1. Converter steelmaking:
A steelmaking method that does not require an external heating source and mainly uses liquid pig iron as raw material. Its main feature is to rely on the physical heat of liquid pig iron in the converter and the heat generated by the chemical reaction of various components in the pig iron, such as carbon, manganese, silicon, phosphorus, etc., with the oxygen fed into the furnace as the smelting heat source to make steel. In addition to molten iron, the furnace materials also include slagging materials (lime, quartz, fluorite, etc.); in order to adjust the temperature, scrap steel and a small amount of cold pig iron and ore can also be added.
The converter is divided into alkaline (lined with magnesia or white cloud) and acidic (lined with siliceous material) according to the properties of the lining refractory material; according to the part of the gas blown into the furnace, it is divided into bottom blowing, top blowing and side blowing; According to the gas used, it is divided into air converter and oxygen converter. The acid converter cannot remove sulfur and phosphorus from pig iron, so high-quality pig iron must be used, so the scope of application is limited. The alkaline converter is suitable for steelmaking with high phosphorus pig iron and has achieved great development in Western Europe. Air-blown converter steel has not been promoted around the world because of its high nitrogen content, the limitations of the raw materials used, and the inability to use more scrap steel.
2. Oxygen top-blown converter steelmaking:
The converter steelmaking method, which uses pure oxygen to blow molten iron from the top of the converter into steel, is also called the LD method; in the United States, it is usually called the BOF method, also known as the BOP method. It is the main method of modern steelmaking. The furnace is an upright crucible-like container, with an upright water-cooled oxygen lance inserted into the furnace from the top to supply oxygen. The furnace body can be tilted.
The charge is usually molten iron, scrap steel and slag-making materials; a small amount of cold pig iron and iron ore can also be added. High-pressure pure oxygen (containing more than 99.5% O2) is blown downward from the molten pool through an oxygen lance to oxidize and remove elements such as silicon, manganese, carbon, and phosphorus in the molten iron, and dephosphorization and desulfurization are performed through slagging. The heat generated by the oxidation of various elements heats the liquid metal in the molten pool, causing the molten steel to reach the current chemical composition and temperature. It is mainly used to smelt non-alloy steel and low-alloy steel; but through refining means, it can also be used to smelt alloy steel such as stainless steel.
3. Oxygen bottom blowing converter steelmaking:
A converter steelmaking method that blows oxygen into the molten pool in the furnace through the oxygen nozzle at the bottom of the converter to smelt molten iron into steel. Its characteristics are: the height and diameter of the furnace are relatively small; the furnace bottom is flat and can be quickly disassembled and replaced; the oxygen lance system of the oxygen top-blown converter is replaced by the tuyere, distributor system and oxygen supply system on the furnace body. Due to smooth blowing, less splashing, less smoke and dust, and low iron oxide content in the slag, the metal yield of the oxygen bottom-blown converter is 1% to 2% higher than that of the oxygen top-blown converter; powdery slag-making materials are used, Due to the fine particles and large specific surface, the reaction interface is enlarged, so slag formation is rapid, which is conducive to desulfurization and dephosphorization. This method is especially suitable for blowing medium phosphorus pig iron, so it is the most widely used in Western Europe.
4. Continuous steelmaking:
A steelmaking method in which raw materials (molten iron, scrap steel) are continuously added from one end of the furnace regardless of the furnace, and the finished product (molten steel) is continuously flowed out from the other end of the furnace. The idea of continuous steelmaking process appeared as early as the 19th century. Due to the potential advantages of this process such as small equipment, simple and stable process, many countries have conducted a large number of experiments on various methods for decades, among which there are three main categories: tank method, spray method and foam method. But so far they have not been put into industrial production.
