The territorial location of the world’s iron and steel industry

The features of the most important regions of ferrous metallurgy are clearly revealed when analyzing the structural and geographic shifts in the industry. There have been profound changes in the structure of its individual productions. The main trends are the improvement of the quality of the products (and correspondingly the prices) of all metallurgical operations, the reduction of energy and other costs for its production. At the same time, the demand for an ever wider range of final stages of the metallurgical cycle is continuously growing. There was a refusal of development of deposits of raw materials of poor quality, the transition to the creation of small-capacity enterprises instead of traditional large-scale plants.

In the developed countries of the market economy, the recovery and the rise of the industry in the first post-war decades were followed by deep recessions in the 1970s and 1980s. They were the result of oil crises of those years, which sharply reduced the demand for metal. In these countries, steel smelting in some years decreased by 60-70 million tons, which corresponds to the level of its production in the state with the largest metallurgical industry.

Western Europe – the oldest region of the world’s metallurgical industry – remains one of the leading in the level of development of the industry. Having exhausted his limited resources of raw materials or refusing to extract low-quality ore, he was forced in the post-war years to begin a broad structural overhaul of his ferrous metallurgy. The main areas and centers of the industry in Germany, France, Great Britain, in addition, experienced a heavy environmental burden of metallurgical enterprises. As a result, for the years 1938-1995. The share of Western Europe in the world in smelting pig iron decreased more than twice (from 48 to 19%), and steel from 42 to 21%. The share of coke has declined particularly from 55% to 11% in the world, and mining of iron ore tenfold (from 40% to 4%).

As a result of structural changes, a new specialization of most of the countries of the region has now taken shape: on obtaining high-quality steels (for example, Western Europe produces almost 1/2 stainless steel) and manufacturing a variety of, including precision, rolled products for powerful engineering (about 20% Weight in the world and up to 25-27% at its cost). All this led to the formation of a new geography of the region’s ferrous metallurgy, which was most clearly manifested in the territory of its large countries. Among them, the leaders were replaced: along with the FRG, the leading in the industry was Italy, which does not have any kinds of raw materials and fuel for obtaining metal. In total, both countries account for more than two-fifths of the smelting of pig iron and steel in the region.

The role of North America in the world’s iron and steel industry is determined by the United States. With considerable resources of iron ore, some types of alloying metals and abundant coking coal reserves, the country has for many decades experienced no difficulties in the development of the industry. A number of alloying metals it supplies Canada. Constant demand for ferrous metals was shown by metal-intensive branches of machine building, especially transport, a wide scope of construction, laying of roads, etc. It greatly increased during and after the Second World War in connection with the deployment of weapons production.

Having occupied in those years the leading positions on the level of development of the industry in the world, the region retained its leadership during several postwar decades. Thus, the USA held the world championship in the extraction of iron ore until the 1950s, in obtaining coke and pig iron up to the 60’s, and in steel smelting up to the 70’s. The change in the role of the United States and the region as a whole in the world was due to the structural reorganization of the industry, which raised it to a new high technological, technical and organizational level. Using the achievements of scientific and technical progress allowed to overcome the decrease and deterioration of the quality of own resources of raw materials, to achieve effective use of imported long-range iron ore. The import of cheap cast iron and rolled products from Mexico and other countries of different regions also increased sharply.

In the US, for the first time, the creation of miniature and midi factories in the industry began – in 1996 they smelted 42% of steel in the country. Technical and technological policy led to the elimination of open-hearth production, given the size of the industry, later than in other countries, but the share of obtaining electric steel is higher (39%) than in Germany or Japan. Structural shifts were accompanied by a decrease in the production of metal, but this was offset by an increase in its quality. In this regard, the role of the region in the world metallurgy has changed: for 1950-1995. Its share fell on iron ore from 43 to 16%, on coke from 41 to 8%, on cast iron from 47 to 12% and steel from 48 to 16%. The US began to reduce the production of ordinary grades of rolled metal, importing it both from neighboring countries, and from China, Europe.
The current stage of the development of the world’s ferrous metallurgy is characterized by the rapid growth of the industry in a number of countries in Asia and South America that have embarked on the path of rapid industrial development. They become powerful competitors of the countries of Western Europe, the USA.

