Special coating for bimetallic composite casting and preparation method thereof

Abstract

The present invention discloses a method for preparing a special bimetallic composite casting coating, which comprises 96-98 wt% of refractory powder, 1.0-3.0 wt% of a binder, 0.01-0.1 wt% of a surfactant, and 0.2-0.5 wt% of a suspending agent, wherein the sum of the mass percentages of the above components is 100 wt%. The present invention simultaneously satisfies the requirements of good suspension, coating, uniformity, refractoriness, and high temperature resistance. The present invention also discloses a special bimetallic composite casting coating, which is used to prepare the special bimetallic composite casting coating of the present invention, comprising taking materials, adding water to the refractory powder, and then adding a high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stirring to complete the preparation. The present invention solves the problem of requiring a refractory coating with good suspension, coating, uniformity, refractoriness, and high temperature resistance in the hammerhead composite preparation process.

Description

Technical Field

[0001] The invention belongs to the technical field of casting coatings, relates to a special coating for bimetallic composite casting, and also relates to a preparation method of the special coating for bimetallic composite casting. Background Art

[0002] Faced with fierce competition in the international high-tech sector, the transformation and upgrading of the manufacturing industry is imperative, and the new materials industry is the foundation of this transformation and upgrading. Specifically, materials with a single structure and performance are no longer able to meet the needs of equipment updates and upgrades. Bimetallic composite casting is a new composite material preparation method that has gradually matured and developed in recent years. Its principle is to fuse two metals that meet different performance requirements into one through metallurgical composite technology, thereby achieving the purpose of improving performance and extending service life. The hammer head is the main consumable component of coal crushing equipment. During use, the hammer handle is constantly subjected to alternating bending stress and impact force, while the hammer head is primarily subjected to strong impact force and friction. The bimetallic casting and forging composite preparation process can fundamentally ensure the hammer head's impact resistance and improve its wear resistance, thereby extending the service life of equipment components, reducing component replacement and maintenance costs, and improving equipment productivity.

[0003] This composite hammerhead production process utilizes a specialized casting process called lost foam casting (LVC). A prefabricated hammer handle is precisely fixed within a hammerhead mold made of polystyrene foam, and then a refractory coating is applied to the entire surface. This coating must exhibit excellent adhesion to both the polystyrene foam and the forged steel hammer handle, preventing scaling and cracking during subsequent coating drying and metal pouring. It must also possess sufficient strength to resist cracking and breakage during mold handling and sand filling, and possess excellent refractoriness to prevent chemical bonding with the metal during casting. Therefore, a specialized coating was required to meet these requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a special coating for bimetallic composite casting, which satisfies the requirements of good suspension, coating, uniformity, refractoriness and high temperature resistance.

[0005] Another object of the present invention is to provide a method for preparing a special coating for bimetallic composite casting, which solves the problem of requiring a refractory coating with good suspension, coating, uniformity, refractoriness and high temperature resistance in the hammer head composite preparation process.

[0006] The first technical solution adopted by the present invention is a bimetallic composite casting special coating composed of 96.4wt% to 98.0wt% of refractory powder, 1.0wt% to 3.0wt% of binder, 0.01wt% to 0.1wt% of surfactant and 0.2wt% to 0.5wt% of suspending agent, wherein the sum of the mass percentages of the above components is 100wt%;

[0007] The suspending agent adopts a high molecular compound sodium carboxymethyl cellulose emulsion, and the molecular formula of the high molecular compound sodium carboxymethyl cellulose is [C6H7O2(OH)2CH2COONa]n.

[0008] The first technical solution of the present invention is also characterized in that:

[0009] The refractory powder comprises 3 to 5 parts of corundum, 2 to 3 parts of quartz sand and 1 to 3 parts of zircon sand in parts by mass.

[0010] The binder is sodium bentonite.

[0011] The surfactant is a fluorinated surfactant.

