A Molding Sand for Reducing Casting Cracks and Its Application

Abstract

The invention belongs to the technical field of preparation of heat-resistant steel castings, and relates to molding sand for reducing cracks on a casting and application of the molding sand. The molding sand is prepared from the following raw material components in parts by weight: 100 parts of roughing sand, 2 to 6 parts of resin, 0.2 to 1 part of a curing agent and 0.6 to 0.9 part of an additive, wherein the additive is Fe4O3 and / or MgO. According to the molding sand, Fe4O3 and / or MgO are or is used as the additive, and the use amounts of the additive and the components and the matching relations between the additive and the components are adjusted, so that the molding sand is obtained. The molding sand is used for casting stainless steel 1.4837, so that the resistance to shrinkage of a stainless steel casting 1.4837 is reduced, and microcracking of the casting in solidification and shrinkage processes is avoided. When the molding sand disclosed by the invention is used for producing a stainless steel (1.4837) turbine shell, the content of Nb added in the melting process can be reduced to be 0.6 percent or lower from 1.5 percent of the mass of molten steel in the prior art, so that the produced turbine shell is free of micro cracks.

Description

technical field [0001] The invention belongs to the technical field of preparation of heat-resistant steel castings, and relates to molding sand for reducing casting cracks and an application thereof. Background technique [0002] In the modern machinery industry, casting is inseparable from automobiles, aerospace, agriculture, metallurgy and daily life. Among them, sand casting is mainly used in the casting production of cast steel and cast iron, which has the characteristics of wide adaptability, low cost and mature technology. [0003] Casting is widely used in the field of automobile manufacturing, such as casting the supercharger installed on the exhaust pipe of the automobile engine. At present, the commonly used materials for the casting of the turbine casing of the automobile supercharger are ductile iron and medium silicon molybdenum cast iron. and high nickel alloys. [0004] Each of the above three materials has its advantages and disadvantages: [0005] Ductil...

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Problems solved by technology

[0010] One of the purposes of the present invention is to adopt 1.4837 stainless steel in the prior art to cast micro-cracks on the surface of the castings and prevent the generation of micro-cracks by adding high content (1.5%) of Nb in the prior art to increase the cost. It is to provide a kind of molding sand that reduces casting cracks. Using the molding sand of the present invention to cast 1.4837 stainless steel can effectively prevent the generation of microcracks, and the addition of Nb in the smelting process is less than 0.6% of the molten steel quality, which greatly reduces the cost.

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