Asia has become the leading region of the world’s ferrous metallurgy in terms of the volume of receipt of all the main products of the industry. Japan, and after it the PRC, the Republic of Korea, India and Fr. Taiwan made a powerful breakthrough in its development. In 1995, all the states of the region cumulatively provided 50% of coke in the world, almost 45% of pig iron, up to 40% of steel and rolled products. China and Japan are the world’s largest producers of ferrous metals. However, the level of development of the industry is very different in individual countries. Thus, Japan received steel per capita (800 kg in 1995) far ahead of all the large states of Western Europe and the USA. China has not reached even a low world average of 125 kg. This remains an important stimulus for the growth of the industry in China and other newly industrialized countries in Asia.

In the region there are various types of raw materials and fuels for the ferrous metallurgy. However, the degree of their security is not the same for individual countries, but for Asia as a whole. The PRC has very large resources of coking coal and a number of alloying, as well as dispersed metals. However, its iron ore is mostly of poor quality. India has deposits of rich iron ores, there are resources of coking coal and a number of alloying metals. Japan is virtually devoid of all kinds of metallurgical raw materials and fuel to ensure its metallurgy. The countries of the region can to a certain extent mutually cover their needs in these types of raw materials and fuel. However, the already achieved volumes of obtaining ferrous metals are so great that they require the attraction of the missing resources from outside.

The peculiarity of the macrostructure of metallurgy in the region is the greater role of the primary stages of the cycle (extraction of iron and alloys of alloying metals, production of coke). This is the cheapest product in the industry, which prevails in China and India. In Japan, the Republic of Korea, on about. Taiwan, based on imported raw materials and fuel, there were powerful final stages of metallurgy – steel smelting and the manufacture of rolled metal. Strong differences in the production of cast iron and steel:
In the PRC until 1995, pig iron received more than steel (this indicates the far from completed structure of the industry); In the Republic of Korea, on the contrary, steel was smelted 1.7 times more than cast iron.

The technical and technological levels of ferrous metallurgy vary greatly across the countries of the region. So, Japan already in the early 70’s. Completely stopped the open-hearth production, and the PRC in 1996 still smelted up to 15% of steel in this way. Well supplied with fuel, the world’s second largest producer of electric power, China receives only 22% of electric steel in electric furnaces, while Japan deprived of energy resources – 32%. These figures are even higher in the Republic of Korea – 38% and on about. Taiwan – 47%. Among these new producer countries, China took a special place, breaking out into the world leaders in the combustion of coke, smelting of pig iron in 1991-1993. And steel smelting in 1996. Such a new industrial country as the Republic of Korea in terms of the level of development of the industry has surpassed any of the countries of Western Europe, except for Germany. At the same time, the Republic of Korea has noticeably approached the latter on receipt of pig iron and steel and has overtaken on coke
In Eastern Europe, the CMEA member countries in the 1960s. Made the first breakthrough in the world’s ferrous metallurgy, significantly overshadowing the western regions in this industry branch. Already in 1970 the region extracted iron ore, received coke, pig iron and steel ahead of both North America and Western Europe. In subsequent years, the growth of the steel industry of Eastern Europe was even more significant. For the production of steel per capita, Czechoslovakia, Romania, the USSR and Poland were 1.5-2 times higher than France, Britain, Italy or the USA. The USSR came out on top in the world in smelting of ferrous metals, having reached the highest development index for the country in the history of the industry; In 1988 it was smelted 115 million tons of pig iron, 163 million tons of steel, 21 million tons of pipes were produced.
The transformation of Eastern Europe into the leading region of the world’s black metallurgy in terms of the volume of production of the industry was facilitated by:

1) close economic cooperation among the CMEA member countries on the basis of joint planned activities in the iron and steel industry;
2) great demand for the industry’s products in engineering, construction;
3) complete provision of the region with raw materials and fuel, primarily through their supply from the USSR, and the use of resources of each of the CMEA countries.

