Excavator bucket tooth and forming process

Abstract

The invention relates to the technical field of excavator bucket tooth preparation, and discloses an excavator bucket tooth and a forming process, a precoated sand process is adopted for preparing a large excavator bucket tooth, the production efficiency is remarkably improved, and the production cost is reduced; the precoated sand process does not need complex die preparation and high-temperature forging processes, so that the production period is shortened, and the energy consumption and the labor cost are reduced; meanwhile, the precoated sand process has relatively low requirements on materials, so that the selection of raw materials is more flexible, and the production cost is further reduced; meanwhile, the precoated sand technology is small in occupied area and small in environmental pollution, and meets the modern environmental protection requirement; according to the precoated sand technology, less waste is generated in the production process, the influence on the environment is smaller, green production is facilitated, the bucket tooth produced through the precoated sand technology is subjected to heat treatment, the mechanical property and the abrasion resistance of the bucket tooth are further improved, and the bucket tooth better meets the use requirement of a super-huge excavator.

Description

Technical Field

[0001] The invention relates to the technical field of excavator bucket tooth preparation, in particular to an excavator bucket tooth and a forming process. Background Art

[0002] In large-scale mining operations, super-large excavators weighing more than 50 tons play a vital role. The bucket teeth used in these excavators are parts that directly contact the ore, and their performance is directly related to the excavation efficiency and equipment maintenance costs. However, the existing bucket tooth production process and material selection face multiple challenges.

[0003] The working environment of bucket teeth of super-large excavators is extremely harsh, and they need to withstand huge impact forces, wear and complex geological conditions. In order to meet such high-intensity working requirements, the material of bucket teeth usually has a higher hardness to ensure sufficient wear resistance and impact resistance. However, the increase in hardness is often accompanied by a decrease in toughness, which makes bucket teeth prone to batch fracture during use, especially when subjected to large impact forces. On the contrary, if the material hardness is reduced in order to improve toughness, the wear resistance of the bucket teeth will be greatly reduced, and it will not be able to meet the needs of long-term efficient excavation.

[0004] At present, it is difficult to produce bucket teeth for extra-large excavators. The main reason is the limitation of production process. The existing production mainly adopts forging and water glass sand process. Although the traditional forging process can produce bucket teeth with relatively balanced performance, it has low production efficiency, high cost, and high requirements on materials, and it is difficult to adapt to the needs of large-scale production. Although the water glass sand process reduces the production cost to a certain extent, it occupies a large area and causes serious environmental pollution, which is not conducive to environmental protection and production. Therefore, an excavator bucket tooth and forming process are proposed. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an excavator bucket tooth and a forming process to solve the background technical problems.

[0006] In the first aspect, in order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: an excavator bucket tooth, which comprises the following groups in terms of mass percentage based on the total mass of the bucket tooth:

[0007] Carbon (C) is used to adjust the hardness and strength of the material, accounting for 0.25%-0.30%;

[0008] Silicon (Si) is used to improve the corrosion resistance and heat resistance of materials, accounting for 1.2%-1.5%;

[0009] Manganese (Mn) is used to enhance the toughness and wear resistance of the material, accounting for 1.0%-1.25%;

[0010] Chromium (Cr) is used to increase the hardness and corrosion resistance of the material, accounting for 1.20%-1.45%;

[0011] Molybdenum (Mo) helps to improve the strength and creep resistance of the material, accounting for ≥0.15%;

[0012] Nickel (Ni) is used to improve the corrosion resistance and heat resistance of materials, accounting for ≤0.25%;

[0013] Sulfur (S) is used to improve the cutting performance of steel, accounting for ≤0.015%;

[0014] Phosphorus (P), used to improve the strength and hardness of steel, accounting for ≤0.025%;

[0015] The balance is Fe and inevitable impurities.

[0016] An excavator bucket tooth according to claim 2, characterized in that the bucket tooth has a tensile strength (MPA) ≥ 1500 MPA, an elongation (%) ≥ 2%, and a Brinell hardness of 435-510 HBW.

