Preparation method of medium silicon-molybdenum ductile iron for casting production

Abstract

The invention relates to a preparation method of medium silicon-molybdenum ductile iron for casting production. The preparation method of the medium silicon-molybdenum ductile iron for casting production comprises the following steps of S1, weighing the following components in percentage by weight: 30 percent of steel scrap, 40 percent of pig iron, and 30 percent of recirculated iron; S2, smelting: firstly adding the steel scrap and a carburant into a smelting furnace, and then sequentially adding the pig iron, the recirculated iron and an ally with the silicon content being 8 percent to 1.2 percent; and obtaining a smelting mixture; S3, spheroidizing and inoculating: pouring the smelting mixture into a rare earth magnesium spheroidizing agent at a time, spheroidizing, calculating a silicon-barium inoculant and a silicon-iron mixture added for inoculating according to the content of the silicon in iron scrap, and obtaining a spheroidized and inoculated reactant; and S4, cooling and forming: placing the spheroidized and inoculated reactant into a corresponding mold, cooling and forming. The preparation method of the medium silicon-molybdenum ductile iron for casting production provided by the invention has the beneficial effects that the spheroidizing grade of the product is ensured to be high, free carbide can be eliminated without the need for heat treatment, the product formability is high, the rejection rate is reduced, and the product yield is improved.

Description

technical field [0001] The invention relates to the field of casting, in particular to a method for preparing medium-silicon-molybdenum nodular iron for casting production. Background technique [0002] The element content of silicon-molybdenum ductile iron for casting production must meet the following requirements: C:3.2--3.8%; Mn:<0.4%; P:<0.06%; Si:3.8--4.2%; Mo: 0.7--0.8%. In the existing preparation process of medium-silicon-molybdenum ductile iron that meets the above requirements, there are the following defects: [0003] 1. The spheroidization level of the obtained product is low, and the matrix structure has free carbides, and additional heat treatment is required to eliminate free carbides; [0004] 2. The formed ability of the obtained product is weak, the qualified rate of the product is low, and the waste product is increased; [0005] 3. The operation and control of smelting in the process are more complicated. Contents of the invention [0006] In...

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Problems solved by technology

[0004] 2. The formed ability of the obtained product is weak, the qualified rate of the product is low, and the waste product is increased;

[0005] 3. The operation and control of smelting in the process are more complicated