Low-alloy heat-resisting cast iron and preparation method thereof

Abstract

The invention relates to low-alloy heat-resisting cast iron, which comprises the ingredients of 2.5 to 3.5 percent of C, 2.5 to 3.5 percent of Si, 0.1 to 1.0 percent of Cr, less than 1.0 percent of Mn, less than 0.3 percent of P, less than 0.1 percent of S, 1.8 to 4.0 percent of Al, 0.05 to 0.1 percent of Sr and the balance of Fe. The preparation method comprises the steps that: scrap steel, chromium iron, pig iron, silicon iron, pure aluminum and aluminum-strontium intermediate alloy are mixed and smelted according to the mass percentage of the chemical ingredients in the target product, wherein the pure aluminum is placed at the bottom of a casting ladle in advance, after an aluminum block is smelted, the aluminum-strontium intermediate alloy is added, 75SiFe nucleating agents are filled along with flows, and the drossing and the casting are carried out after stirring; in the preparation method, the aluminum content is low, the aluminum-strontium intermediate alloy is matched for carrying out spheroidisation on molten iron; and a protecting film is promoted to be formed on the surface of the cast iron at a high temperature. The low-alloy heat-resisting cast iron has the advantages that the process method is simple, the operation is convenient, the production cost is low, the comprehensive mechanical performance is good, the inoxidizability is high, and the low-alloy heat-resisting cast iron adapts to various application processes requiring repeated heating and cooling, such as crucibles, fire grates and the like for nonferrous metal smelting. The low-alloy heat-resistingcast iron is suitable for industrial production.

Description

technical field [0001] The invention relates to a low-alloy heat-resistant cast iron and a preparation method thereof. It belongs to the technical field of heat-resistant metal materials. technical background [0002] Heat-resistant cast iron refers to cast iron that can be used at high temperatures and whose anti-oxidation or anti-growth performance meets the requirements of use. Because cast iron has excellent casting performance and easy processing performance, cheap price and convenient manufacture, it is widely used in the manufacture of crucibles, glass molds, grate bars, heating furnace accessories, such as furnace bottom plates and heat exchangers for non-ferrous metal smelting. Wait. According to the difference of main components, at present, heat-resistant cast iron is mainly divided into silicon-based heat-resistant cast iron, chromium-based heat-resistant cast iron, aluminum-based heat-resistant cast iron and nickel-based heat-resistant cast iron. [0003] The...

AI Technical Summary

Problems solved by technology

The alloying degree of this kind of conventional cast iron material is low, but its heat resistance is not ideal. The crucible for smelting non-ferrous metals cast with this kind of cast iron is often gradually thinned due to high temperature oxidation, and then cracks, resulting in The crucible is scrapped, which may even cause production accidents. Through actual production verification, its service life is only about 15 days

The crucibles used in factories generally have large volume and quality, and it takes time and effort to replace them, and production needs to be suspended, which seriously affects the efficiency of production and increases the cost of production

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