In the iron and steel smelting process, due to improper ingredients or improper loading and excessive decarburization, the carbon content in steel or iron sometimes fails to meet the expected requirements, and carbon is added to steel or molten iron. The main substances commonly used for carbon addition are anthracite powder, carbon-increasing pig iron, electrode powder, petroleum coke powder, pitch coke, charcoal powder and coke powder. The requirement for recarburizer is that the higher the fixed carbon content, the better, and the lower the content of harmful impurities such as ash, volatile matter and sulfur, the better, so as not to contaminate the steel.
The smelting of castings uses high-quality recarburizer after high-temperature burning of petroleum coke with little impurities. It is also the calcined coke that I often say, which is the most important part of the carbon-increasing process. The quality of the recarburizer determines the quality of the molten iron and determines whether it can achieve good graphitization. In short, reducing the shrinkage of the molten iron recarburizer plays a pivotal role.
In the smelting of the whole scrap electric furnace, the graphitized recarburizer is preferred. After the high-temperature graphitization of the rebcarurizer, the carbon atoms can be changed from the original disordered arrangement to the sheet-like arrangement, and the flake graphite can become the best of the graphite nucleus. The core is to promote graphitization. Therefore, in pursuit of high quality requirements, we should use a high-temperature graphitized recarburizer. Because of the high temperature graphitization treatment, sulfur is reduced by the generation of S02 gas. Therefore, the graphitized rebcarburizer has a very low sulfur content, w(s) is generally less than 0.05%, and better w(s) is even less than 0.03%. At the same time, this is also an indirect indicator of whether or not high temperature graphitization and graphitization are good. If the selected recarburizer is not subjected to high temperature graphitization, the nucleation ability of graphite is greatly reduced, the graphitization ability is weakened, and even if the same amount of carbon can be achieved, the result is completely different.
The so-called rebcarurizer is to increase the carbon content in the molten iron after the addition, so the fixed carbon content of the recarburizer must not be too low, otherwise it is necessary to add more than the high-carb recarburizer to achieve a certain carbon content. The sample, which undoubtedly increases the amount of other unfavorable elements in the recarburizer, does not allow the molten iron to obtain better yields.
The low content of sulfur, nitrogen and hydrogen is the key to prevent the formation of nitrogen pores in the casting, so that the lower the nitrogen content of the recarburizer, the better. Other indicators of recarburizer, such as the lower the amount of moisture, ash, and volatile matter, the higher the fixed amount of damage, so the high fixed carbon content, the content of these harmful components must not be high. It is also important to select the appropriate recarburizer particle size for different melting methods, furnace types and size of the melting furnace. It can effectively increase the absorption rate and absorption rate of the recarburizer by the molten iron, and avoid the increase due to too small particle size. The agent is oxidized and burned. The particle size is preferably: 100 kg furnace is less than 10 mm, 500 kg furnace is less than 15 mm, 1.5 ton furnace is less than 20 mm, and 20 ton furnace is less than 30 mm. In converter smelting, when high carbon steel is used, a recarburizer containing little impurities is used.
The requirement for recarburizer for top-blown converter steelmaking is that the fixed carbon is high, the ash, volatiles and sulfur, phosphorus, nitrogen and other impurities are low, dry, clean and moderately sized. Its fixed carbon C>97%, volatile matter <1.0%, S<0.5%, moisture <0.5%, particle size in l-5mm. The particle size is too fine to be easily burned, and when it is too thick, it floats on the surface of the molten steel and is not easily absorbed by the molten steel. For the induction furnace, the particle size is 0.2-6mm, wherein the steel and other ferrous metals have a particle size of 1.4-9.5mm, the high carbon steel requires low nitrogen, the particle size is 0.5-5mm, etc., and the specific need to smelt the workpiece according to the specific furnace type. The specific types and details of the specific judgment and selection.
Cast iron carburizing agent is a kind of additive for steelmaking, which can greatly increase the amount of scrap steel, reduce the dosage of pig iron or do not use pig iron. The use of calcined petroleum coke in steelmaking can not only reduce the use of pig iron, but also increase the utilization of scrap steel. Carburizing agent is an essential carbon addition material for producing high quality steel. Different types of cast iron are selected, and different types of carburizing agents are selected according to needs.
