Method for improving the magnetic saturation of a cemented carbide tool tip

Abstract

The present application relates to hard alloy tool bit processing technical field, disclose a kind of method for improving the magnetic saturation of hard alloy tool bit, comprising: taking liquid paint appropriately, it is evenly applied on boat dish;The boat dish that has been applied paint is heated to completely dry;Hard alloy tool bit is placed on boat dish;The boat dish with hard alloy tool bit is placed into vacuum sintering furnace;Control sintering temperature and holding time, and according to the carbon content required by hard alloy tool bit select corresponding sintering temperature and holding time;After holding, cool to room temperature and discharge, obtain the hard alloy tool bit that magnetic saturation is promoted and uniform.The present application can guarantee the magnetic saturation of hard alloy tool bit reaches normal standard, with the advantages of low production cost, high production efficiency, safe and stable and reliable.

Description

Technical Field

[0001] This invention relates to the field of cemented carbide cutting tool technology, and in particular to a method for improving the magnetic saturation of cemented carbide cutting tools used in construction. Background Technology

[0002] Hard alloys are alloy materials made from hard carbides of refractory metals and binder metals through powder metallurgy. Due to their excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance, especially their high strength and wear resistance, hard alloys are widely used in industries such as construction engineering, mining and oil drilling, machining, and aerospace.

[0003] In the machining of cemented carbide, magnetic saturation is a critical quality control indicator. The control range of magnetic saturation varies even for the same cemented carbide grade depending on its application. Therefore, controlling the magnetic saturation of cemented carbide is crucial. The machining process of cemented carbide is complex, and improper control of factors such as carbon content, forming agent dosage, oxygen content, furnace vacuum level, and air humidity can all lead to excessively low or high magnetic saturation. When the magnetic saturation of cemented carbide exceeds the control standard for that grade, these products are considered scrap, resulting in a decrease in product yield and a sharp increase in production costs.

[0004] Currently, there are two methods to improve magnetic saturation during cemented carbide machining: CN108637248A and CN106637052B. CN108637248A improves the magnetic saturation of the product before alloying during cemented carbide production; however, this method cannot solve the problem of low magnetic saturation after alloying. While CN106637052B can improve the low magnetic saturation after cemented carbide machining, its production cost is high, the process is complex, and the use of a CH4 methane gas atmosphere for sintering results in a low safety factor.

[0005] Therefore, improvements are needed. Summary of the Invention

[0006] The technical problem solved by this invention is to address the deficiencies in the prior art by providing a method for improving the magnetic saturation of cemented carbide cutting tools. Its main purpose is to provide a method with low production cost, higher safety factor, and higher production efficiency to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for improving the magnetic saturation of cemented carbide cutting tools, comprising: taking an appropriate amount of liquid coating and uniformly applying it to a boat, wherein the liquid coating comprises, by mass fraction, 15-25% high-pigment carbon black, 2-4% polyethylene glycol, 6-8% Tween 80, 1.5-2.5% n-butanol, and 60-75% deionized water; heating the boat coated with the coating until completely dry; and then applying the cemented carbide cutting tool to the boat. The carbide cutting tips are evenly placed on a coated boat, ensuring that each tip is in contact with the coating. The boat containing the carbide cutting tips is then placed in a vacuum sintering furnace and heated from room temperature to 1250℃-1350℃, holding for 150-250 minutes. The sintering temperature and holding time are controlled, and the appropriate sintering temperature and holding time are selected according to the required carbon content of the carbide cutting tips. After the holding time, the tips are cooled to room temperature and removed from the furnace to obtain carbide cutting tips with enhanced and uniform magnetic saturation.

[0008] Furthermore, the thickness of the liquid coating on the boat is 0.2–0.8 mm.

[0009] Compared with existing technologies, the advantages of this invention are as follows: Compared with existing methods of atmosphere sintering, this invention has lower production costs, higher production efficiency, and is safer, more stable, and more reliable. At the same time, it ensures that the magnetic saturation of the carbide cutting tip reaches the normal standard, avoiding product scrap. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the results of Example 1.

[0011] Figure 2 This is a schematic diagram of the results of Example 2.