However, with rapid growth in the volume of production of metallurgical products, the cardinal structural transformations of the industry lagged behind. The introduction of new technology and innovative technologies lagged behind. For example, in the largest country in the region – in the USSR, steel smelting in oxygen converters in 1988 was 34% (in the USA – 58%), in electric furnaces 13% (in the USA – 37%), continuous casting of steel 17% (in the USA – 60%). In a number of Western European countries, these indicators were even higher than in the United States,

The collapse of the USSR and the CMEA led to the disintegration of the countries of Eastern Europe. This caused great damage to their metallurgy: production volumes fell several times in each of them. Thus, steelmaking in the Russian Federation (51 million tons, 1995) fell to the level of its production in the RSFSR in 1965, i.е. The country was abandoned 30 years ago. Ukraine’s steel smelting has fallen to the level of 1959. The general state of ferrous metallurgy is characterized by low utilization of production capacities (65-70%), high equipment wear (50-60%) and low profitability, which is 4-5%. This is the result of a sharp decline in investment in the industry.

Developed capitalist states restored their former leading positions in the world’s ferrous metallurgy. This was particularly noticeable in the smelting of steel and the receipt of rolled metal, i.e. The most important products of the industry.

Foreign trade in ferrous metallurgy goods. The role of the industry in global exports is small – about 3%. This is due to the low level of prices for its goods. Feature of the industry: raw materials (iron ore and alloying metals) and final products (rolling) are also exported. The role of intermediate products of metallurgy is low. In 1995, exports accounted for 45% of the world’s iron ore (400 million out of 890 million tonnes), rolled more than 20%, and cast iron only 2%. Brazil and Australia accounted for 65% of the world’s total exports of iron ore. Of the 640 million tons of manufactured rolled products in the world, about 140 million tons were exported. A wide (most often intraregional) trade exchange of different types of rolled products was formed. Excessive rentals were Eastern and Western Europe, and Asia (especially the PRC) and North America (USA) are scarce.

Methods of steel production

Conversion methods of steel production

It is customary to call a large steel retort lined with refractory. The capacity of modern converters reaches 250-400 tons. The converter has a steel cylindrical part, detachable, easily replaceable bottom and a cone-shaped neck. The cylindrical part of the converter is fixed in a cast steel ring, which has two pins, with which it rests on bearings of two racks. Therefore, the converter can rotate around the axis of the pins, which is necessary for its maintenance (casting of the original cast iron, sampling, pouring out the finished steel, etc.). One of the pins is hollow, it is connected by one air duct with a turbo-blower, and the other – with the air box of the converter’s bottom. The air box of the bottom of the converter is connected to the holes of the lances passing through the whole bottom.
Converters for the Bessemer process are lined with dinas, and for the Thomas process, dolomite.
The disadvantage of the Bessemer process is a limited gamma of cast irons, which can be processed in this way, since under the Bessemer method it is not possible to remove such impurities as sulfur and phosphorus from the metal, if they are contained in cast iron. In addition, the steel produced in the converter is brittle because of its saturation with nitrogen contained in the air.

Marten’s methods of steel production

The Martin’s method is the main way, giving about 70% of the high-grade steel smelted in the world.
The Marten method was widely used due to the possibility of using different raw materials and various fuels. At present, the open-hearth process is distinguished depending on the raw materials used: a scrap process, if its charge consists of steel scrap (60-70%) and solid pig iron (30-40%). This type of process is used in factories that do not have blast-furnace production (the Moscow plant “Serp i Molot”, etc.). Widely used and scrap-ore process, characteristic of the fact that its charge consists of 20-50% of scrap and 50-80% of liquid iron, which after the release of blast furnaces is stored in large barrel-shaped lined inside the refractory brick storage, called mixers . This process is called scrap ore, because in order to accelerate the oxidation of impurities of cast iron, in addition, hematite iron ore is charged in the amount of 15-30% of the mass of the metallic part of the charge.