5. Mixed steelmaking:
A steelmaking method that uses one furnace to make steel and another electric furnace to make reduced slag or reduced slag and alloy, and then mix them at a certain height. Using this method to treat molten steel produced in open-hearth furnaces, converters and electric furnaces can improve the quality of steel. Flushing and mixing can increase the contact area between slag and steel, accelerate chemical reactions, deoxidation and desulfurization, and have the effect of adsorbing and polymerizing gases and inclusions, thereby improving the purity and quality of steel.
6. Compound blowing converter steelmaking:
Based on the top-blown and bottom-blown oxygen converter steelmaking methods, a new steelmaking method was developed by combining the advantages of both and overcoming the shortcomings of both. That is, different gases are blown into the bottom of the original top-blown converter to improve the melting process. Pool stir. At present, most countries in the world use this steelmaking method and have developed various types of double-blown converter steelmaking technologies. Common ones such as those developed by British Steel Company use air + N2 or Ar2 as bottom blowing gas, and use N2 as bottom blowing gas. The molten pool stirring and compound blowing converter steelmaking method with cooling gas – BSC – BAP method, developed by Klöckner – Max Metallurgical Works in Germany, uses a natural protection bottom gun to inject coal and oxygen into the molten pool from the bottom. KMS method, the K-BOP method developed by Japan’s Kawasaki Steel Company, which mixes oxygen accounting for 30% of the total oxygen content with lime powder and blows it into the molten pool from the bottom of the furnace, and the K-BOP method developed by Japan’s Kawasaki Steel Company, which mixes oxygen accounting for 30% of the total oxygen content. – 20% oxygen is blown from the bottom, and propane or natural gas is used to cool the furnace bottom nozzle LD – OB method, etc.
7. Top-blown oxygen open-hearth steelmaking:
Since the mid-1950s, a steelmaking method has been adopted in open-hearth furnace production in which 1 to 5 water-cooled oxygen lances are inserted into the melting chamber from the top of the furnace to blow oxygen directly into the molten pool. This method improves the kinetic conditions of the molten pool reaction, changes the thermal effect of the carbon-oxygen reaction from endothermic to exothermic, and improves the thermal conditions; productivity is greatly improved.
8. Electric arc furnace steelmaking:
A steelmaking method that utilizes the thermal effects of arcs to smelt metals and other materials. Three-phase AC electric arc furnaces for steelmaking are the most common direct-heated electric arc furnaces. During the steelmaking process, since there is no flammable gas in the furnace, oxidizing or reducing atmospheres and conditions can be formed according to process requirements, so it can be used to smelt high-quality non-alloy steel and alloy steel.
According to the furnace capacity per ton of the electric furnace, the electric arc furnace can be divided into ordinary power electric arc furnace, high power electric arc furnace and ultra-high power electric arc furnace. The purpose of developing electric arc furnace steelmaking towards high power and ultra-high power is to shorten smelting time, reduce power consumption, increase productivity and reduce costs. With the emergence of high-power and ultra-high-power electric furnaces, electric arc furnaces have become melters, and all refining processes are performed within the refining device. DC electric arc furnaces have developed rapidly in the past decade due to their low electrode consumption, small voltage fluctuations and low noise, and can be used to smelt high-quality steel and ferroalloys.
9. STB method:
The original text is Sumitomo Top and Bottom blowing process, a top-bottom combined blowing converter steelmaking method developed by Sumitomo Metal Corporation of Japan. This method combines the advantages of the oxygen top-blown converter steelmaking method and the oxygen bottom-blown converter steelmaking method. Used for blowing low carbon steel, it has good dephosphorization effect and significant cost reduction. The bottom blowing gas used is O2, CO2, N2, etc. Based on the STB method, the STB-P method of injecting powder from the top was developed, which further improved the dephosphorization conditions of high carbon steel and was used to refine stainless steel.