[0017] A second aspect: A forming process for an excavator bucket tooth, comprising the excavator bucket tooth according to any one of the first aspects, wherein the forming process for the excavator bucket tooth is:

[0018] Raw material preparation: Conduct general inspection on raw materials, and prepare the qualified raw materials according to the mass percentage;

[0019] Mould preparation: According to the shape and size of the bucket teeth, prepare a coated sand mould that meets the accuracy, put it into the sand box, fill it and vibrate it;

[0020] Melting: Put the raw materials prepared according to the mass percentage into the melting furnace for melting to obtain uniform molten steel;

[0021] Casting: Cast the molten steel into the coated sand mold in the sand box, take the coated sand mold out of the sand box after cooling, separate the casting from the coated sand mold, and obtain the initial shape of the bucket tooth;

[0022] First grinding: Grind the surface of the bucket teeth to remove surface impurities and burrs;

[0023] Heat treatment: heat treatment of the grinded bucket teeth, including quenching and tempering;

[0024] Secondary grinding: The bucket teeth after heat treatment are subjected to secondary grinding to remove the oxide scale on the surface, and then cleaned to ensure that the surface of the bucket teeth is clean and free of impurities;

[0025] Painting: The cleaned bucket teeth are painted to improve their corrosion resistance and aesthetics. After painting, they are dried and packaged for storage.

[0026] Preferably, the quenching temperature in the heat treatment process is 850-950°C, the holding time is 1-2 hours, and then oil cooling or water cooling is performed; the tempering temperature is 500-650°C, the holding time is 2-4 hours, and then air cooling or water cooling is performed.

[0027] Preferably, the first grinding and the second grinding steps both use a shot blasting machine to grind the bucket tooth surface, and the diameter of the grinding shot is in the range of 0.15-0.2 mm.

[0028] Preferably, the casting riser of the coated sand mold is staggered with the stress concentration point of the bucket tooth.

[0029] Preferably, the painting step includes spraying of primer and topcoat, the primer is used to improve the adhesion and rust resistance of the bucket teeth, and the topcoat is used to improve the aesthetics and weather resistance of the bucket teeth, and after the primer is sprayed, a drying treatment is performed first and then the topcoat is sprayed, and after the topcoat is sprayed, another drying treatment is performed.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention accurately proportions the materials for preparing the bucket teeth to ensure that the performance after preparation meets the requirements of large excavators. At the same time, the coated sand process is used to prepare the bucket teeth for large excavators, which significantly improves production efficiency and reduces production costs. The coated sand process does not require complicated mold preparation and high-temperature forging processes, thereby shortening the production cycle and reducing energy consumption and labor costs. At the same time, the coated sand process has relatively low requirements on materials, making the selection of raw materials more flexible and further reducing production costs. At the same time, the coated sand process occupies a small area and has little environmental pollution, which meets modern environmental protection requirements. The coated sand process generates less waste in the production process, has less impact on the environment, and is conducive to achieving green production. By heat treating the bucket teeth produced by the coated sand process, their mechanical properties and wear resistance are further improved, making them more suitable for the use requirements of extra-large excavators.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flowchart of the excavator bucket tooth forming process. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this technical field without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1: This embodiment provides an excavator bucket tooth, which includes the following groups in terms of mass percentage based on the total mass of the bucket tooth:

[0036] The carbon (C) content is 0.25%-0.30%; in this embodiment, the carbon content is preferably 0.28%. As a basic element of steel materials, an appropriate amount of carbon content can significantly improve the hardness and strength of the material.

[0037] Silicon (Si) accounts for 1.2%-1.5%; in this embodiment, the silicon accounted for 1.2%. Silicon can effectively improve the corrosion resistance and heat resistance of steel, especially in high temperature and humid environments, can effectively prevent material corrosion and extend the service life of bucket teeth.

[0038] Manganese (Mn) accounts for 1.0%-1.25%; in this embodiment, the manganese accounted for 1.2%. Manganese element enhances the toughness and wear resistance of steel by forming a solid solution, making the bucket teeth more durable when subjected to impact and wear.

[0039] Chromium (Cr) accounts for 1.20%-1.45%; in this embodiment, the chromium accounted for 1.4% preferably. Chromium is a key element for improving the hardness and corrosion resistance of steel, and can form a dense oxide film on the surface of the material to resist erosion by the external environment.

[0040] The molybdenum (Mo) content is ≥ 0.15%; in this embodiment, the chromium content is preferably 0.18%. The molybdenum element helps to improve the strength and creep resistance of the steel, and can effectively prevent deformation and softening of the material, especially under high temperature conditions.

