Wear-resistant composite material suitable for ledge of scraper conveyor and preparation process of wear-resistant composite material

Abstract

The invention provides a wear-resistant composite material for a ledge of a scraper conveyor and a preparation process of the wear-resistant composite material. The preparation process comprises the following steps: 1) uniformly stirring ceramic particles and steel-based self-fluxing alloy powder; (2) adding a binder into the mixed powder, and putting the mixture into a honeycomb mold for compression molding; 3) carrying out vacuum drying on the compression molding part to remove moisture; 4) carrying out vacuum sintering on the dried part, and cooling to obtain a honeycomb-shaped composite material preform; and 4) putting the prefabricated body into a scraper conveyor ledge sand mold, casting smelted hard alloy molten steel, and cooling to obtain the honeycomb-structured particle-reinforced metal-based composite wear-resistant material ledge. The wear resistance of the ledge of the scraper conveyor in the mineral exploitation process is improved, the reinforcement proportion of the cast composite material is increased through the prefabricated body preparation mode, meanwhile, the problem of segregation of reinforced particles is solved through the fixing effect of the metal powder on the ceramic particles, and the service life of the ledge of the scraper conveyor is prolonged.

Description

Technical Field

[0001] The invention relates to a method for preparing a honeycomb composite material suitable for a trough side of a scraper conveyor, and belongs to the technical field of metal-based wear-resistant composite materials. Background Art

[0002] In recent years, ceramic particle reinforced metal-based wear-resistant composite materials with spatial configuration have become a hot topic in research. They have the characteristics of high strength ratio, low cost, configurability, and good processability, and have become the development trend of new wear-resistant materials. Due to the high strength and wear resistance of ceramic materials and the good plasticity and toughness of metal matrix materials, compared with traditional wear-resistant materials, particle reinforced metal-based wear-resistant composite materials often have higher wear resistance and equipment reliability in more complex and harsh underground mining conditions. Therefore, particle reinforced metal-based wear-resistant composite materials are an ideal wear-resistant material. And studies have shown that under the same load conditions, particle reinforced metal-based wear-resistant composite materials with spatial configuration have better wear resistance.

[0003] Chinese invention patent CN104439192 discloses a method for preparing a honeycomb ceramic-metal composite vertical mill roller, which comprises mixing ceramic particles, pore-forming agent and binder in proportion and adding them to a mold to prepare a honeycomb porous preform, then heating the preform to activate the pore-forming agent in the honeycomb porous ceramic preform to obtain a honeycomb porous ceramic preform, placing the preform in a mill sand mold after preheating, casting the smelted tough metal liquid, and forming a composite vertical mill roller after complete solidification, and performing overall heat treatment on the composite vertical mill roller to prepare a honeycomb ceramic-metal composite vertical mill roller. This method uses a binder to bond ceramic particles, and then obtains a composite material by casting. There may be a situation where ceramic particles fall off during the casting process and the metal steel liquid cannot penetrate. Patent 111995422 discloses a method for preparing a honeycomb ceramic material, which comprises mixing a binder, a ceramic precursor and water to obtain a dispersion, and subjecting the dispersion to oriented freezing; then subjecting the obtained block material to solvent replacement and in-situ cross-linking with a cross-linking agent and a poor solvent, and drying the obtained block material and sintering it at a high temperature to obtain a honeycomb ceramic material. The existing preparation methods mostly use gravity casting, negative pressure casting and other casting methods. In the casting process, high melting point metal powder is first used to mechanically combine with ceramic reinforcement phase particles, and at the same time, a binder is added to press it into a ceramic prefabricated block with a certain porosity. Then the prefabricated block is placed in a designed runner mold and a metal liquid casting process is performed according to a certain casting process to obtain the final wear-resistant composite material. Generally speaking, the prefabricated block obtained by this method has a low overall strength because the metal powder and the ceramic particles are only connected to each other by a binder. When the casting speed is too fast during the metal liquid filling process, it is easy to cause the prefabricated block to be insufficient in strength and collapse, destroying its spatial configuration. Therefore, the structural integrity of the prefabricated block during the casting process is also an important guarantee for obtaining good wear resistance of the composite material. At present, spatial configuration composite materials need to improve material density, reduce porosity, and at the same time improve the uniformity of composite material particles and reduce particle segregation to improve the reliability of the prefabricated body. Summary of the invention