[0012] The second technical solution adopted by the present invention is a method for preparing a bimetallic composite casting special coating, which is used to prepare the bimetallic composite casting special coating of the present invention, specifically according to the following steps:

[0013] Step 1, weighing 96.4wt% to 98.0wt% of refractory powder, 1.0wt% to 3.0wt% of binder, 0.01wt% to 0.1wt% of surfactant and 0.2wt% to 0.5wt% of high molecular weight sodium carboxymethyl cellulose emulsion according to mass percentage, the sum of the mass percentages of the above components being 100wt%;

[0014] Step 2: adding water to the refractory powder, and then adding a high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stirring to complete the preparation.

[0015] The second technical solution of the present invention is also characterized in that:

[0016] The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is as follows:

[0017] At room temperature, evenly add the polymer compound sodium carboxymethyl cellulose into water and stir. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water, stop stirring and allow the polymer compound sodium carboxymethyl cellulose and water to penetrate and fuse with each other in a static state, so that the mixed paste is in a uniform state with a smooth surface.

[0018] The content of the high molecular compound sodium carboxymethyl cellulose in the mixed glue is 1wt% to 2wt%.

[0019] The standing time of the high molecular compound sodium carboxymethyl cellulose and water is 10 hours to 20 hours.

[0020] In step 2, the stirring time is 20 min to 30 min, and the stirring speed is 800 r / min to 1000 r / min.

[0021] The refractory powder comprises 3 to 5 parts of corundum, 2 to 3 parts of quartz sand and 1 to 3 parts of zircon sand according to the mass ratio;

[0022] The binder is sodium bentonite;

[0023] The surfactant is a fluorinated surfactant.

[0024] The beneficial effects of the present invention are:

[0025] The present invention's method for preparing a bimetallic composite casting coating utilizes a combination of long-chain sodium carboxymethylcellulose and sodium bentonite to maintain the coating powder in an aqueous solution for extended periods of time, fully utilizing the functions of each coating component during use. A highly stable fluorosurfactant is used to enhance the coating's adhesion to the polystyrene foam mold and metal components, resulting in excellent coating properties and adhesion. This effectively enhances the coating's strength, preventing cracking and flaking at both room and high temperatures. A combination of corundum, zircon, and quartz powders serves as the refractory powder for the casting coating, offering high refractoriness, excellent air permeability, and superior adhesion. The water-based coating is simple to prepare, economical, and environmentally friendly.

[0026] The special coating for bimetallic composite casting of the present invention has good suspension property, good coating property, uniform coating thickness, good high-temperature crack resistance and special application value. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to specific embodiments.

[0028] Example 1

[0029] This embodiment provides a special coating for bimetallic composite casting, which is composed of 96.4wt% of refractory powder, 3.0wt% of sodium bentonite, 0.1wt% of fluorosurfactant and 0.5wt% of suspending agent.

[0030] The suspending agent adopts a high molecular compound sodium carboxymethyl cellulose emulsion, and the molecular formula of the high molecular compound sodium carboxymethyl cellulose is [C6H7O2(OH)2CH2COONa]n.

[0031] The refractory powder includes corundum, quartz sand and zircon sand, and the mixing mass ratio of the corundum, quartz sand and zircon sand is 5:3:1.

[0032] This embodiment also provides a method for preparing a bimetallic composite casting coating, which is used to prepare the bimetallic composite casting coating of the present invention, and is specifically implemented according to the following steps:

[0033] Step 1, weighing 96.4wt% of refractory powder, 3.0wt% of sodium bentonite, 0.1wt% of fluorosurfactant and 0.5wt% of high molecular compound sodium carboxymethyl cellulose emulsion according to mass percentage;

[0034] Step 2: add water to the refractory powder, and then add the high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stir. The stirring time is 20 minutes and the stirring speed is 800 r / min to complete the preparation.

[0035] The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is as follows:

[0036] At room temperature (20° C.), the polymer compound sodium carboxymethyl cellulose is evenly added to water and stirred. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water and no obvious large lumps are present, stirring is stopped. The polymer compound sodium carboxymethyl cellulose and water are allowed to mutually penetrate and fuse while standing. The polymer compound sodium carboxymethyl cellulose and water are allowed to stand for 10 hours until the mixed paste is uniform, has a smooth surface, and is nearly colorless and transparent. The content of the polymer compound sodium carboxymethyl cellulose in the mixed paste is 1 wt %.

