CN110586850A

CN110586850A - Wear-resistant part casting coating

Info

Publication number: CN110586850A
Application number: CN201910839614.1A
Authority: CN
Inventors: 邢振国; 赵树国; 常连波; 邢万里; 齐自新; 谭建波; 赵松杰
Original assignee: HANDAN HQ COMPOSITE MATERIAL TECHNOLOGY Co Ltd
Current assignee: HANDAN HQ COMPOSITE MATERIAL TECHNOLOGY Co Ltd
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2019-12-20

Abstract

The invention discloses a wear-resistant part casting coating which is used for casting a wear-resistant part. The aggregate of the coating is aluminum corundum powder and quartz powder, wherein the aluminum corundum powder accounts for 20-50% of the weight of the quartz powder. Calculated by the weight of the aggregate, the solvent water accounts for 30-50%, the suspending agent CMC accounts for 1-4%, the sodium bentonite accounts for 2-5%, the organic adhesive white latex accounts for 2-4%, the preservative accounts for no more than 0.01%, the defoaming agent accounts for no more than 0.01%, the tellurium powder accounts for 1-4%, and the rare earth modifier accounts for 1-4%. The hardness, impact toughness and wear resistance of the wear-resistant part are improved by using the coating, and particularly the impact toughness is obviously improved.

Description

Wear-resistant part casting coating

Technical Field

The invention is applied to the field of wear-resistant part casting, and particularly relates to a coating for brushing the surface of a casting model.

Background

With the development of wear-resistant materials, the wear-resistant parts commonly used at present can be classified into high manganese steel, high chromium cast iron and CADI (austempered ductile iron) according to the materials. The high-manganese steel material is selected for the wear-resistant part under the impact working condition, the high-chromium cast iron material is preferably selected for the wear-resistant part under the friction and wear working condition, the CADI is a novel wear-resistant material developed in recent years, the performance of the CADI is between the two materials, the CADI has good impact toughness and good wear resistance, and the performance of the CADI depends on the technological parameters of the isothermal quenching treatment.

In the casting of wear resistant parts of any material, fine as-cast grains are desired, and in particular high manganese steel, the grain size cannot be adjusted by heat treatment. The fine crystal grains are beneficial to improving the toughness and the strength of the casting and improving the comprehensive performance of the casting.

Disclosure of Invention

The technical problem solved by the invention is as follows: provides a wear-resistant part casting coating which can increase the supercooling degree of molten metal, increase nucleation cores and refine as-cast crystal grains.

The technical scheme adopted by the invention is as follows: the aggregate of the wear-resistant part casting coating is aluminum corundum powder and quartz powder, wherein the aluminum corundum powder accounts for 20-50% of the quartz powder by weight; the coating comprises tellurium powder, a rare earth modifier, a solvent, a suspending agent, an adhesive, a preservative, a defoaming agent and the like; the weight of the aggregate is calculated, tellurium powder accounts for 1-4%, rare earth modifier accounts for 1-4%, solvent water accounts for 30-50%, the suspending agent selects CMC and sodium bentonite, CMC accounts for 1-4%, sodium bentonite accounts for 2-5%, adhesive white latex accounts for 2-4%, preservative accounts for no more than 0.01%, and defoamer accounts for no more than 0.01%.

The invention has the beneficial effects that: the hardness, impact toughness and wear resistance of the wear-resistant part are improved by using the coating, and particularly the impact toughness is obviously improved.

Detailed Description

In the casting industry, in order to prevent the sand burning of the casting, the conventional method is to brush or spray a refractory coating on the surface of the cavity model, but the proportion of the coating used by the casting with different casting processes and different materials is emphasized. The coating is mainly designed for casting wear-resistant parts.

The aggregate of the coating adopts aluminum corundum powder and quartz powder, and in terms of refractoriness, the higher the aluminum corundum powder is, the better the aluminum corundum powder is, but the aluminum corundum powder has higher cost. CADI, high chromium cast iron and high manganese steel are all high alloys, and the casting temperature is gradually increased, so the content of the aluminum corundum powder is preferably reduced under the condition that the refractoriness of molten metal is met. The aluminum corundum powder accounts for 20-50% of the quartz powder by weight, the lower limit of the coating for CADI and high-chromium cast iron is taken, and the upper limit of the coating for high-manganese steel is taken.

