Steel is one of the most important materials for almost all sectors in civil engineering, in machine and tool building and through to precision engineering. Due to the harsh process conditions and the enormous demand for raw materials and energy, the optimisation of production processes is given high priority. The product quality and reproducibility of batches are of the utmost importance as they reduce the cost of the process. Iron and steel production processes require robust measurement technology that is capable of detecting faults reliably while keeping the cost-effectiveness of the process in view.
When it comes to the right solutions for your production processes, you can rely on WIKA measurement technology.
With sintering, a mixture of fine ores, coke, recycled process materials and other aggregates is prepared, through melting, for further use in the blast furnace to ensure gas permeability for the reducing gases.
For the sintering process, the control of the sintering hood and its associated burner and the temperature in the furnace are crucial. A lost oven can result in complete process stop and fluctuating temperatures affect the quality of the product being produced.
WIKA has a portfolio of high-performance measuring instruments that are tailored to the measuring tasks of sinter plants.
In the coke plant, the coal is converted to coke by heating the prepared coal mixture batch, in the absence of air, to a temperature of 1,000 to 1,300 °C for a period of 16 to 30 hours. Coke, as a reducing agent, has a major impact on the cost-effectiveness of the process and the quality of the final product.
The quality of the coke is determined by the mixture of different types of coal. In order to achieve optimal process conditions in coke plants, the furnace pressure and the furnace temperature in the individual furnaces are monitored individually.
In the coke plant, high-precision load cells ensure a controlled mixture of the various types of coal to achieve the desired recipe composition. Our measuring instruments, which are tailored precisely to the respective requirements, guarantee a smooth processing of the vast quantities of raw materials.
Pellets are small balls of iron ore that are used in the production of steel. They are made with technology that utilises the powder that is produced during ore extraction. The process of granulation combines the blending of the raw material and a thermal treatment that burns the soft green pellets into hard balls. The raw material is rolled into a ball and then fired in a furnace or in a travelling grate to sinter the particles into a hard ball.
WIKA offers durable and high-quality process instrumentation for the production of the highest-quality pellets.
During the blast furnace process, sinter or pellets, in addition to ore, coke and lime, serve to bind the unwanted constituents of the ore in the slag and also reduce the melting temperature of the iron. They are fed from above into the blast furnace, while hot compressed air is introduced from the tuyères in the lower part. Auxiliary reducing agents or fuels – such as coal, fuel oil, natural gas or other sources – can also be injected from the bottom of the furnace.
The monitoring of fuel pressure and temperature, as well as the monitoring of blast furnace gas pressure are of utmost importance to provide normalised consumption and operating data for the process controls.
Efficient temperature monitoring enables the early detection of possible system failures. WIKA thermocouples have proven themselves to have fast and reliable temperature detection. Another challenge in blast furnace operation is the monitoring of cooling media.
Direct reduced iron (DRI), an alternative way of producing iron, has been developed to overcome the difficulties of conventional blast furnaces. DRI is successfully implemented in various parts of the world using natural gas or coal technology. On the one hand, the DRI process is very energy-efficient; on the other hand, further energy gains can be realised if the hot material is immediately transferred to an EAF melting operation (EAF = electric arc furnace). In this way, the heat from the direct reduced iron process reduces the cost of melting the DRI in the EAF, significantly reducing energy costs.
Hydrogen represents a special challenge of the DRI process. WIKA offers special pressure and temperature sensors for hydrogen applications to ensure the smooth running of the DRI process.
The pig iron produced in the blast furnace is used in the steel works in a liquid state where it is converted into crude steel in the converters. Here, the carbon contained in the pig iron is burnt by blowing in pure oxygen. An important trend in steel metallurgy is the rise in steel grades with increasing flexibility of metallurgical plants, in addition to which the further improvement of the logistics in steel works remains a permanent challenge. In steel converters, the troublesome tramp elements contained in pig iron, such as carbon, silicon, sulphur and phosphorus, are removed in the basic oxygen furnace (BOF) by blowing in oxygen. In doing this, temperatures of up to 1,700 °C are generated in the converter.
Efficient and safe cooling of the converter system is indispensable. Here, WIKA flow measuring elements combined with differential pressure transmitters are used, whereby inlet and outlet temperatures are recorded by means of temperature sensors.
Scrap-based steels are recovered in the electric arc furnace.
After loading the furnace, the melting process begins with the ignition of the arc. Using lances and/or burner systems and injectors in the furnace wall, the introduction of the oxygen and the fuel/gas mixtures takes place in order to accelerate the melting and reduce the electrical energy requirement.
Through monitoring of fuel pressure, temperature and flow values, normalised consumption and operating data are provided for the process controls. WIKA flow measuring instruments and pressure and temperature sensors perform this control task reliably and accurately.
Ladle furnaces in steel works are used in secondary metallurgy for the treatment of liquid steel. The melt is further desulphurised and adjusted to produce the steel grade desired by the customer.
The cover of the ladle furnace is usually lined with refractory materials and water-cooled. To ensure optimum operation of the ladle furnace, the exhaust duct, the electrode arms and the cabling are also cooled. For this, sufficient water pressure and the correct water inlet temperature are crucial.
Thanks to their robust measuring technology, our resistance thermometers and pressure sensors are ideal for monitoring cooling water. Pressure sensors can be installed quickly and easily due to their compact dimensions.
In the continuous casting process, the liquid steel flows from the ladle through the distributor into the moulds. The steel-filled ladle is suspended in a rotatable tower that can hold two ladles. In the casting operation, both thermal and pressure monitoring methods are used to detect local escape of liquid steel or for penetration detection.
In order to prevent the penetration, it is essential to detect the temperature profile in the casting mould so that the development of cracks can be determined. For this purpose, thermocouples are embedded in the narrow and broad sides of the mould so that they show a two-dimensional temperature profile of all sides of the mould. To determine the heat dissipation in the mould, the cooling water temperature at the cooling water inlet and outlet and also the coolant quantity are measured.
WIKA takes into account the harsh operating conditions of steel foundries with extremely robust products. They feature high resistance against shock, vibration and temperature fluctuations, high IP ingress protection and also outstanding EMC characteristics.