[0004] In view of the above problems, the present invention connects ceramic particles and iron-based self-fluxing powder through a binder, and uses a hydraulic press to form a preform, which can effectively reduce the porosity of the composite material; in order to improve the strength of the preform, the pressed preform is subjected to high-temperature vacuum sintering to ensure the integrity of the spatial configuration of the preform during the casting process; at the same time, the iron matrix can provide effective support and bearing for the ceramic particles, reduce the possibility of ceramic particles falling off, fix the ceramic particles, and improve product reliability.

[0005] A new type of wear-resistant material suitable for the trough side of a scraper conveyor is characterized by the following specific steps:

[0006] 1) Preparing a green body of a honeycomb composite material: firstly, ceramic particles, iron-based self-fluxing powder, and a binder are uniformly mixed at a ratio of 10:25 to 90:3 to 10, and the mixture is added into a mold to prepare a green body of a honeycomb composite material;

[0007] 2) preparing a honeycomb composite material preform: heating the green body obtained in step 1, and vacuum drying to evaporate the water in the preform to obtain a honeycomb composite material preform;

[0008] 3) Preheating the prepared honeycomb composite material preform at a temperature of 700 to 800°C

[0009] 4) Preparing a honeycomb composite material casting: placing the honeycomb composite material preform in step 1 into a groove side sand mold, pouring the molten steel liquid, closing the sand box, keeping warm for 2 to 8 hours, and obtaining the prepared honeycomb composite material casting after cooling.

[0010] The iron-based self-fluxing powder is one of No. 45 steel powder, No. 60 steel powder, reduced iron powder, medium manganese steel powder, etc. or a mixture thereof in proportion;

[0011] The ceramic particles are one or more of silicon carbide, titanium carbide, tungsten carbide, zirconium corundum, vanadium carbide, aluminum oxide, zirconium oxide, and titanium boride mixed in any proportion;

[0012] The binder is polyvinyl alcohol solution with a concentration of 3% to 5%.

[0013] High hardness alloy steel is 30SiMn, high chromium alloy, high manganese steel, nickel hard cast iron or high chromium cast iron.

[0014] The beneficial effects of the present invention are:

[0015] The preform is prepared by the green body manufacturing method in powder metallurgy, which improves the designability of the material and can greatly improve its adaptability to the product; through the preparation of the preform, the ceramic particle content is increased, the particle aggregation is reduced, and the wear resistance of the composite material is improved.

[0016] Iron-based self-fluxing powder is added during the preform production process, and the preform is pressed and formed by a hydraulic press. This can effectively reduce the porosity of the composite material and improve the density of the material during the heating process.

[0017] The addition of iron-based self-fluxing powder makes it easy to form a transition zone between the molten steel and the preform during the casting process, improves the integrity of the product, and effectively reduces the possibility of gaps between the ceramic particles and the ductile metal caused by casting. The raw materials for material preparation are simple and easy to obtain, the process is simple, and the equipment requirements are low, which can effectively reduce production costs. The composite material is manufactured by casting, and large products can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a physical picture of the honeycomb-structured particle-reinforced iron-based composite material preform prepared in Example 1;

[0019] Figure 2 This is a scanning electron microscope image of the iron matrix powder of the honeycomb-structured particle-reinforced iron-based composite material prepared in Example 1;

[0020] Figure 3 This is a scanning electron microscope image of the honeycomb particle-reinforced iron-based composite material reinforced particles prepared in Example 1;

[0021] Figure 4 This is a practical application diagram of the honeycomb particle-reinforced iron-based composite material prepared in Example 1;

[0022] Figure 5 This is a surface polishing image of the honeycomb particle reinforced iron-based composite material prepared in Example 1;

[0023] Figure 6 This is a three-body wear morphology image of the honeycomb particle-reinforced iron-based composite material prepared in Example 1; DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1: Honeycomb iron matrix composite material

[0025] Preparation of honeycomb preform green body. Firstly, metal powder, binder and ceramic particles are fully mixed in a ratio of 60:5:40 to obtain a mixture of metal powder and ceramic particles.