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Scrap ore process in acidic and basic open-hearth furnaces passes differently (the composition of fluxes and some other charge materials varies, the impurities oxidise differently). Therefore, the acid and basic open-hearth processes are distinguished.
Free-flowing charge materials (ore, limestone, scrap) are usually loaded first, and some of their layers are warmed up well. At the bottom it is customary to first load iron ore, and then limestone and from above with steel scrap. All these materials are transported to furnaces by the composition of the platforms in so-called troughs (metal boxes with a device for grasping them with the trunk of the charging machine).
The slag of the main open-hearth furnaces obtained at the end of the process usually contains 10-15% of FeO, 9-15% of MnO, 18-25% of SiO2, 40-47% of CaO, ~ 1% of P2O5, and also of MgO, A12O3 and other oxides.
Slags, which are downloaded in the first period of melting, contain 1.5-3% P2O5; Three times more than in the slag of the terminating period, FeO; Is four times less than CaO.

The scrap process in the main furnace differs from the scrap ore process, especially during the filling and melting of the charge; The final part of the process is less.
The acidic open-hearth process is quite different. In connection with the fact that the lining of acid open-hearth furnaces is made of dinas, the welding of the hearth and slopes is carried out by quartz sand, i.e. acidic material. Slag in this furnace is acidic and does not contain free lime. Consequently, removal of sulfur and phosphorus in this furnace does not occur. Therefore, charge materials and fuel should contain these impurities in a minimum amount.
The total duration of melting of steel 220-260 tons in furnaces is usually 7-10 hours at a conventional fuel consumption of 130-150 kg per 1 ton of steel. Thus, the main disadvantages of the open-hearth process should be considered a long process time and a significant fuel consumption. That is why the direction of rationalization proposals of production teams and research of scientists – metallurgists are aimed at eliminating these shortcomings and improving the quality of the metal produced. The most important factor, improving and accelerating the open-hearth process, is the use of oxygen. In the open-hearth process there are two real and economically expedient ways of using oxygen. The first way is to enrich the air blast with oxygen to 25-35%. As a result of the intensification of combustion and increase in the oxidizing capacity of the furnace, the overall duration of melting is reduced, fuel consumption is reduced, and productivity is increased. So, for example, when enriching the blast of the furnace in 100 tons of oxygen to 29-30%, the oxygen consumption is 55-70 m3 per 1 ton of steel, the productivity of the furnace increases by 2.5 times with a reduction in the duration of melting from 9 hours to 3 hours 30 minutes; The fuel consumption is reduced from 150 kg / t of steel to 92 kg / t. Such an enrichment of the blast with oxygen and forcing the melting, possibly in the presence of a roof of a furnace made of heat-resistant refractories.
The second way is the use of oxygen to intensify the oxidation of impurities by briefly introducing oxygen into the furnace. The most promising in this direction is the introduction of oxygen by water-cooled tuyeres through the furnace arch (prior to analogy with oxygen-converter production). The introduction of oxygen in this way dramatically reduces the duration of oxidation of impurities in the furnace bath, but greatly increases (by 5-8 times) the dust content in the furnace gases, by spraying slag and evaporating the metal.

