A billet is one of the medium-rolled steel products with a cross-sectional area of less than 230 square millimeters. The cross-section of this product is round or square with a width of less than 15 cm. Steel blocks are mainly used for the production of steel bars and wire rods. Billets are one of the types of ingots that produce different sizes and dimensions. The billet is used to produce some steel products such as beams and rods. Billet ingot is one of the most important steel products and comes in different grades. In fact, billets are products of steel mills and belong to the category of intermediate products. Billet Billet ingot or billet is one of the products made from iron ore, which itself is the raw material for making many other steel products. After iron ore is converted into steel, it must be produced in various forms, each with unique physical and chemical properties. Forms of different types of steel:
- ingot
- slab
- bloom
- billet
They are produced in factories and sent to the market. Each of these products is suitable for the manufacture of certain goods, so there are differences in their chemical composition and size and shape . Steel ingots are usually produced in relatively small widths, and products made with it are also smaller in cross-section and width, but longer products are produced with it due to the special chemical composition of the ingot. In terms of consumption and use, billet can be considered the most widespread type of bar. This semi-finished steel product is converted into other finished products in various processes. How to make billetsThere are two general methods of making this product, the first method is the blast furnace method and the second method is the electric arc method. In both methods, the excess material must be separated from the iron ore, and the pure iron is extracted, melted and poured into molds and delivered as ingots. The difference between these methods is the method of melting the iron, the other steps are almost the same. In the following, we will examine the two main methods of producing different types of ingots. Almost most of the ingots produced are produced by the above method, but in a few cases different types of ingots can be produced by extrusion or rolling. The types of ingots produced may vary slightly in properties such as twisting, stretching or bending, and each billet mill may have specific chemical analyzes for the product.
- Blast furnace production method
The biggest billet production is the blast furnace method. In this method, we first need iron ore. There is no doubt that this iron ore has impurities that must be separated from it.
Therefore, in the first step, iron ore must be prepared so that the iron in it can be separated from other elements. To produce iron ore, pre-roasting and agglomeration steps must be carried out. In the next quarter, lime and coke are added and poured into the blast furnace, and the result of this process is cast iron or pig iron. This material is then poured into a converter and melted. Oxygen is then supplied to the molten iron so that its impurities combine with the oxygen and are separated from it as slag. In the next section, pure molten iron will be poured into a large container called a cauldron and sent to the forming section. Arc production methodIn the arc method, we need scrap iron raw material. The scrap iron is first put into the electric furnace, and then lime, coke, bentonite, and other slag materials are added, and some sponge iron also enters the furnace. These materials are melted in an electric furnace, during which operational steps such as oxygen blasting, homogenization, sampling, and analysis must be carried out. In the next step, this pure molten iron enters the pot and enters the casting unit. In this unit, molten material is poured into a mold, which is then cooled with water. After the ingot has cooled, the parts are cut to the desired size. Components of a ticketTickets typically have a circular, square or octagonal cross-section. The diameter or width of the ingot is usually less than 15 cm and its cross-sectional area is less than 23 cm². Due to its special texture, billets are denser than other types of ingots and have relatively high flexibility. The material of the billet has a special type of grain which makes this material very flexible and also has the possibility of being very malleable.
During the production stage of this product, care must be taken to ensure that all processes are carried out in accordance with standard details, otherwise, the strength and flexibility of the raw material will not be suitable for the market. In order to maintain the quality of the product, the ingot must be tested for temperature changes in the final step, so that the metal does not crack or crack during heating and cooling, as such a product would not be suitable for the production of downstream products. In the chemical composition of this product, different elements are responsible for different mechanical, physical, and chemical properties, including:
- NiobiumIncrease wear resistance
- CobaltIncrease the heat resistance of metals
- TungstenIncrease wear resistance
- SiliconIncrease strength and toughness
- VanadiumA finer microstructure of the steel
- ManganeseImprove the ability to work deeply and hard
- NickelIncrease toughness and wear resistance
- ChromeIncrease toughness and wear resistance
- Phosphorus, lead, sulfur, calciumImprove processing capacity
- MolybdenumImprove heat resistance and improve hardenability
There are a few types of billets that are used directly, and in most cases, billets must be processed and new products made from them.
steel production line in major companies
Major companies work and have separated steel production lines and Our company's mission is to play a central role in the national industrial, economic and social development and to improve the technical level of the iron and steel industry. produces heavy and liquid transport pipes, the packaging industry, the household appliance industry, and the pipe and profile industry. Steel is one of the most used metals in the modern world. The metal is cheap, strong, and versatile. Steel is the world's second most mass-produced raw material after cement, with an annual production of around 750 million tons. Steel is fully recyclable and requires relatively low energy consumption to produce it. Iron is the fourth most abundant element on Earth and makes up more than 5% of the Earth's crust. Human iron production began around 2000 BC. in the southwest or south-central Asia. This period can be called the beginning of the Iron Age, which led to the widespread use of iron instead of bronze for the manufacture of tools and weapons. During this time, blacksmiths transformed impure iron into mature iron by heating and hammering. The resulting iron is hard but malleable. During the Middle Ages, a new type of iron was developed that was produced at higher temperatures. This new type of iron, called cast iron, is harder but more brittle than wrought iron. With the advent and mass production of steel in 1870, steel replaced iron.