[0026] The mixture is poured into a designed honeycomb mold, and a tablet press is used to apply graded pressure to the mold. The pressure is maintained for 5 minutes to increase the bonding strength of the honeycomb green body. The ceramic particles are zirconia toughened alumina particles with a particle size of about 2 mm, the metal powder is Fe45 with a particle size of about 50 μm, and the binder concentration is 3% PVA (polyvinyl alcohol) aqueous solution.

[0027] The honeycomb green body is dehydrated and dried in a vacuum drying oven at 65° C. for 6 hours to fully evaporate the moisture in the green body to obtain a honeycomb composite material preform.

[0028] The preform after removing moisture is placed in a vacuum sintering furnace for high-temperature sintering. The sintering temperature starts at 10°C / min from room temperature to 200°C, then keeps warm for 30 minutes, and then continues to heat to 1000°C. Then the heating rate is adjusted to heat at 5°C / min, followed by keeping warm for 30 minutes. After the insulation is completed, it is cooled with the furnace. After the temperature drops to room temperature, a honeycomb configuration preform can be obtained.

[0029] The prepared honeycomb composite material preform is preheated at a temperature of 700°C.

[0030] The honeycomb composite material preform is placed in the groove side sand mold, and the molten 30SiMn steel liquid is poured at the same time. The sand box is closed and kept warm for 4 hours, and then the sand is dropped to obtain the prepared honeycomb composite material casting.

[0031] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0032] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wear-resistant composite material suitable for the trough side of a scraper conveyor and a preparation process, characterized in that: include: The ceramic particles and the steel-based self-fluxing alloy powder are mixed uniformly to obtain a mixture; The components in the mixture are uniformly mixed by mechanical stirring; a liquid binder is added to the dry-mixed material, the binder is uniformly mixed in a ratio of 10:25 to 90:3 to 10, and the mixture is added to a mold and cold-pressed to form a honeycomb composite material embryo; Putting the honeycomb composite material green body into a vacuum drying oven for vacuum drying to evaporate water in the green body to obtain a dry green body; The dried composite material green body is placed in a vacuum sintering furnace for sintering treatment, and the temperature is initially raised to the decomposition temperature of the liquid binder at a rate of 5-10°C / min and kept at that temperature for 10-15 minutes, and then the temperature is adjusted to rise to a maximum temperature of 700-800°C at a rate of 5-7°C / min, kept at that temperature for 1 hour, and then cooled to room temperature with the furnace to obtain a honeycomb composite material preform; The honeycomb composite material preform is placed in a groove side sand mold, the molten steel liquid is cast, the sand box is closed, the temperature is kept for 2 to 8 hours, and then the sand is dropped to obtain a honeycomb composite material casting.

2. The method for preparing a honeycomb composite material according to claim 1, characterized in that: The iron-based self-fluxing powder is one of Fe45 powder, Fe60 powder, reduced iron powder, medium manganese steel powder, etc. or a mixture thereof in proportion.

3. The method for preparing a honeycomb composite material according to claim 1, characterized in that: The ceramic particles are one or more of silicon carbide, titanium carbide, tungsten carbide, zirconium corundum, vanadium carbide, aluminum oxide, zirconium oxide, and titanium boride mixed in any proportion.

4. The method for preparing a honeycomb composite material according to claim 1, characterized in that: The liquid binder is selected as a polyvinyl alcohol aqueous solution with a concentration of 3% to 10%.

5. The method for preparing a honeycomb composite material according to claim 1, characterized in that: The high-hardness alloy steel in step 4 is 30SiMn steel, high-chromium alloy, high-manganese steel, nickel-hard cast iron or high-chromium cast iron.

6. The method for preparing a honeycomb composite material according to claim 1, characterized in that: The pressure applied in the cold pressing forming method is 200-600 MPa, and the pressure is applied in stages.

7. The method for preparing a honeycomb composite material according to claim 1, characterized in that: The decomposition temperature of the liquid binder is 200-300°C.

Images