Application of carburizing agent in synthetic cast iron production

　　There are many coarse hypereutectic graphite in pig iron. This kind of coarse graphite is hereditary. The melting temperature is low, and the coarse graphite is not easy to be eliminated. The coarse graphite is inherited from the liquid to the solid cast iron structure. On the one hand, it reduces the mechanical properties that the cast iron can achieve. On the other hand, the existence of the coarse graphite weakens the expansion effect of graphitization precipitation that should have occurred in the solidification process, The shrinkage tendency of molten iron during solidification will be increased. In addition, the coarse graphite will easily fall off during subsequent processing, forming surface pits and affecting the surface finish of the casting.

　　And there are many impurity elements in pig iron. For example, a small amount of ti.p.v, B, etc. will have a negative impact on the casting and deteriorate the matrix structure and graphite morphology. Therefore, during electric furnace smelting, the amount of pig iron charge shall be reduced as much as possible, and graphite carburizing agent shall be used to ensure high carbon equivalent and relatively increase the amount of scrap steel.

　　Thus, under the condition of high-temperature melting, the cast iron after carburizing treatment with carburizing agent generates a large number of dispersed heterogeneous crystal cores in the molten iron, reduces the undercooling degree of the molten iron, and promotes the formation of graphite structure dominated by A-type graphite; At the same time, due to the small amount of pig iron, its genetic effect is greatly weakened, so the branch of A-type graphite sheet is not easy to grow, which is conducive to improving mechanical properties, reducing shrinkage tendency and improving processing performance. High quality molten iron can be obtained by carburizing. Compared with the high scrap content of the same composition, its mechanical properties are also half a grade lower.

　　Therefore, compared with the traditional large proportion of pig iron, the new process of adding carburizing agent is superior in terms of cost and finished product performance.

Comments

Post a Comment

Popular posts from this blog

Study on impurities in high purity flake graphite

Image
 　　For the analysis of trace impurities in high-purity flake graphite, the sample is usually pre ashed or wet digested to remove carbon, the ash is dissolved with acid, and then the impurity content in the solution is determined. The ashing method does not need to use ultra pure acid to dissolve the ash, thus avoiding the risk of introducing the elements to be measured, so it is used more. It is also very difficult to detect the ash content of high-purity flake graphite, because the enriched ash needs to be burned at high temperature, and it is difficult to separate the ash from the sample boat at high temperature, which makes it impossible to accurately determine the composition and content of impurities. 　　The existing methods all take advantage of the characteristic that the platinum crucible does not react with acid, use the platinum crucible to burn the high-purity flake graphite to enrich ash, and then directly heat the sample in the crucible with acid to dissolve th
Read more

General technical index requirements for electrode paste

Image
 Electrode occupies an important position in submerged arc furnace. The working conditions of the electrode are bad, the current passing through is high, the temperature difference between the two ends is large, and the production is affected by the impact of mechanical, electrical and charge collapse... Mechanical strength, higher electrical resistivity, better thermal shock resistance, oxidation resistance and smaller thermal expansion coefficient. Generally speaking, the quality of electrode paste is controlled by the following five indicators: 1. Ash: Ash is the residue of electrode paste when it is burnt to constant weight at 850℃-870℃. It belongs to inorganic minerals. It has high ash resistivity, poor strength, high power consumption, and large electrode consumption. In the event of a hard breaking accident, the ash content is a very important indicator, and the lower the better. 2. Volatile matter: Volatile matter refers to the mass loss of electrode paste under the condition o
Read more

Performance characteristics of anthracite electrode paste

 Anthracite is the main raw material of electrode paste. The performance of anthracite is related to the performance of electrode paste. Therefore, it is necessary to understand and discuss the performance of anthracite to ensure the quality of electrode paste. Anthracite coal in China is mainly distributed in Shanxi, Ningxia and Guizhou. Shanxi is the origin of anthracite, which is mainly produced in Yangquan and Jincheng. Anthracite is an indispensable raw material for carbon industry. It is mainly used in semi graphite cathode carbon block, electric furnace carbon block, blast furnace carbon block, carbon electrode and various pastes. Studying and discussing various properties of anthracite is very beneficial to improve the quality of carbon products.
Read more