[0037] The method of using the special bimetallic composite casting coating of this embodiment is: dip-coating the material on the polystyrene foam mold and the metal hammer handle by the dip coating method, controlling the coating thickness to 1.0 mm, and drying at 55° C. for 48 hours.

[0038] Example 2

[0039] This embodiment provides a special coating for bimetallic composite casting, which is composed of 96.9wt% of refractory powder, 1.0wt% of sodium bentonite, 0.01wt% of fluorosurfactant and 0.2wt% of suspending agent.

[0040] The suspending agent adopts a high molecular compound sodium carboxymethyl cellulose emulsion, and the molecular formula of the high molecular compound sodium carboxymethyl cellulose is [C6H7O2(OH)2CH2COONa]n.

[0041] The refractory powder comprises corundum, quartz sand and zircon sand, and the mixing mass ratio of the corundum, quartz sand and zircon sand is 4:3:2.

[0042] This embodiment also provides a method for preparing a bimetallic composite casting coating, which is used to prepare the bimetallic composite casting coating of the present invention, and is specifically implemented according to the following steps:

[0043] Step 1, weighing 96.9wt% of refractory powder, 1.0wt% of sodium bentonite, 0.01wt% of fluorosurfactant and 0.2wt% of high molecular compound sodium carboxymethyl cellulose emulsion according to mass percentage;

[0044] Step 2: add water to the refractory powder, and then add the high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stir. The stirring time is 30 minutes and the stirring speed is 1000 r / min to complete the preparation.

[0045] The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is as follows:

[0046] At room temperature, the polymer compound sodium carboxymethyl cellulose is evenly added to water and stirred. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water, stirring is stopped, and the polymer compound sodium carboxymethyl cellulose and water are allowed to mutually penetrate and fuse in a static state. The polymer compound sodium carboxymethyl cellulose and water are allowed to stand for 20 hours until the mixed paste is in a uniform state with a smooth surface. The content of the polymer compound sodium carboxymethyl cellulose in the mixed paste is 2 wt%.

[0047] The method of using the special bimetallic composite casting coating of this embodiment is: dip-coating the material on the polystyrene foam mold and the metal hammer handle by the dip coating method, controlling the coating thickness to 3.0 mm, and drying at 70° C. for 72 hours.

[0048] Example 3

[0049] This embodiment provides a special coating for bimetallic composite casting, which is composed of 98wt% refractory powder, 1.5wt% sodium bentonite, 0.05wt% fluorosurfactant and 0.45wt% suspending agent.

[0050] The suspending agent adopts a high molecular compound sodium carboxymethyl cellulose emulsion, and the molecular formula of the high molecular compound sodium carboxymethyl cellulose is [C6H7O2(OH)2CH2COONa]n.

[0051] The refractory powder comprises corundum, quartz sand and zircon sand, and the mixing mass ratio of the corundum, quartz sand and zircon sand is 4:3:3.

[0052] This embodiment also provides a method for preparing a bimetallic composite casting coating, which is used to prepare the bimetallic composite casting coating of the present invention, and is specifically implemented according to the following steps:

[0053] Step 1, weighing 98wt% of refractory powder, 1.5wt% of sodium bentonite, 0.05wt% of fluorosurfactant and 0.45wt% of high molecular compound sodium carboxymethyl cellulose emulsion according to mass percentage;

[0054] Step 2: add water to the refractory powder, and then add the high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stir. The stirring time is 25 minutes and the stirring speed is 900 r / min to complete the preparation.

[0055] The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is as follows:

[0056] At room temperature, the polymer compound sodium carboxymethyl cellulose is evenly added to water and stirred. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water, the stirring is stopped, and the polymer compound sodium carboxymethyl cellulose and water are allowed to mutually penetrate and fuse in a static state. The polymer compound sodium carboxymethyl cellulose and water are allowed to stand for 15 hours until the mixed paste is in a uniform state with a smooth surface. The content of the polymer compound sodium carboxymethyl cellulose in the mixed paste is 1.5 wt%.