At present, the vast majority of recarburizer are suitable for electric furnace melting, and some of the fast absorption carburizing agents are used in cupola. The feeding way of electric furnace smelting should be carburized with the burden of steel and other materials. The small dosage can be added to the surface of molten iron. However, it is necessary to avoid bulk feeding into molten iron to prevent excessive oxidation. The amount of calcined petroleum coke is determined according to the ratio of other raw materials and carbon content. The characteristics of carburizing agent itself choose pure carbon graphitized material, reduce too much impurity in pig iron, and the selection of carburizing agent can reduce the cost of casting production.
The requirement of recarburizer for foundry steelmaking is high carbon content, high carbon content, low sulfur content, stable carburizing effect and high carbon absorption rate. It can be used in various electric furnaces to smelt cast steel and cast iron, and bring considerable economic benefits to production. But do you know what kind of carburizing agent is good carburizing agent? First, the appearance of the carburizer, clean and impurity-free.
Steelmaking recarburizer for casting, cast iron, cast steel, cast will have a requirement for carbon, then recarburizer just as its name implies is to increase the carbon content in liquid iron, and, for example, commonly used in smelting furnace charge for pig iron, scrap steel, back to the furnace charge, iron carbon content is high, but relatively scrap purchase price is higher section, so adding scrap supply, reduce the quantity of pig iron, add recarburizer, can have certain effect to reduce the casting cost.
Below by yu da energy conservation for you to introduce.
In the process of smelting, the carbon content of steel does not meet the requirements of the top period due to improper mixing or charging and excessive decarbonization, etc. At this time, carbon is added to the steel solution.
Common carbon - increasing agents are carbon - increasing pig iron, electrode powder, petroleum coke powder, charcoal powder and coke powder.In converter smelting, high - carbon steel, the use of oil coke containing few impurities as a carbonizing agent.
The requirements for the top blown converter steelmaking use of the carburizer are high fixed carbon, low ash, volatile and sulfur, phosphorus, nitrogen and other impurities, and dry, clean, moderate particle size.
Recarburizer is suitable for smelting in induction furnace, but its application is different according to the technical requirements.
(1) in the smelting process of medium-frequency electric furnace, the use of carbon intensifier can be added to the lower part of the furnace with the material in accordance with the requirements of proportion or carbon equivalent, and the recovery rate can reach more than 95%;
(2) if the lack of carbon adjustment, the first dozen net furnace slag, plus carburant, by raising the temperature of molten iron, or artificial electromagnetic stirring to dissolve carbon absorption, the recovery rate is around 90%, if the low-temperature carbonization process, the melt furnace charge only part of the molten iron liquid under the condition of low temperature, all recarburizer one-time in liquid iron, at the same time with solid charge to press it into the liquid iron don't let it show liquid iron surface.
This method can increase the carbon content of iron liquid by more than 1.0%.
Graphitized Petroleum Coke 0-3mm Recarburizer
Date: July 17, 2018
Volatile Matter: 0.73%
Fixed Carbon: 98.39%
Graphitized Petroleum Coke(GPC) is made from high quality petroleum coke under a temperature of 2,500-3,500°C. As a high-purity carbon material, it has characteristics of high fixed carbon content, low sulfur, low ash, low porosity etc.It can be used as carbon raiser ( Recarburizer ) to produce high quality steel, cast iron and alloy.It can also be used in plastic and rubber as an additive.
Recarburizer for steel making and carbon adding agent for cast iron, as well as some other adding materials are also useful to the carbon adding agent, and the recarburizer belongs to the external steelmaking, iron making and carbon adding material. High quality recarburizer is an essential auxiliary additive for the production of high quality steel products. However, due to various reasons of the market, the supply of carburizing agents is in short supply, and the price is rising. Many buyers can not buy the spot goods, and the suppliers also seize the opportunity to hoard goods and rob them. So what is the reason why carbon carburization is hard to get?
A. The price of pig iron remains high, and scrap iron takes the place of pig iron.
From the price of raw materials, because of the abundant supply of waste steel in the developed countries, the waste steel in China has been deposited more in the society and the price of scrap steel is much lower than the price of raw iron. So in these years, the waste steel and carbon adding agent have been widely used to produce cast iron, that is, "synthetic cast iron". In the process of production, if the process is correct, not only the chemical composition and temperature of the cast iron are easy to be controlled, but also the comprehensive physical properties of the castings can be improved and the production cost of the castings can be reduced. In the process of continuous development and continuous improvement of synthetic cast iron technology, the amount of waste steel added more and more, from the initial small amount of addition, it has now increased to 80%, so the scrap steel has replaced the high price raw iron raw material.
