High-strength cast iron short-flow quick self-purification smelting technology

Abstract

The invention discloses a high-strength cast iron short-flow quick self-purification smelting technology and belongs to the technical field of cast iron production. The high-strength cast iron short-flow quick self-purification smelting technology mainly solves the problem that the matrix structure and the mechanical property of the cast iron are deteriorated due to the hereditary defect of blast furnace molten iron in the short-flow process. According to the technology, 60 to 100 percent of blast furnace molten iron serves as a furnace material; 0 to 40 percent of waste steel and 0.3 to 0.8 percent of 65FeMn adjusting components are added; the smelting overheat temperature reaches the critical temperature of self deoxidization of the blast furnace molten iron; self boiling of the molten iron and boiling under medium-frequency electromagnetic stirring are maintained for a certain time by utilizing the self-purification function of the blast furnace molten iron, so that high-purity molten iron is obtained; high-strength cast with tensile strength of 250 to 350 MPa is produced through inoculation.

Description

technical field [0001] The invention relates to the technical field of cast iron production, in particular to a short-flow rapid self-purifying smelting technology for high-strength cast iron. Background technique [0002] The cast iron short-flow process is to directly use the blast furnace molten iron as the charge, add scrap steel, recycled materials, etc. in a certain proportion, and pour the castings after melting in the electric furnace. This process eliminates the remelting link of the conventional process, can make full use of the crystallization latent heat of molten iron in the blast furnace, reduces the consumption of electric energy or coke, and at the same time greatly reduces the emission of dust and flue gas, which has significant economic and social benefits. However, this process has not been widely used, and can only be used to produce castings with simple shapes and low mechanical performance requirements (tensile strength less than 150MPa), and lacks feas...

AI Technical Summary

Problems solved by technology

For a long time, the main reason affecting the application and promotion of the short-process cast iron is: due to the lack of a solidification link in the short-process cast iron process, a large number of non-metallic inclusions and gases generated during the blast furnace metallurgy process are mixed into the molten iron. During the solidification process, Various inclusions form the irregular graphite core, which makes the graphite form viciously expand, forming the so-called hereditary defects

If in this case, using known techniques in the field for inoculation treatment (inoculation treatment is generally required for high-strength cast iron), it will be counterproductive. Not only can high-strength cast iron not be obtained, but the morphology and mechanical properties of graphite will be further deteriorated.

[0003] At present, most of the cast iron short-process technology adopts overheating, heat preservation and inoculation treatment technology, such as the "Blast Furnace-Intermediate Frequency Electric Furnace Dual Short Process Melting Process" published by Sun Jianxing et al. in the 8th issue of Volume 55 of "Casting". The inoculation effect has been studied. Since the genetic influence of blast furnace molten iron has not been fundamentally eliminated, only HT200 (tensile strength below 200MPa) brand cast iron can be produced.

Another example is the inventor's published patent "Short-flow Production Process for Structural Parts" (200910256118.X), the purification of molten iron requires a special purification agent and purification treatment process, the process flow is relatively complicated, and improper operation of the purification agent will bring Secondary pollution

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