Electric furnace smelting high-strength medium heat-resistant alloy cast iron and smelting method thereof

Abstract

The invention discloses high-strength medium-heat-resistance alloy cast iron smelted through an electric furnace and a smelting method of the high-strength medium-heat-resistance alloy cast iron in the technical field of cast iron production. The alloy cast iron is prepared from, by mass, 3.2%-3.4% of carbon, 1.9%-2.2% of silicon, 0.01%-0.06% of phosphorus, 0.06%-0.12% of sulfur, 0.6%-0.9% of manganese, 0.2%-0.35% of chromium, 0.6%-0.9% of copper, 0.005%-0.03% of titanium and the balance iron and inevitable impurities. Different from traditional gray cast iron raw materials, pig iron is not added in the scheme of the invention, but a proportioning process of scrap steel, foundry returns and a carburant is used, and meanwhile, a precious molybdenum alloy is replaced by adopting alloy matching of copper and chromium, so that the manufacturing cost is greatly reduced, in addition, a treatment mode of silicon iron pretreatment of a part of the carburant and tapping composite inoculation is adopted, and the production efficiency is greatly improved. By means of the method, more than 90% of A-type graphite is obtained in a metallographic phase of a casting body, the lanthanum-containing inoculant can promote isometric crystal growth and inhibit dendritic crystal growth in the cast iron solidification process, a feeding channel in molten iron is effectively prolonged, the shrinkage porosity tendency of the casting is reduced, and it is guaranteed that leakage does not exist in an installation pressure test.

Description

technical field [0001] The invention relates to the technical field of cast iron production, in particular to an electric furnace melting high-strength medium heat-resistant alloy cast iron and a melting method thereof. Background technique [0002] With the rapid development of household automobiles and modern industry, the demand for automobile basic components has increased rapidly, the demand for automobile consumption in my country has continued to rise, and the number of automobiles has shown a continuous and rapid increase. [0003] As one of the core components of the automobile, the engine block is one of the engine parts with large size, complex shape, large difference in wall thickness, harsh working conditions (under the effect of cyclic thermal shock and thermal fatigue during work), and high mechanical performance requirements. , is a key part that is extremely difficult to produce. Therefore, the cylinder material is required to have good comprehensive proper...

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Problems solved by technology

[0004] Pig iron must be added to the ingredients when preparing high-strength medium heat-resistant alloy cast iron engine block by traditional electric furnace smelting, so the manufacturing cost is relatively high

Moreover, the traditional electric furnace smelting high-strength medium heat-resistant alloy cast iron needs to add heavy alloy molybdenum element to the chemical composition, which increases the manufacturing cost

In addition, during the inoculation treatment of high-strength medium heat-resistant alloy cast iron smelted in traditional electric furnaces, during the solidification process, conventional inoculants cannot promote the growth of equiaxed crystals during the nucleation and growth process, inhibit the growth of dendrites, and cannot prolong the growth of molten iron. The feeding channel is easy to cause the risk of shrinkage porosity in cast iron

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