B. As the amount of scrap increases, the recarburizer is in short supply.
EAF melting iron is not a carbon source as cupola. In order to get the qualified carbon content, adding recarburizer is an essential measure. When recarburizer is used in casting, it can greatly increase the amount of scrap steel, reduce the dosage of pig iron or do not use pig iron. Thus, the production cost of the foundry enterprises is greatly reduced, and the carburant has gradually become one of the required materials for the foundry enterprises, and the resources of the market recarburizer are particularly tense, and a short supply will appear for a long time.
In recent years, more and more factories use the induction electric furnace for cast iron, but usually only the metal material can not keep the carbon content in iron, so that's why it need the recarburizer. For the induction electric furnace, special the intermediate frequency furnace, adding the carbon material is important link for smelting.
1. Shoul choose the carbon additive(calcined petroleum coke) with low nitrogen
The usual nitrogen content in cast iron liquid is below 100 ppm. If the nitrogen content exceeds this concentration (150-200 ppm or higher), it is easy to cause cracks, shrinkage or loose defects in the casting, and thick-walled castings are more likely to occur. This is caused by an increase in the amount of recarburizer added when the proportion of scrap steel increases. Coke-based recarburants, especially bitumen coke, contain large amounts of nitrogen. The graphite graphite has a nitrogen mass fraction of 0.1% or less or a very small amount, and the pitch pyrolysis mass fraction is about 0.6%. If 2% of the recarburizer with a mass fraction of 0.6% nitrogen is added, this increases the nitrogen content by 120 ppm. A large amount of nitrogen is not only liable to cause casting defects, but also nitrogen can promote pearlite compaction, ferrite hardening, and strongly increase strength.
2. Ways to adding the recarburizer
The stirring of molten iron can promote carbon addition. Therefore, the medium frequency induction electric furnace with weak stirring force is much more difficult to increase carbon than the power frequency induction electric furnace with strong stirring power. Therefore, the medium frequency induction electric furnace has the carbonization speed and the melting rate of the metal charge The possibility.
Even in a power-frequency induction furnace with high stirring power, the carbon-increasing operation cannot be ignored. This is because, from the schematic diagram of the induction furnace melting, there is a stirring iron flow separated vertically in the induction furnace, and there is a dead angle near the furnace wall at the boundary. The graphite cluster which stays on the furnace wall and adheres cannot be melted into the molten iron without excessive temperature rise and long-term iron liquid heat preservation. Excessive heating of the molten iron and long-term heat preservation will increase the degree of supercooling of the molten iron and increase the tendency of the cast iron to become white. In addition, for medium frequency induction furnaces that generate a strong induced current near the furnace wall, if molten iron is drilled between the graphite clusters attached to the furnace wall, the drilled metal is melted during the next furnace smelting, resulting in erosion. And damage the furnace wall. Therefore, in the case where the proportion of scrap steel is high and the amount of recarburizing agent is added, it is necessary to pay more attention to the addition of the recarburizing agent.
The addition time of the recarburizer cannot be ignored. If the addition time of the recarburizing agent is too early, it is easy to adhere to the vicinity of the bottom of the furnace, and the recarburizing agent adhering to the furnace wall is not easily melted into the molten iron. On the contrary, if the joining time is too late, the timing of carbon increase will be lost, causing the smelting and heating time to be slow. This not only delays the time of chemical composition analysis and adjustment, but also may cause harm due to excessive temperature rise. Therefore, the recarburizing agent is preferably added little by little during the process of adding the metal charge.
The recarburizer contains: fixed carbon, moisture, ash, volatile matter, sulfur, nitrogen, and so on. Different types of recarburizers with certain different content.
Calcined petroleum coke recarburizer is widely used in many industries. Calcined petroleum coke recarburizer can be used in steel making, iron making, ordinary casting and other industries; calcined petroleum coke recarburizer can also be used to make brake discs on casting, Crankshaft, brake pads, etc.
Graphitized petroleum coke also widely used in industry for metallurgy, casting, precision casting as a recarburizer, for the production of high temperature smelting, lubricants for the mechanical industry, making electrodes and pencil lead, widely used Advanced refractory materials and coatings for the metallurgical industry, stabilizers for military industrial pyrotechnic materials, pencil cores for light industry, carbon brushes for the electrical industry, electrodes for the battery industry, catalysts for fertilizer industries, etc.
