Low cost, high-wearability hypereutectic high chromium cast iron and its production method

Abstract

This invention provides a hypereutectic high chromium cast iron cast iron and its making method, the main components of the cast iron as follows: Cú‘3.5í½4.5úÑú¼Mnú‘1.0í½3.0úÑú¼Crú‘17í½30úÑú¼Siú‘0.5í½1.5 úÑú¼Cuú‘1.0í½2.0úÑú¼Pú‘íœ0.06úÑú¼Sú‘íœ0.06úÑú¼Niú‘íœ1úÑú¼the rest is iron. The making method is to use twice gestation transformation dealing method to thin the early produced calcium carbide, wherein the grain such as TiN and NbNin in the alloy of the inoculant can increase the uncleus quantum of the early produced calcium carbide. The rare earth, magnesium and kallium congregate on the surface of the early produced calcium carbide to make them thin and spheric. The inoculant can speed the solidification of the alloy to prohibit the early produced calcium carbide from growing to reach the aim of thinning the early produced calcium carbide. Wherein, the sediment pump overcurrent piece made by the hypereutectic high chromium cast iron cast iron has a better casting charater, resistance, and high using longevity.

Description

technical field [0001] The invention relates to a cast iron and a preparation method thereof, in particular to a low-cost, high-wear-resistant hypereutectic high-chromium cast iron and a production method thereof. The hypereutectic high-chromium cast iron is suitable for manufacturing and conveying highly abrasive slurry Slurry pump flow parts, such as impeller, guard plate and sheath, etc. Background technique [0002] High chromium cast iron is a kind of important wear-resistant material that is widely used. Due to the large amount of high hardness M in the structure 7 C 3 It has excellent wear resistance due to the presence of type carbides, and at the same time has improved toughness compared to other white cast irons due to the rod-shaped distribution of eutectic carbides. Therefore, it is widely used in various wear parts in metallurgy, mining, water conservancy, electric power, chemical industry and other fields, as well as various flow part...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: the mold investment is large, and it is not suitable for the production of single-piece and small-batch slurry pump parts; the maximum amount of inoculant that can be added is limited (generally no more than 1%, the maximum is no more than 2%); The particle size of the agent is small, generally no more than 100um, and there are relatively many impurities such as oxides on the surface, but under the conditions of the invention, these impurities remain in the casting, which has an adverse effect on the toughness of the material

The disadvantages are: the amount of inoculant added is high, and impurities such as oxides on the surface generally remain in the casting, which has an adverse effect on the toughness of the material; the pouring temperature is low, and the fluidity of the alloy liquid is not good, so It is suitable for the production of complex parts such as slurry pump flow parts

However, the article did not introduce the composition of the refiner, and because of the low temperature casting (the temperature of the alloy liquid filling is about 10°C lower than its liquidus line), the filling ability of the alloy liquid is poor, and the rejection rate such as cold shut Higher, the yield of castings is low, and the quality is unstable

In addition, due to the addition of about 2 to 3% of expensive molybdenum, the cost of raw materials is about 3.5 times that of KMTBCr26, so the price of this material when used to manufacture slurry pump flow parts is relatively high

[0011] From the above analysis, it can be seen that due to the complex shape of the slurry pump flow parts, in order to ensure that qualified castings are poured, the filling temperature of the alloy liquid should not be too low; only the inoculation and deterioration in the ladle cannot achieve the refinement of hypereutectic high-chromium cast iron. The purpose of inoculating with the flow (adding an inoculant to the alloy solution at the same time as pouring), even if the purpose of refining the hypereutectic high-chromium cast iron can be achieved, the fluidity of the alloy will become very poor; it is necessary to choose a suitable chemical Composition, that is, to take advantage of the good wear resistance of hypereutectic high cast iron, but also to reduce the cost of materials

However, none of the papers or patents retrieved above have provided a low-cost, high-wear-resistant hypereutectic high-chromium cast iron production method suitable for "production of slurry pump flow parts".

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