10. RH method:
Also known as cycle vacuum treatment. Jointly developed by the German Ruhrstahl/Heraeus company. There are two conduits installed at the bottom of the vacuum chamber, into which the molten steel is inserted. After the vacuum is evacuated, the molten steel rises to a certain height, and then the inert gas Ar is blown into the rising tube. Ar rises and drives the molten steel into the vacuum chamber for vacuum treatment, and then flows back through another conduit. ladle. The vacuum chamber is equipped with an alloy feeding system. This method has become the main vacuum treatment method for molten steel in large-capacity ladles (>80t).
11. RH—OB:
RH oxygen blowing method. It is to add oxygen blowing operation (Oxygen Blowing) to the vacuum cycle degassing (RH) method to raise the temperature. When used for refining stainless steel, the decarburization reaction can be prioritized under reduced pressure; when used for refining ordinary steel, the load on the converter can be reduced. Adding aluminum can also be used to raise the temperature.
12. OBM-S method:
The original text is Oxygen Bottom Maxhutte—Scarp, an oxygen bottom-blown converter steelmaking method invented by the German Maxhutte-Klockner factory that uses natural gas or propane as the bottom-blown oxygen lance cooling medium. OBM-S installs a side-blown oxygen lance on the furnace cap of the OBM oxygen bottom-blown converter, and the bottom oxygen lance blows coal gas and natural gas to preheat scrap steel, thereby achieving the purpose of increasing the scrap-steel ratio.
13. NK-CB method:
The original text is NKK Combined Blowing System, a top-bottom combined blowing converter steelmaking method established by Japan Steel Pipe Company in 1973. That is, while top blowing, a small amount of gas (Ar, CO2, N2) is blown from the bottom of the furnace to strengthen the steel slag. Stir and control the CO partial pressure in the molten steel. This method uses porous brick nozzles, which can reduce costs when used to make low-carbon steel; and is beneficial to dephosphorization when used to make high-carbon steel. This method should be combined with the molten iron pretreatment process.
14. MVOD:
A water-cooled oxygen lance is added to the VAD method equipment so that it can blow oxygen for decarburization under vacuum. Since decarburization under vacuum is an exothermic reaction, the vacuum heating measures of the VAD method can be omitted. The operation process is the same as the VOD method.
15. LF method:
The original text is Ladle Furnace, which is a ladle furnace refining method developed by Japan Special Steel Company (Dado Steel Special Steel Company) in 1971. Its equipment and process are composed of argon stirring, submerged arc heating and alloy feeding systems. The advantages of this process are: it can accurately control the chemical composition and temperature of molten steel; it reduces inclusion content; and it has a high yield of alloying elements. LF furnace has become an indispensable external refining equipment between steel-making furnace and continuous casting machine.
16. LD steelmaking method:
In 1952, the Linz plant of Voestalpine and the Donawitz plant of the Austrian Alpine Mining and Metallurgical Company were the first to successfully develop the oxygen top-blown converter steelmaking method in industry, and named them after the first letters of the two plants. And named. After the advent of this law, it was rapidly promoted around the world. The United States calls this method the BOF or BOP method, which is the abbreviation of Basic Oxygen Furnace or Process. See oxygen top blowing, converter for details.
17. LD-OTB method:
The original text is LD—Oxgyen Top an Bottom Process, a top-bottom composite blowing converter steelmaking process developed by the Kakogawa Plant of Kobe Steel Corporation in Japan. Its characteristic is the use of a special bottom-blowing single-ring slit nozzle (SA nozzle), so the bottom-blowing gas can be controlled within a wide range. Inert gas is blown into the bottom.
18. LD-HC method:
The original text is LD—Hainaut Saubre CRM, which is a top-bottom combined blowing converter steelmaking method developed in Belgium for blowing high-phosphorus molten iron, that is, LD+bottom blowing oxygen, and using hydrocarbons to protect the nozzles.
19. LD-AC method:
The original text is LD – Arbed – Center National. It is a top-blown oxygen-injection lime powder steelmaking method developed by the French Iron and Steel Institute, which is used to blow high-phosphorus molten iron.
