(Carbon steel industry in the People's Republic of China standard, YB / T 192-2001 carbon steel with Carburant) and cast iron with Carburant, and some other materials are also useful to increase the Carburant, such as brake Sheet with additives, for friction materials. Carbonizers are added to steel, iron and carbon by carbon raw materials. High-quality Carburant is essential for the production of high-quality steel auxiliary additives.
There are many kinds of raw materials for the addition of carbon, the production process is also different, there are wood carbon, coal carbon, coke, graphite, etc., which under the various categories and a lot of small species. High-quality Carburant generally refers to the graphite by the Carburant, in high temperature conditions, the arrangement of carbon atoms in the micro-morphology of graphite, so called graphitization. Graphitization can reduce the amount of impurities in the Carburant, increase the carbon content of the Carburant, reduce the sulfur content.
The use of carbonizers in the casting can significantly increase the amount of scrap, reduce the amount of pig iron or no pig iron. Electric furnace smelting of the feeding method, the Carburant should be with the scrap and other materials into the inside together, the addition of small doses can be added to the surface of the molten iron. But to avoid large quantities of molten iron to feed, to prevent excessive oxidation and the effect of carbon is not obvious and the cast carbon content is not enough. The amount of Carburant added, according to the ratio of other raw materials and carbon content to be set. Different types of cast iron, according to the need to choose different types of Carburant. The characteristics of the Carburant itself choose pure carbon-containing graphitizing substances, reduce excess impurities in pig iron, the choice of Carburant can reduce the cost of casting production.
The use of Carburant
In the smelting process, due to improper ingredients or improper loading and decarbonization and other reasons, sometimes caused by carbon content in steel did not meet the requirements of the top, then to increase the carbon content of molten steel. Commonly used carbonizers are carbonized pig iron, electrode powder, petroleum coke powder, charcoal powder and coke powder. Converter smelting, high-carbon steel, the use of impurities with little oil coke as a Carburant. The requirements for carbonizers for top-blown converter steelmaking are higher in fixed carbon, and ash, volatile and sulfur, phosphorus, nitrogen and other impurities are low and dry, clean and granular.
The fixed carbon component is:
W (C)> 96%, volatiles ≤ 1.0%, w (S) ≤ 0.5%, w (moisture) ≤ 0.55%, particle size 1 - 5mm.
Granularity is too easy to burn easily, too thick to join after floating in the molten steel surface, not easy to be absorbed by molten steel. For the induction furnace particle size of 0.2-6mm, of which steel and other ferrous metal particle size in the 1.4-9.5mm, high carbon steel requires low nitrogen, particle size of 0.5-5mm, and so the specific needs of the furnace according to the specific smelting The type of detail and so the specific judgment and selection.
1. Furnace input method:
Carbonizers are suitable for smelting in the induction furnace, but the specific use is not the same depending on the process requirements.
(1) in the intermediate frequency furnace smelting in the use of Carburant, according to the ratio or carbon equivalent requirements with the material added to the lower part of the furnace, the recovery rate of 95% or more;
(2) If the carbon content is insufficient to adjust the carbon content, first slag in the furnace, plus Carburant, through the molten iron temperature, electromagnetic stirring or artificial stirring to dissolve the carbon absorption, the recovery rate of about 90%, if The use of low-temperature carbon increase process, that is, only part of the furnace melting, molten iron liquid temperature is low, all the Carburant added to the molten iron at one time, while the solid charge into the molten iron can not let it exposed iron Liquid surface. This method of iron liquid by more than 1.0% carbon.
2. Extra carbon outside the furnace:
(1) package within the sprayed graphite powder
The use of graphite powder to do Carburant, blowing into the amount of 40kg / t, is expected to make iron liquid carbon content from 2% to 3%. With the iron content of iron increased gradually, the utilization of carbon decreased, the temperature of carbon before the carbon temperature of 1600 ℃, the average after the increase of 1299 ℃. The use of nitrogen as a carrier, but in industrial production conditions, with compressed air more convenient, and the compressed air in the air to produce CO, the chemical reaction heat can compensate for part of the temperature drop, and the reduction of CO atmosphere Improve the carbon effect.
(2) the use of carbon to increase the iron
Can be 100-300 purpose graphite powder carburant into the bag, or from the trough with the flow into the iron liquid after the full mixing, as far as possible to dissolve the carbon absorption, carbon recovery rate of about 50%.