steel composition
Steel is an alloy of iron and carbon and may contain small amounts of silicon, phosphorus, sulfur and oxygen. Steel has a carbon content between 0.08% and 1.5%, making it harder than wrought iron but not as brittle as cast iron. Steel has a unique balance between hardness, flexibility, and tensile strength. Steel is more durable than iron and has a higher resistance to shock and stress than brittle cast iron. The following examples are the main uses of steel:
- railways
- Oil and gas pipelines
- skyscraper
- elevator
- subway
- bridge
- build cars and ships
- Cutlery and fork
- Blades and surgical instruments
To make steel, iron ore is heated in special furnaces to remove impurities, then carbon is added. Today, steel is made in one of two ways: blast furnace EAF electric arc furnace The first method mainly uses raw materials (such as iron ore, limestone, coking coal) to produce steel along with some scrap steel; while the second method mainly uses scrap to make steel. blast furnace The blast furnace was invented in the mid-1850s by an Englishman named Henry Bessemer. In this method, steel production is done by blowing air through molten iron and oxidizing and separating impurities. Today's blast furnaces are long steel drums lined with refractory bricks. Iron ore, coking coal, and limestone enter the hearth from the top and gradually move downwards; the lower they are, the hotter they are. In the upper half of the furnace, gases from burning coking coal release the oxygen in the iron ore. In the lower half of the furnace, the limestone begins to react with impurities in the iron ore and coking coal, creating a mixture of impurities called "slag".
At the bottom of the furnace, the temperature reached over 3,000 degrees Fahrenheit. The slag, which contains impurities, floats on top of the molten steel and is discharged through slits in the furnace. The molten steel is discharged through a hole in the furnace core. Electric arc furnace This method is mainly used for the production of special steels alloyed with other metals. These furnaces are of course also used for the production of ordinary and unalloyed steel. Unlike blast furnaces, electric arc furnaces do not use molten iron. Instead, they use scrap steel extracted from recycled products. Scrap is transferred to the arc furnace with overhead cranes. When the oven is full, the door closes and covers the top of the oven. Electrodes are embedded in the door into the oven. These electrodes carry a strong current that generates heat and melts the scrap. By melting scrap steel, other metals called ferroalloys are added to the steel to create the desired chemical composition of the steel. To refine the steel, oxygen is blown into the furnace. Lime and fluorite, a mineral compound, are also added to combine with impurities to form slag. Raw material storage and collection unitThe main task of the stacking and harvesting unit is to homogenize and mix the material, create suitable storage space, and make the pelletizing and. regeneration unit independent of each other according to the design of 4.5 million tons of raw materials, including iron ore fines and pelletizing per year has now reached 6.5 million tons of unloading capacity. In addition, up to 2 million tons of iron ore powder and pellets can be stored in the unit. The majority of iron ore veneers consumed are supplied by wagons in domestic mines; incoming wagons are weighed by rail scales and then enter the return wagon area for unloading. The act of moving the car towards the guide car and adjusting its position inside the guide car can be performed by a car indexer or a locomotive. The trucks are unloaded from the tipper one by one and transported to the storage area (parking lot) through the vibrating feeder and conveyor belt. The empty weight is 30 tons, and the current load in each vehicle is 90 tons, which can be increased to 120 tons.
Three parks with a length of 750 meters and a width of 38 meters are specially used for the accumulation and mixing of iron ore powder, and three parks with a length of 950 meters and a width of 47 meters are specially used for the accumulation and mixing of iron ore powder. particles. The stacking task is performed by three accumulators and the harvesting task is performed by three combines. The unloading capacity of the stacker and associated conveyors is 2800 t/h, and the harvesting capacity of the harvester and associated conveyors is 1500 t/h of fine iron ore and 1000 t/h pellets. Pelletizing unitIn the pelletizing unit, 95% of the coarse iron ore particle size is below 1mm after entering the pelletizing machine, and 75%~80% is below 45 microns. Next, the milled iron ore is mixed with 80% to 85% fine iron ore below 45 microns, bentonite (as glue), and moisture, which is prepared and fed to green pelletizing pans. In pellet mills, the iron ore mixture is converted into green pellets with a size of 5 to 25 mm. After the green pellets are ground by a roller mill, the pellets with a size of 8-16 mm enter the baking oven. In the kiln, the green pellets go through stages of drying, preheating, baking, and cooling to a strength suitable for use in the direct regeneration process and then leave the kiln. The produced oxide particles are then sent to a direct regeneration unit for consumption or to an accumulation and harvesting unit for accumulation.