A kind of high-strength and high-toughness cast steel lost foam coating and preparation method thereof

Abstract

The invention relates to the technical field of foundry coatings, in particular to a high-strength and high-toughness lost foam coating for cast steel and a preparation method thereof. The proportions of components by weight are: 100 parts of refractory aggregates, 2 to 4 parts of sintering aids, and 2 parts of suspending agents. ~4 parts, 3-5 parts of binder, 0.5-1.5 parts of thickener, 0.5-0.8 part of defoamer, 0.1-0.5 part of polypropylene fiber, 0.5-3 parts of inorganic whisker, 0.1-0.7 part of dispersant part, wherein, the inorganic whiskers are one or more of silicon carbide whiskers or quartz fibers, the sintering aid is one or more of alumina micropowder or fumed silica, and the present invention utilizes polypropylene fibers and The inorganic whiskers compound the coating, so that the lost foam coating has high high, medium and low temperature strength, high air permeability, good wax mold wettability and adhesion, and the coating is easy to peel off when falling sand, which can be batched. It is used in small and medium-sized steel castings, and at the same time, it can be used in lost foam castings with complex shapes by taking advantage of its high strength and high toughness.

Description

technical field [0001] The invention relates to the technical field of foundry coatings, in particular to a high-strength and high-toughness lost foam coating for cast steel and a preparation method thereof. Background technique [0002] Lost foam casting is to bond and combine paraffin or foam models (hereinafter collectively referred to as wax models) similar to the size and shape of castings into model clusters. After brushing refractory paint and drying, they are buried in molding sand for vibration modeling. Pouring can be carried out without mold release. When pouring, because the wax mold can be completely vaporized and burnt out into gas under the action of high-temperature metal liquid, the liquid metal can replace the position of the wax mold and form a casting after cooling and solidification. The coatings used in them are called lost foam coatings. [0003] There are high requirements for the coating, which requires high air permeability, high refractoriness, a...

AI Technical Summary

Problems solved by technology

Among them, the lost foam coating for ordinary cast steel has poor adhesion to wax patterns, low strength, poor fire resistance, and large gas generation, which is likely to cause defects such as sand sticking, sand holes, pores, and carbon slag in castings. Most of them need to be coated many times. When the coating reaches a certain thickness, its high-temperature strength can be guaranteed, but when the coating is too thick, the gas permeability of the coating will become poor. After pouring molten iron into the molding sand, the wax mold will be burned or vaporized at high temperature, and the gas volume will increase instantaneously. Large, if the coating has insufficient air permeability, the gas will break through the coating, causing the coating to crack, which will easily cause defects such as sand staining and coating skin in the casting.

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