furnaces. Induction furnaces are of two types – the coreless high-frequency type and the cored units which operate at low frequency. Principles of operation of both units are simil
Problems of Automation of Blast Furnace
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1) considerable, a – значительный, важный, большой
2) associated, а – связанный, объединенный
3) denote, v – означать
Problems of Automation of Blast Furnace
In the course of the past few years, a considerable amount of time and money has been spent studying the blast furnace process, and discussing with the operators some of the problems associated wit
Hot Working and Hot Working Processes
I. Повторите и запомните следующие слова:
1) bar, n пруток, – брусок
2) draw, v – тянуть, волочить (проволоку)
3) hammer, n,v – молот, ковать
4) prevent, n – пре
Hot Working and Hot Working Processes
Hot working entails plastic deformation of metals at temperatures where strain hardening does not occur. Hot working is done for two reasons: to shape metal into useful objects; and
Cold Working and Cold Working Processes
Cold working drastically changes the mechanical properties of metals, the most important being increase in strength and hardness with a simultaneous reduction of ductility. The meta
Oxy-fuel combustion for reheat furnaces
Steel Times International APRIL 2002
The use of oxy-fuel burners in reheat furnaces greatly reduces the volume of flue gas produced which in turn leads to lower h
Heat transfer.
The total heat transfer occurring within a furnace can be broken down into four main areas:
– radiant heat transfer from the flame to the product;
– radiant heat transfer from the
Benefits of oxy-fuel combustion.
The main benefits of oxy-fuel can be summarized as:
Higher furnace productivity. As a result of the improved thermal efficiency of the furnace and the improved heat transfer charact
Energy efficiency.
The steel industry's generation of carbon dioxide (CO2) is mainly associated with the chemical reaction of carbon and iron ore in blast furnaces producing molten iron, which is then conv
Energy taxation.
The European Commission proposed in March 1997 a Directive for restructuring the Community framework for the taxation of energy products – COM(97) 30 – and various alternatives have been discussed
Emission trading.
On 23 October 2001 the European Commission adopted a proposal for a Directive of the European Parliament and of the Council establishing a framework for greenhouse gas emission trading within the E
Mill roll lubrication to cut costs
A 15% reduction in mill power consumption, a 10% increase in work roll life and a 20% reduction of mill load are the result of employing hot mill roll lubricants. The correct sel
Cold rolling.
Different parameters are required for the cold rolling mill, where the selection of a robust product will pay for itself in terms of maximizing speeds and strip quality, increasing roll life and ex
Uzbekistan woos foreign investors
Uzbek iron and steel works Joint Stock Manufacturing Amalgamation (Uzmetcombinat) was established in 1994 through a merger of the Uzbek metallurgy plant, the Shirin machine building
СПИСОК СОКРАЩЕНИЙ
1. General Electric Co. – Company
2. Ltd (Britain) - limited responsibility – корпорация из нескольких
владельцев и вице президентов 3. OD. – outside diameter 4. ID. – ins
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