[0041] The nickel (Ni) content is ≤ 0.25%; in this embodiment, the nickel content is preferably 0.25%. The nickel element can also improve the corrosion resistance and heat resistance of the material, especially in an acidic or alkaline environment, showing excellent corrosion resistance.

[0042] The sulfur (S) content is ≤ 0.015%; in this embodiment, the sulfur content is preferably 0.013%. Sulfur is generally regarded as a harmful element in steel because it reduces the toughness and corrosion resistance of the steel. However, in the bucket teeth, the addition of sulfur can form sulfide inclusions, thereby improving the cutting performance of the steel. However, in order to ensure that the performance of the steel is not affected by it, its content is controlled to be relatively low.

[0043] Phosphorus (P) accounts for ≤0.025%; in this embodiment, the phosphorus accounted for preferably 0.02%. Phosphorus is also regarded as a harmful element in steel because it reduces the plasticity and toughness of steel. Then, in the bucket teeth, the addition of phosphorus can play a role of solid solution strengthening, which can improve the strength and hardness of steel. However, in order to ensure that the performance of the steel is not affected by it, its content is controlled to be relatively low.

[0044] The balance is Fe and inevitable impurities.

[0045] Based on the above materials, the prepared bucket teeth have a tensile strength (MPA) ≥ 1500MPA, an elongation (%) ≥ 2%, and a Brinell hardness of 435-510HBW.

[0046] Embodiment 2:

[0047] On the basis of the first embodiment, this embodiment provides a forming process for an excavator bucket tooth, and the forming process for the excavator bucket tooth is as follows:

[0048] Step 1: Raw material preparation

[0049] Raw materials must undergo strict general inspection, including chemical composition analysis, physical property testing, etc., to ensure that the quality of raw materials meets the standards;

[0050] Use a high-precision electronic scale to accurately weigh the raw materials after general inspection, and prepare each raw material according to the mass percentage of Example 1 to ensure that the ratio is accurate.

[0051] Step 2: Mold preparation

[0052] Preparation of coated sand mold:

[0053] Selection of coated sand: High-quality coated sand is the basis for preparing high-quality molds. Coated sand is mainly composed of quartz sand, thermoplastic phenolic resin and curing agent. Quartz sand, as aggregate, provides the hardness and strength of the mold; resin and curing agent form the bonding layer of the mold to ensure the stability and durability of the mold during the casting process;

[0054] Mixing of raw materials: Mix quartz sand, resin and curing agent in a certain proportion to ensure that each grain of sand is fully wrapped by the resin; during the mixing process, control the mixing temperature and time to avoid premature curing of the resin.

[0055] Mould design and production:

[0056] Conversion of three-dimensional drawings: According to the three-dimensional drawings of the bucket teeth, use CAD / CAM software to perform three-dimensional modeling of the mold; during the modeling process, it is necessary to fully consider the shape, size and casting process requirements of the bucket teeth to ensure that the accuracy and size of the mold meet the requirements. During the design process, it is considered that the riser position during mold casting needs to be staggered with the stress concentration point of the bucket teeth, where the stress concentration point includes the sharp corners, edges or connection parts of the bucket teeth.

[0057] Production of mold prototype: Use CNC engraving machine or 3D printing technology to make a mold prototype based on the three-dimensional model; CNC engraving machine carves the shape of the mold on the material by accurately controlling the movement trajectory of the tool; while 3D printing technology directly prints the entity of the mold by stacking materials layer by layer.

[0058] Mold replication and processing: After obtaining the mold prototype, multiple molds are made through replication and processing. During the replication process, it is necessary to ensure that the size and shape of each mold are consistent with the prototype. During the processing process, the mold needs to be trimmed and polished as necessary to meet the requirements of the casting process.

[0059] Quality inspection of molds:

[0060] Dimension measurement: Use precise measuring tools to measure the dimensions of the mold to ensure that the accuracy and dimensions of the mold meet the design requirements;

[0061] Surface finish inspection: Check the surface finish of the mold visually or using tools such as a microscope to ensure that the mold surface is free of defects and impurities;

[0062] Strength test: Perform strength test on the mold to ensure that the mold can withstand the pressure and impact of molten steel without deformation or cracking during the casting process.