Steel production in electric furnaces

The production of steel in electric furnaces increases from year to year, since they can receive a higher temperature and a reducing or neutral atmosphere, which is very important in the smelting of high-alloy steels.
For the production of steel, the most commonly used are three-phase electric arc furnaces with vertical graphite or carbon electrodes and a non-conductive hearth. The current heating the bath in these furnaces passes through the electrode-arc-slag-metal-slag-arc-electrode circuit. The capacity of such furnaces reaches 270 tons.
The furnace consists of a metal casing of cylindrical shape and a spherical or flat bottom. The inside of the furnace is lined with refractory materials. Like open-hearth furnaces, arc furnaces can be acidic and basic. In the main furnaces, the podina is laid out of magnesite brick, on top of which a printed layer of magnesite or dolomite (150-200 mm) is made. Accordingly, in acidic kilns, use a dinas brick and a packing of quartzite on a liquid glass.
The furnace is loaded through a window (with the help of a trough and charging machine) or through a vault (using a loading bucket or a grid). In this case, the arch with the electrodes is made detachable and during the loading it is lifted, and the furnace is withdrawn to the side and by a bridge crane immediately or in two steps a full furnace cage is loaded. After this the vault is again quickly covered with a stove.
The production of steel in electric arc furnaces has undeniable advantages: high quality of steel, the ability to smelt any steel grades, including high-alloy, refractory and heat-resistant; The minimum iron burn in comparison with other steelmaking units, the minimum oxidation of expensive alloying additives due to the neutral atmosphere of the furnace, the convenience of regulating the temperature regime.
The disadvantage is: the need for a large amount of electricity and the high cost of redistribution. Therefore, electric arc furnaces are used mainly to produce highly alloyed steel grades.

Castings from cold-resistant steel

The development of cryogenic equipment, the rapid development of the raw materials base in the Far North and Far East regions, required the manufacture of machines and various equipment capable of reliably and continuously operating at negative temperatures. The cold resistance of many, including casting structural steels is not enough. The main cause causing a decrease in ductility and resistance to brittle fracture in the negative temperature range is contamination of the alloy with oxygen, sulfur, phosphorus, a number of non-ferrous metals. With their presence, the formation of various forms of nonmetallic inclusions is associated with a decrease in intercrystalline strength.

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Long-standing practice has shown that the sulfur and phosphorus concentrations (~ 0.05-0.04% of each element) allowed by the standard are extremely high. According to Yu.A. Shulte, when the sulfur content in unalloyed and low-alloy structural steels is reduced from 0.04 to 0.01%, the toughness increases by 2-3 times, the cold-brittle threshold decreases. It was found that the greatest increase in ductility and toughness is achieved with a sulfur content of less than 0.01%. Consequently, one of the directions is deep desulphurization of steel. The number of oxide inclusions and their shape are largely determined by the nature of the deoxidants and the technology for carrying out this operation. The use of silicocalcium, silicobaria, silicides for final deoxidation allows not only to reduce the overall contamination of steel with nonmetallic inclusions, but also to give them a more favorable round shape. Essential value has the structure of the metal base. The fine-grained equiaxed structure of the matrix, obtained as a result of alloying and heat treatment, increases the cold resistance of the steel.

A feature of cold-resistant casting steels is a low permissible concentration of sulfur and phosphorus (up to 0.02% each). Most of the steels are alloyed with molybdenum (0.1-0.3%) and vanadium (0.06-0.15%). The standard requires the processing of steel when melting with complex deoxidizers. Cast parts from cold-resistant wear-resistant steel are operated at temperatures up to -60 ° C.

The impact strength at -60 ° C was added to the number of delivery characteristics. Non-metallic inclusions of film type are not allowed in castings.

As follows from the above, the main features of the production of cold-resistant castings are in the smelting, modification of alloys and thermal processing of castings. No significant changes in mold manufacturing technology and other casting processes are required.

Typical representatives of castings from cold-resistant steels are links of tracks of tractors and excavators, bucket teeth, soil disintegrators, welded-cast structures of large sections of excavators; Products from these steels are mainly used in the mining and mining industry.

In refrigeration technology, liquefied gases, in particular nitrogen, are widely used. To keep it in a liquid state, you need a terrible frost – almost 200 degrees below zero. At this temperature, ordinary steel becomes brittle, like glass. Containers for storage of liquid nitrogen are made of cold-resistant steel, but for a long time it “suffered” one significant drawback: welded seams on it had a low strength. Molybdenum helped to overcome this deficiency. Previously, the composition of filler materials used in welding included chrome, which, as it turned out, led to cracking of the seam edges. Studies have allowed us to establish. That molybdenum, on the contrary, prevents the formation of cracks. After numerous experiments, the optimum additive composition was found: it should contain 20% molybdenum. And welded seams are now as easy to tolerate a 200-degree frost, just like steel itself.