[0057] The method of using the special coating for bimetallic composite casting in this embodiment is: dip-coating the material on the polystyrene foam mold and the metal hammer handle by the dip coating method, controlling the coating thickness to 2.0 mm, and drying at 60° C. for 65 hours.

[0058] Example 4

[0059] This embodiment provides a special coating for bimetallic composite casting, which is composed of 97.66wt% of refractory powder, 2wt% of sodium bentonite, 0.04wt% of fluorosurfactant and 0.3wt% of suspending agent.

[0060] The suspending agent adopts a high molecular compound sodium carboxymethyl cellulose emulsion, and the molecular formula of the high molecular compound sodium carboxymethyl cellulose is [C6H7O2(OH)2CH2COONa]n.

[0061] The refractory powder comprises corundum, quartz sand and zircon sand, and the mixed mass ratio of the corundum, quartz sand and zircon sand is 3:3:3.

[0062] This embodiment also provides a method for preparing a bimetallic composite casting coating, which is used to prepare the bimetallic composite casting coating of the present invention, and is specifically implemented according to the following steps:

[0063] Step 1, weighing 97.66wt% of refractory powder, 2wt% of sodium bentonite, 0.04wt% of fluorosurfactant and 0.3wt% of high molecular compound sodium carboxymethyl cellulose emulsion according to mass percentage;

[0064] Step 2: add water to the refractory powder, and then add the high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stir. The stirring time is 23 minutes and the stirring speed is 850 r / min to complete the preparation.

[0065] The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is as follows:

[0066] At room temperature, the polymer compound sodium carboxymethyl cellulose is evenly added to water and stirred. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water, the stirring is stopped, and the polymer compound sodium carboxymethyl cellulose and water are allowed to mutually penetrate and fuse in a static state. The polymer compound sodium carboxymethyl cellulose and water are allowed to stand for 12 hours until the mixed paste is in a uniform state with a smooth surface. The content of the polymer compound sodium carboxymethyl cellulose in the mixed paste is 1.3 wt%.

[0067] The method of using the special coating for bimetallic composite casting in this embodiment is: dip-coating the material on the polystyrene foam mold and the metal hammer handle by the dip coating method, controlling the coating thickness to 2.2 mm, and drying at 70° C. for 50 hours.

[0068] Example 5

[0069] This embodiment provides a special coating for bimetallic composite casting, which is composed of 97.52wt% of refractory powder, 2.0wt% of sodium bentonite, 0.08wt% of fluorosurfactant and 0.4wt% of suspending agent.

[0070] The suspending agent adopts a high molecular compound sodium carboxymethyl cellulose emulsion, and the molecular formula of the high molecular compound sodium carboxymethyl cellulose is [C6H7O2(OH)2CH2COONa]n.

[0071] The refractory powder comprises corundum, quartz sand and zircon sand, and the mixing mass ratio of the corundum, quartz sand and zircon sand is 3:2:2.

[0072] This embodiment also provides a method for preparing a bimetallic composite casting coating, which is used to prepare the bimetallic composite casting coating of the present invention, and is specifically implemented according to the following steps:

[0073] Step 1, weighing 97.52wt% of refractory powder, 2.0wt% of sodium bentonite, 0.08wt% of fluorosurfactant and 0.4wt% of high molecular compound sodium carboxymethyl cellulose emulsion according to mass percentage;

[0074] Step 2: add water to the refractory powder, and then add the high molecular compound sodium carboxymethyl cellulose emulsion to the refractory powder after adding water and stir. The stirring time is 28 minutes and the stirring speed is 860 r / min to complete the preparation.

[0075] The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is as follows:

[0076] At room temperature, the polymer compound sodium carboxymethyl cellulose is evenly added to water and stirred. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water, stirring is stopped, and the polymer compound sodium carboxymethyl cellulose and water are allowed to mutually penetrate and fuse in a static state. The polymer compound sodium carboxymethyl cellulose and water are allowed to stand for 16 hours until the mixed paste is in a uniform state with a smooth surface. The content of the polymer compound sodium carboxymethyl cellulose in the mixed paste is 1 wt%.