[0063] Mold placement and compaction:

[0064] Placement of mold: Place the prepared mold in the sand box; during the placement process, ensure that the mold is in the correct position and in the same direction;

[0065] Use a vibrating table to compact: Use a vibrating table to compact the sand box; the vibrating table generates high-frequency vibration waves to rearrange and tightly contact the coated sand particles around the mold to form a dense sand mold; during the compaction process, the vibration frequency and time need to be controlled to avoid damage to the mold due to excessive impact force, so as to achieve stable restriction of the mold.

[0066] Inspection and adjustment: After compaction, check the mold to ensure that the sand mold is compact and free of defects.

[0067] Step 3: Melting

[0068] The raw materials prepared according to the mass percentage are put into the melting furnace for melting to obtain uniform molten steel; the melting furnace adopts a medium-frequency induction furnace to ensure that the molten steel has a uniform temperature and consistent composition.

[0069] Step 4: Casting

[0070] After smelting is completed, use a casting machine to pour the molten steel quickly and smoothly into the coated sand mold to avoid bubbles and inclusions; after casting is completed, let the casting cool naturally to room temperature, then take the mold out of the sand box, separate the casting and the mold, and get the initial shape of the bucket tooth; when the molten steel is out of the furnace and when the molten steel in the casting machine is almost used up, the molten steel is inspected and controlled to ensure that it is free of lumps, impurities, and has sufficient fluidity.

[0071] Step 5: Finished product screening

[0072] The obtained preliminary bucket teeth are tested for weight, appearance, internal structure and performance;

[0073] Weight detection:

[0074] Use accurate weighing equipment to weigh each bucket tooth to ensure that its weight meets the design requirements. Excessive weight deviation may mean uneven material or problems in the casting process;

[0075] Visual inspection:

[0076] Visual inspection: First, conduct a visual inspection to see if there are any obvious cracks, pores, inclusions or other defects on the surface of the bucket teeth. These defects may affect the strength and wear resistance of the bucket teeth.

[0077] Dimension measurement: Use image analysis technology to measure the size of the bucket teeth to ensure that they meet the design requirements; dimensional deviation may cause poor fit between the bucket teeth and other parts of the excavator, affecting the use effect.

[0078] Internal quality inspection:

[0079] Non-destructive testing: Sampling the produced bucket teeth, using ultrasonic testing, X-ray testing and other non-destructive testing methods to check whether there are defects such as cracks and pores inside the bucket teeth; these internal defects may affect the strength and durability of the bucket teeth.

[0080] Performance Test:

[0081] Hardness test: Sampling the produced bucket teeth and conducting hardness tests to ensure that their hardness meets the design requirements. Insufficient hardness may cause the bucket teeth to wear quickly during use;

[0082] Impact test: Sampling the produced bucket teeth for impact test to evaluate the impact resistance of the bucket teeth, which helps to ensure that the bucket teeth can still maintain good performance under harsh working conditions.

[0083] Step 6: First polishing

[0084] Use a shot blasting machine to grind the surface of the bucket teeth to remove surface impurities, burrs and oxide scale to improve surface finish;

[0085] The shot blasting machine uses a 2mm shot blasting wheel to ensure that the shot blasting force and coverage meet the requirements.

[0086] Step 7: Heat treatment

[0087] Quenching: put the bucket teeth into a quenching furnace, heat to 850-950℃, keep warm for 1-2 hours, and then oil or water cool to improve the hardness and strength of the material;

[0088] Tempering: Put the quenched bucket teeth into the tempering furnace, heat to 500-650℃, keep warm for 2-4 hours, and then air-cool or water-cool to eliminate quenching stress and improve the toughness and plasticity of the material;

[0089] During the heat treatment process, the heating temperature, holding time and cooling speed should be strictly controlled to ensure the best heat treatment effect.

[0090] Step 8: Secondary polishing

[0091] Use the shot blasting machine to grind the bucket teeth again to remove the oxide scale and surface defects generated during the heat treatment process and further improve the surface quality; the shot blasting machine uses a 1.5mm shot blasting wheel to ensure that the shot blasting force and coverage meet the requirements and perform fine grinding;

[0092] After grinding, use a high-pressure air gun or vacuum cleaner to clean the surface of the bucket teeth to ensure that no impurities remain.