If you want to know the price of items above or any questions about the products ,please feel free to contact me via below information:
Contact: Owen Zhang
Mobile： +86 182 1805 1155
Wechat: 182 1805 1155
Whatsapp: +86 182 1805 1155
Add: Room 329,Zinji City building, Xiaxi, Guicheng, Nanhai, Foshan, Guangdong, China
The high-quality recarburizer generally refers to the process of graphitization after high-temperature treatment. Under the high temperature condition of 3000 °C, the carbon molecular form changes from an irregular arrangement to a hexagonal uniform arrangement. This graphite structure is most easily decomposed in molten iron and steel.
Mainly used to increase the carbon content for metallurgical steelmaking and ductile iron casting.
1) The low-sulfur graphitization recarburizer has a high decomposition rate and a high absorption rate, and can reach more than 90%.
2) High carbon, low sulfur, low nitrogen, and extremely harmful components.
3) Adding graphite nucleus to molten steel and molten iron, more uniform and finer distribution in molten steel and molten iron, so that the performance is more excellent and stable.
The graphitized recarburizer is suitable for melting in an induction furnace, but it is not the same depending on the process requirements.
(1) Use low-sulfur graphitization recarburizer in medium-frequency electric furnace smelting, which can be added to the lower part of electric furnace at one time or two to three times according to the ratio or carbon equivalent requirement, and the recovery rate can reach more than 90%;
(2) If the amount of carbon is insufficient to adjust the carbon content, firstly clean the slag in the furnace, add the recarburizer, and heat the iron by electromagnetic stirring or electromagnetic stirring.
(3) Use graphitized recarburizer when tapping, put the recarburizer into the bag, or flush with the flow from the tapping trough, stir well after the molten iron, dissolve and absorb carbon as much as possible, carbon The recovery rate is around 90%.
Usually packing in 25kg/bag, 30Kg/bag or with jumboo bag, and also can be packaged according to customer requirements.
Calcined Petroleum Coke 1-10mm
Date: December 05, 2015
Volatile Matter: 0.74%
Fixed Carbon: 98.55%
High calorific power: 32.8 MJ/KG
Low calorific power: 32.78MJ/KG
The so-called recarburizer is to increase the content of carbon in the molten iron after it is added. Therefore, the fixed carbon content of the recarburizer must not be too low. Otherwise, to reach a certain carbon content, it is necessary to add a high carbon content. With more samples of recarburizer, this undoubtedly increases the amount of other unfavorable elements in the recarburizer, so that the ferrofluid can not obtain a better return.
Low levels of sulfur, nitrogen, and hydrogen are key to preventing the production of nitrogen holes in castings. This requires that the nitrogen content of the recharging agent be as low as possible. The other indicators of recarburizers, such as moisture, ash, and volatiles, the higher the amount of fixed breakage, so the high fixed carbon content of these harmful ingredients must not be high. For different smelting methods, furnace types, and sizes of smelting furnaces, it is also important to select an appropriate particle size of the carbon reductant, which can effectively increase the absorption rate and absorption rate of the recarburizer by the molten iron and avoid excessively small particles. Caused by oxidative damage to the breaker. The particle size is preferably: 100 kg furnace less than 10 mm, 500 kg furnace less than 15 mm, 1.5 tons furnace less than 20 mm, 20 tons furnace less than 30 mm. In the smelting of converters, when high-carbon steels are used, recarburizers containing little impurities are used.
The requirement for the recarburizer for top-blowing converter steelmaking is that the fixed carbon should be high, the content of ash, volatile matter and sulfur, phosphorus, nitrogen and other impurities should be low, and it should be dry, clean, and the grain size should be moderate. Its fixed carbon C> 97%, volatile matter <1.0%, S <0.5%, moisture <0.5%, particle size in l-5mm. The particle size is too fine to be easily burned, and it is too thick to float on the surface of the molten steel and is not easily absorbed by molten steel. The particle size of the induction furnace is 0.2-6mm, in which the steel and other ferrous metals have a particle size of 1.4-9.5mm, the high carbon steel requires low nitrogen, the particle size is 0.5-5mm, etc. The concrete need to be based on the specific furnace type smelting workpiece The details of the types and so on are specifically judged and selected.
Name: Owen Zhang
Mobile： 0086-182 1805 1155
Wechat: 182 1805 1155
Whatsapp: 0086-182 1805 1155
Add: Foshan, Guangdong, China