High-intensity gray pig iron inoculator and preparation method thereof

Abstract

The invention discloses a high-intensity gray pig iron inoculator and a preparation method thereof and belongs to the technical field of casting. The high-intensity gray pig iron inoculator comprises the following chemical components in percentage by weight: 65 to 72 percent of Si, 0.5 to 1.2 percent of Al, 0.5 to 1.5 percent of Zr, 0.6 to 1.8 percent of RE, 4.0 to 6.0 percent of Mn, 0.4 to 1.2 percent of Sn (or 0.1 to 0.4 percent of Sb), less than 0.2 of C, less than 0.02 of S, less than 0.05 of P, and the balance of iron and unavoidable impurities. The inoculator can obviously reduce chilling tendency, refine graphite and reduce wall thickness and sensitivity of tissues and obviously increase pearlite content, so that tensile strength of gray pig iron is improved. For base iron with the same components, compared with a common 75 silicon iron inoculator, the high-intensity gray pig iron inoculator has the advantage that the tensile strength of cast iron applying the high-intensity gray pig iron inoculator can be improved by 30 to 60MPa.

Description

technical field [0001] The invention relates to an inoculant for high-strength gray cast iron and a preparation method thereof, belonging to the technical field of casting. Background technique [0002] The inoculant is a processing aid that can promote graphitization, reduce whitening tendency, improve graphite morphology and distribution, increase the number of eutectic groups, and refine the matrix structure. It has a good effect in a short time (about 5-8 minutes) after inoculation treatment, and is one of the most effective or economical ways to improve the performance of castings. [0003] With the development of the machinery industry, the strength requirements for gray cast iron are getting higher and higher. The existing SiFe75 alloy and other inoculants cannot improve the strength of gray cast iron, so they cannot meet the strength requirements of castings. In order to improve the strength of gray cast iron, it is necessary to increase the amount of steel scrap ad...

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Problems solved by technology

[0003] With the development of the machinery industry, the strength requirements for gray cast iron are getting higher and higher. The existing SiFe75 alloy and other inoculants cannot improve the strength of gray cast iron, so they cannot meet the strength requirements of castings.

In order to improve the strength of gray cast iron, it is necessary to increase the amount of steel scrap added in the furnace to reduce the carbon equivalent of cast iron. The production results show that the mechanical strength of cast iron meets the requirements, but at the same time the following problems appear: (1) due to the scrap steel in the furnace charge The addition amount increases, the scrap steel quality is not high, the surface corrosion is serious, the gas content in the cast iron increases, the percentage of castings scrapped due to pores increases, and a lot of raw materials are wasted; (2) The internal quality of castings is uneven, and the width and thickness of castings are different. The hardness disparity is large; (3) the eutectic group is thick, and the processing performance is not good

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