[0093] Step 9: Spray paint

[0094] Primer spraying: Use a spray gun to evenly spray the primer on the surface of the bucket teeth. The primer should have good adhesion and anti-rust properties;

[0095] Primer drying: Put the bucket teeth sprayed with primer into the drying room and heat them to a certain temperature to make the primer dry and solidify quickly;

[0096] Topcoat spraying: After the primer is completely dry, use a spray gun to evenly spray the topcoat on the surface of the bucket teeth. The topcoat should have good aesthetics and weather resistance;

[0097] Topcoat drying: Put the topcoat-sprayed bucket teeth into the drying room again and heat them to a certain temperature to make the topcoat dry and solidify quickly;

[0098] After drying, the bucket teeth are inspected for quality, including appearance inspection, size measurement, etc., to ensure that they meet standard requirements.

[0099] Step 10: Packing and storage

[0100] Pack qualified bucket teeth in special packaging boxes or pallets to ensure they are not damaged during transportation and storage;

[0101] After packaging, the bucket teeth are placed in the warehouse for inventory management and wait for shipment.

[0102] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An excavator bucket tooth, characterized in that: The total mass of the bucket teeth includes the following groups in percentage by mass: Carbon (C) is used to adjust the hardness and strength of the material, accounting for 0.25%-0.30%; Silicon (Si) is used to improve the corrosion resistance and heat resistance of materials, accounting for 1.2%-1.5%; Manganese (Mn) is used to enhance the toughness and wear resistance of the material, accounting for 1.0%-1.25%; Chromium (Cr) is used to increase the hardness and corrosion resistance of the material, accounting for 1.20%-1.45%; Molybdenum (Mo) helps to improve the strength and creep resistance of the material, accounting for ≥0.15%; Nickel (Ni) is used to improve the corrosion resistance and heat resistance of materials, accounting for ≤0.25%; Sulfur (S) is used to improve the cutting performance of steel, accounting for ≤0.015%; Phosphorus (P), used to improve the strength and hardness of steel, accounting for ≤0.025%; The balance is Fe and inevitable impurities.

2. The excavator bucket tooth according to claim 1, characterized in that: The bucket tooth has a tensile strength (MPA) of ≥1500 MPA, an elongation (%) of ≥2%, and a Brinell hardness of 435-510 HBW.

3. A process for forming bucket teeth for excavators, characterized in that: The excavator bucket tooth comprises the excavator bucket tooth according to any one of claims 1 and 2, wherein the forming process of the excavator bucket tooth is: Raw material preparation: Conduct general inspection on raw materials, and prepare the qualified raw materials according to the mass percentage; Mould preparation: According to the shape and size of the bucket teeth, prepare a coated sand mould that meets the accuracy, put it into the sand box, fill it and vibrate it; Melting: Put the raw materials prepared according to the mass percentage into the melting furnace for melting to obtain uniform molten steel; Casting: Cast the molten steel into the coated sand mold in the sand box, take the coated sand mold out of the sand box after cooling, separate the casting from the coated sand mold, and get the initial shape of the bucket tooth; First grinding: Grind the surface of the bucket teeth to remove surface impurities and burrs; Heat treatment: heat treatment of the grinded bucket teeth, including quenching and tempering; Secondary grinding: The bucket teeth after heat treatment are subjected to secondary grinding to remove the oxide scale on the surface, and then cleaned to ensure that the surface of the bucket teeth is clean and free of impurities; Painting: The cleaned bucket teeth are painted to improve their corrosion resistance and aesthetics. After painting, they are dried and packaged for storage.

4. The excavator bucket tooth forming process according to claim 3, characterized in that: The quenching temperature in the heat treatment process is 850-950°C, the holding time is 1-2 hours, and then oil cooling or water cooling is performed; the tempering temperature is 500-650°C, the holding time is 2-4 hours, and then air cooling or water cooling is performed.

5. The excavator bucket tooth forming process according to claim 3, characterized in that: The first grinding and the second grinding steps both use a shot blasting machine to grind the bucket tooth surface, and the diameter of the grinding projectile ranges from 0.15 to 0.2 mm.

6. The excavator bucket tooth forming process according to claim 3, characterized in that: The casting riser of the coated sand mold is staggered with the stress concentration point of the bucket tooth.

7. The excavator bucket tooth forming process according to claim 3, characterized in that: The painting step includes spraying of primer and topcoat, wherein the primer is used to improve the adhesion and rust resistance of the bucket teeth, and the topcoat is used to improve the aesthetics and weather resistance of the bucket teeth. After the primer is sprayed, a drying process is performed first and then the topcoat is sprayed, and after the topcoat is sprayed, another drying process is performed.

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