20. KS method:
The original text is Klockner Steelmaking, which is a bottom-coal-injection pulverized oxygen converter steelmaking process operated with 100% solid materials. The bottom blowing oxygen ratio is 60% to 100%.
21. K-ES method:
The electric arc furnace steelmaking method combines bottom blowing gas technology, secondary combustion technology and pulverized coal injection technology. It is a technology jointly developed by Tokyo Steelmaking Company of Japan and Kiokner Company of Germany, which can replace electricity with coal.
22. FINKL-VAD method:
Arc heating ladle degassing method or vacuum arc degassing method. Its characteristic is that an arc heating device is added to the cover of the vacuum chamber and it is stirred with argon gas under vacuum. The degassing effect of this method is stable, and it can desulfurize, decarburize and add a large amount of alloys. The equipment mainly consists of a vacuum chamber, arc heating system, alloy feeding device, vacuum system and hydraulic system.
23. DH method:
A vacuum processing device developed by the German Dortmund Horder United Metallurgical Company. A vacuum chamber lined with refractory materials, with a refractory-lined conduit at the lower part inserted into the ladle. The vacuum chamber or ladle is lowered and lifted periodically, allowing a portion of the molten steel to enter the vacuum chamber and return to the ladle after treatment. The upper part has an alloy adding device and a vacuum heating and heat preservation device. This equipment is no longer built.
24. CLU method:
A method of refining stainless steel. The principle is the same as the AOD method, but water vapor is used instead of argon as the object point. This method was successfully developed by the French company Creusot-Loire and the Swedish company Uddeholm, and was officially put into production in 1973. Water vapor decomposes into H2 and O2 after contact with molten steel; H2 reduces the CO partial pressure. At the same time, this decomposition reaction is an endothermic reaction, so it can suppress the temperature rise of the molten steel. However, the oxidation and burning loss of chromium is more serious than that of the AOD method.
25. CAS method:
The original text is Composition adjustment by sealed argonbubbling, which is an out-of-furnace refining method for fine-tuning alloy composition under argon sealing. In this method, argon is blown from the bottom of the ladle. After the slag is discharged, the impregnation hood is lowered, argon is continued to be blown, and then alloy is added to fine-tune the composition. The advantage is that the composition can be precisely controlled and the alloy yield is high.
26. CAS-OB method:
The original text is Compositon adjustment by sealed argon bubbling with oxygen blowing, which is an out-of-furnace refining method that adds an oxygen blowing gun to the CAS equipment. In addition to fine-tuning the alloy composition, it can also add aluminum and blow oxygen to raise the temperature (chemical thermal method). The heating rate is 5 to 13°C/min. This method can accurately control the temperature of molten steel at ±3°C, which is beneficial to continuous casting production.
27. ASEA-SKF method:
A ladle refining method developed in Sweden. It uses low-frequency electromagnetic stirring, arc heating under normal pressure, slagging and refining in the ladle, vacuum degassing at another station, and is equipped with an oxygen lance to blow oxygen for decarburization under reduced pressure. In order to improve the refining effect, it can also blow argon through porous bricks at the bottom of the ladle to stir, and alloy can be added to adjust the composition of the molten steel.
28. AOD method:
Argon-Oxygen decarburization method and abbreviation, the original text is Argon-Oxygen Decarburisation, is the main refining method for smelting low-carbon stainless steel. It was successfully developed by the American Carbide Company in 1964 and used in actual production in 1968. The metallurgical principle is to dilute CO with Ar to reduce its partial pressure and achieve a vacuum effect, thereby decarbonizing to a very low level. The AOD furnace body and transmission device are similar to those of a converter. The wind eye is placed on the side wall close to the bottom of the furnace. Ar+O2 mixed gas is blown into the furnace. The raw material is molten steel melted in the primary furnace. The blowing process is divided into oxidation period, reduction period and refining period. It has become the main production process of stainless steel.
