Heat-resisting steel and preparation method thereof

Abstract

The invention provides heat-resisting steel and a preparation method thereof. The method comprises the steps of mixing a first part by mass of Fe with C, Si, Mn, Cr, Ni, Mo, S and P, and smelting so as to obtain liquid steel; and covering a second part by mass of Fe on the surface of rare earth, pouring the liquid steel, and standing, thereby obtaining the heat-resisting steel, wherein the particle diameter of the rare earth is nano-scale and / or micron-scale. Compared with the prior art, the method has the advantages that the rare earth with the nano-scale or micron-scale particle diameter is adopted to modify the heat-resisting steel, the surface activation energy of the nano-scale and / or micron-scale rare earth is higher, the surface of the rare earth is covered by iron powder, and then, the liquid steel is added, so that the rare earth can be isolated from the air, the time of contact between the rare earth and the liquid steel is shortened, the oxidation burning loss is reduced, then, the modification effect of a rare-earth element on the heat-resisting steel is improved, basic crystal grains of the microstructure of the heat-resisting steel are refined and have the effect of refined crystal grains, meanwhile, the high-temperature elongation percentage of the heat-resisting steel can be increased, and the oxidation resistance of the heat-resisting steel is improved.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, and in particular relates to a heat-resistant steel and a preparation method thereof. Background technique [0002] Heat-resistant steel refers to steel with oxidation resistance, sufficient high-temperature strength and good heat resistance under high temperature conditions. Heat-resistant steel includes two types: anti-oxidation steel and heat-strength steel: anti-oxidation steel, also referred to as non-skinned steel, generally requires better chemical stability, but bears a lower load; Steel with high oxidation resistance and high high temperature strength, which has high strength and good chemical stability at high temperature. Heat-resistant steel is often used in the manufacture of boilers, steam turbines, power machinery, industrial furnaces, and parts that work at high temperatures in industrial sectors such as aviation and petrochemicals. In addition to high temperature strength a...

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Problems solved by technology

[0005] In the production or preparation process of rare earth heat-resistant steel, the addition amount of rare earth elements is different, and its absorption effect is different during the solidification process of molten steel, so the modification effect on steel is quite different: if the addition amount is too small, the modification effect is small; If the amount added is too much, it is easy to have defects such as inclusions in the steel structure, which will obviously damage the mechanical properties and high temperature corrosion resistance of the heat-resistant steel.

[0006] Moreover, when the cast alloy is smelted, whether it is an inoculant or a modifier, when it is added to the alloy liquid, its particle size should be kept at a certain size, generally at least millimeter level, if the size is too small, for rare earth elements, it will be melted, If the size is too large, it is not conducive to the role of rare earth elements. Therefore, the utilization rate of rare earth elements in heat-resistant steel needs to be improved.

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