In a coating configuration, solvents, suspending agents, binders, preservatives, defoamers, and the like, should also typically be included in the coating. The solvent is water or alcohol, and the safety and the economical efficiency of alcohol are different from those of water, so that the coating solvent is water. The suspending agent is prepared by directly mixing CMC (carboxymethyl cellulose) with water to obtain pasty glue solution. The bentonite has the components of calcium base, sodium base and lithium base, the lithium base has high price and is mostly used for alcohol-based paint, the sodium base has better activity than the calcium base, and particularly, the bentonite is matched with CMC to be used, so that the suspension property is better, and the sodium bentonite is selected as the paint. The adhesive is divided into organic adhesive and inorganic adhesive, the inorganic adhesive is silica sol, glass water and the like, the organic adhesive is starch, white latex, resin and the like, and the white latex is selected as the main adhesive in consideration of comprehensive analysis of price and adhesive force. The preservative is added into the coating to prevent the deterioration of the coating at high temperature in summer, and is not required in the proportion of the coating, and the preservative is generally butyl p-hydroxybenzoate. The defoaming agent is usually dimethyl silicone oil, is used only when foams are more, and is not necessary to be compounded. The proportion of the materials of the coating is calculated according to the weight of aggregate, the proportion of water is 30-50%, the proportion of CMC is 1-4%, the proportion of sodium bentonite is 2-5%, the proportion of white latex is 2-4%, the proportion of preservative is not more than 0.01%, and the proportion of defoaming agent is not more than 0.01%.

On the basis of the above-mentioned compounding and proportioning, the tellurium powder and rare earth alterant powder are added. Tellurium is the strongest in all non-metals, has good electrical conductivity and thermal conductivity, and can make the molten metal generate extremely cold action, thereby playing a role in increasing the supercooling degree of the molten metal. As the specific gravity of the tellurium powder is larger, the coating added with the tellurium powder is required to be in the stirring process from the beginning of the addition until the surface of the model is sprayed or brushed. The added amount of tellurium powder in the coating is 1-4% of the weight of the aggregate. The rare earth alterant powder is added to modify the surface layer of the molten metal, so that the nucleation core of the carbide is improved, the shape of the carbide is improved, the impact toughness of the casting is improved, and the as-cast structure is improved. The addition amount of the rare earth alterant powder of the coating is 1 to 4 percent of the weight of the aggregate. Tellurium powder and rare earth modifier powder are mutually promoted, one is added with the core, and the other is added with the supercooling degree, so that the crystal grains of the as-cast structure are reduced.

The coating is suitable for various casting processes such as lost foam casting, resin sand casting, shell mold casting, metallic casting and the like, and can play a role in improving the as-cast grain size and improve the impact toughness and the wear resistance of a wear-resistant part.

The table below shows the experimental comparison results (average values) of the CADI wear-resistant parts cast by the lost foam, wherein one box has multiple types in a lost foam sand box, the production process parameters are the same, and the parameters comprise molten metal components, pouring temperature, heat treatment parameters and the like, and only the coatings are different.

The following table shows the experimental comparison results (average values) of the resin sand cast high manganese steel wear-resistant parts, wherein different coatings are used for one box and two boxes in a sand box, and the production process parameters are the same. Since the high manganese steel is used under impact conditions, the experimental results of the frictional wear cannot show the wear resistance, so that no data is available in the following table.

The following table shows the experimental comparison results (average values) of the shell type cast high-chromium cast iron wear-resistant parts, wherein one box is used for casting a plurality of parts, different coatings are used on two sides, and the production process parameters are the same.

Therefore, after the coating is adopted, the hardness, the impact toughness and the wear resistance of the wear-resistant part are improved, and although the hardness and the wear resistance are not greatly improved, the impact toughness is obviously improved.

Claims

1. The utility model provides a wear-resisting part foundry coating, the aggregate chooses for use aluminium corundum powder and quartz powder, its characterized in that: the aluminum corundum powder accounts for 20-50% of the quartz powder by weight; the coating comprises tellurium powder and a rare earth modifier, wherein the tellurium powder accounts for 1-4% of the weight of the aggregate, and the rare earth modifier accounts for 1-4% of the weight of the aggregate.

2. The wear part casting coating of claim 1, wherein: also comprises a solvent, a suspending agent, a bonding agent, a preservative and a defoaming agent; the weight of aggregate is calculated, the solvent water accounts for 30-50%, the suspending agent adopts CMC and sodium bentonite, the CMC accounts for 1-4%, the sodium bentonite accounts for 2-5%, the adhesive white latex accounts for 2-4%, the preservative accounts for no more than 0.01%, and the defoaming agent accounts for no more than 0.01%.