[0077] The method of using the special bimetallic composite casting coating of this embodiment is: dip-coating the material on the polystyrene foam mold and the metal hammer handle by the dip coating method, controlling the coating thickness to 1.8 mm, and drying at 58° C. for 66 hours.

[0078] The above embodiment is compared with the following comparative example to verify the performance of the special coating for bimetallic composite casting of the present invention.

[0079] Comparative Example 1

[0080] This comparative example provides a cast steel lost foam casting coating and a preparation method thereof. Compared with Example 1, the refractory components of the bimetallic composite casting special coating are different, the suspending agent is bentonite, and no special surfactant is added. The rest is the same as Example 1.

[0081] Comparative Example 2

[0082] This comparative example provides a coating for lost foam casting of large steel castings and a preparation method thereof. Compared with Example 1, the components of the coating are different, wherein the suspending agent is sodium carboxymethyl cellulose gel, and the rest are the same as Example 1.

[0083] Comparative Example 3

[0084] This comparative example provides a commercially available powder coating for lost foam casting of steel castings.

[0085] The coatings of Examples 1 to 5 and Comparative Examples 1 to 3 were sprayed on polystyrene foam films and dried at 60 to 70° C. for 72 h. The coating thickness was measured and the performance was tested. The results are shown in Table 1.

[0086] Table 1 Coating performance test comparison table

[0087]

[0088]

[0089] As shown in Table 1, the comprehensive performance of the special coatings prepared in Examples 1 to 5 is much better than that in Comparative Examples 1 to 3. The density of the special coatings in Examples 1 to 5 is 1.49 g / cm 3 ~1.56g / cm 3, viscosity 11.8s ~ 12.5s, coating thickness 1.5mm ~ 3.0mm, uniform thickness, with good coating properties; 24h suspension is 98% ~ 99%, with good suspension properties; after drying at room temperature, there is no cracking or blistering, indicating that the coating has high strength, high temperature resistance and good crack resistance. After high-temperature baking, there is no cracking in the coating shell.

[0090] Compared with Comparative Example 1 (suspending agent is bentonite), Comparative Example 2 (suspending agent is sodium carboxymethyl cellulose), and Comparative Example 3 (ordinary commercially available cast steel coating), the suspending agent used in Example 1 is high-molecular sodium carboxymethyl cellulose, which is used in combination with bentonite to further improve the dispersibility of the powder, and the 24-hour suspension of the coating is maintained at 98% to 99%, fully exerting the function of the aggregate of the composite coating; the use of a fluorine surfactant with good stability makes the bonding force between the coating and the polystyrene foam mold and the metal part stronger, so that the coating has good coating and adhesion, effectively improves the strength of the coating, and prevents the coating from cracking or peeling at room temperature and high temperature.

Claims

1. Bimetallic composite casting special coating, characterized by: The invention is composed of 96.4wt% to 98.0wt% of refractory powder, 1.0wt% to 3.0wt% of binder, 0.01wt% to 0.1wt% of surfactant and 0.2wt% to 0.5wt% of suspending agent, wherein the sum of the mass percentages of the above components is 100wt%; The suspending agent is a high molecular compound sodium carboxymethyl cellulose emulsion, the molecular formula of which is [C6H9O4·O·CH2COONa]n; The refractory powder comprises 3-5 parts of corundum, 2-3 parts of quartz sand and 1-3 parts of zircon sand in parts by mass; The binder is sodium bentonite; The surfactant is a fluorosurfactant; The preparation process of the polymer compound sodium carboxymethyl cellulose emulsion is specifically as follows: At room temperature, evenly add the polymer compound sodium carboxymethyl cellulose into water and stir. When the polymer compound sodium carboxymethyl cellulose is evenly dispersed in the water, stop stirring and allow the polymer compound sodium carboxymethyl cellulose and water to penetrate and fuse with each other in a static state. The static time is 10h~20h, so that the mixed paste is in a uniform state with a smooth surface. The content of the high molecular compound sodium carboxymethyl cellulose in the mixed glue is 1 wt% to 2 wt%.

Images