Method for preparing hypereutectic high chromium white cast iron

Abstract

The invention discloses a method for preparing hypereutectic high chromium white cast iron. According to the method, steel scrap, pig iron, high carbon ferro-chrome, ferromanganese and ferrosilicon are taken as smelting raw materials. The method comprises the following steps of: preparing the following chemical compositions in percentage by weight: 3.0 to 4.5 percent of C, 15 to 35 percent of Cr, 0.5 to 1.5 percent of Mn, 0.5 to 1.5 percent of Si, less than 0.06 percent of P, less than 0.06 percent of S and the balance of Fe; melting the raw materials in an electric furnace, deoxidizing, quickly pouring a casting fluid in the furnace into a casting ladle; when the temperature is reduced to 1,300-1,350DEG C, pouring the casting fluid into a sand mould for forming; heating a cast in the electric furnace to the temperature of between 700 and 1,000DEG C, keeping the temperature, quickly taking out of the furnace, and forging on a forging machine for forging deformation treatment; and tempering the forged piece to obtain the hypereutectic high chromium cast iron.

Description

technical field [0001] The invention relates to a manufacturing technology of high-chromium cast iron, in particular to a preparation method of wear-resistant hypereutectic high-chromium white cast iron. Background technique [0002] High chromium white cast iron is a kind of important wear-resistant material that is widely used. Due to the large amount of high hardness M in its structure 7 C 3 It has excellent wear resistance due to the presence of type carbides, and the morphology of the carbides is distributed in a rod shape, which improves the toughness compared with other white cast irons. The chromium element in high chromium white cast iron can not only effectively improve the corrosion resistance of the material in the slurry, but also the large amount of chromium-containing hard phase M 7 C 3 Type carbide effectively improves the wear resistance of the material and improves the service life of wear parts. Therefore, it is widely used in various wear parts in met...

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Problems solved by technology

In this method, the mold investment is large, which is not suitable for the production of single or small batch castings; the particle size of the inoculant is small, generally not exceeding 100 μm, and there are relatively many impurities such as oxides on the surface, which will pollute the structure of the casting, which is not conducive to Its toughness improves

[0008] The paper "Scouring erosion resistance of metallic materials used in slurry pump service" published by R.J Llewellyn et al. introduced a hypereutectic high-chromium white cast iron (5C-35%) produced by conventional casting with primary carbide refinement. Erosion wear resistance, but the paper does not give a method for refining primary carbide grains

[0009] The main content of the article "High Carbon and High Chromium White Cast Iron Materials and Its Application" published by Zhang Shangang et al. is: under the condition of low temperature pouring, by adding a refiner to the molten iron (the composition of the refiner is not provided) and about 1% of 0.2-0.3mm alloy iron pellets, although the effect of refining the primary carbides in the hypereutectic alloy (4.0-6.0C-30.0-40.0%) is achieved, but due to the low-temperature casting method, the Castings are prone to defects such as cold shuts, resulting in low yield and unstable quality

[0010] The inventor of the present application has added titanium and boron elements to refine the primary carbides in hypereutectic high-chromium white cast iron. Although the refinement effect is obvious, the formability is not easy to control, and defects such as shrinkage cavities and shrinkage porosity are prone to occur in castings.

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