[0012] Figure 3 This is a schematic diagram of the results of Example 3.

[0013] Figure 4 This is a schematic diagram of the results of Example 4.

[0014] Figure 5 This is a schematic diagram of the results of Example 5.

[0015] Figure 6 This is a schematic diagram of the results of Example 6.

[0016] Figure 7 This is a schematic diagram of the results of Example 7.

[0017] Figure 8 This is a schematic diagram of the results of Example 8.

[0018] Figure 9 This is a schematic diagram of the results of Example 9.

[0019] Figure 10This is a schematic diagram of the results of Example 10. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings.

[0021] The embodiments described with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "several" or "more than" means two or more, unless otherwise explicitly specified. In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In this application, unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or it can include contact between the first and second features through another feature between them. Moreover, "above," "over," and "on top" of a second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] A method for improving the magnetic saturation of cemented carbide cutting tools for construction includes:

[0023] Take an appropriate amount of liquid coating and evenly apply it to a boat. The liquid coating includes, by mass fraction: 15-25% high-pigment carbon black, 2-4% polyethylene glycol, 6-8% Tween 80, 1.5-2.5% n-butanol, and 60-75% deionized water. Heat the coated boat until completely dry. Place the carbide cutting tips evenly on the coated boat, ensuring that each tip is in contact with the coating. Place the boat containing the carbide cutting tips into a vacuum sintering furnace and heat from room temperature to 1250℃-1350℃, holding for 150-250 minutes. Control the sintering temperature and holding time, selecting the appropriate sintering temperature and holding time according to the required carbon content of the carbide cutting tips. After holding, cool to room temperature and remove from the furnace to obtain carbide cutting tips with enhanced and uniform magnetic saturation.

[0024] Since sintering temperature, holding time, and coating composition are factors that enhance magnetic saturation, a table showing the relationship between the increase in carbon content of cemented carbide and sintering temperature and holding time was derived based on multiple experimental data. This table represents the relationship between the increase in magnetic saturation and sintering temperature and holding time. Then, based on the carbon content requirements of cemented carbide, i.e., the magnetic saturation requirements, the required sintering temperature and holding time were determined from the table showing the relationship between the increase in magnetic saturation and sintering temperature and holding time.

[0025] The core of this method is to improve the magnetic saturation of cemented carbide cutting tips by absorbing carbon from the coating during prolonged holding at liquidus temperatures. First, the cemented carbide cutting tips are placed on a boat coated with the coating, ensuring each tip is in contact with the coating. The boat containing the cutting tips is then placed in a vacuum sintering furnace, heated to 1250℃-1350℃ and held. At this temperature, the alloy is in a WC + liquid cobalt two-phase region. Carbon atoms diffuse from the surface to the core through the liquid cobalt. Because the coating continuously provides diffuseable carbon, simultaneous carburizing and diffusion are achieved, resulting in a uniform carbon distribution within the alloy. This improves the magnetic saturation of the cemented carbide cutting tips. Since carbon diffusion is slow, the appearance of the graphite phase can be controlled by adjusting the carbon diffusion time. Finally, the material is cooled to room temperature before being removed from the furnace. The use of liquid coating ensures uniform adhesion of the coating components to the boat, and the subsequent heating and drying evaporates the moisture in the coating, preventing oxidation of the product.

[0026] Compared with existing atmosphere sintering methods, this invention has lower production costs, higher production efficiency, and is safer, more stable, and more reliable. It also ensures that the magnetic saturation of the carbide cutting tip reaches the normal standard, avoiding product scrap.

[0027] Example 1: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 20%, polyethylene glycol: 4%, Tween 80: 6%, n-butanol: 2%, deionized water: 68%. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0028] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance tungsten carbide, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively; were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1250℃ and held for 150 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 1 .

[0029] Example 2: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 20%, polyethylene glycol: 4%, Tween 80: 6%, n-butanol: 2%, deionized water: 68%. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0030] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance tungsten carbide, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively; were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1300℃ and held for 150 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 2 .

[0031] Example 3: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 20%, polyethylene glycol: 4%, Tween 80: 6%, n-butanol: 2%, deionized water: 68%. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0032] The following cemented carbide cutting tips were prepared with the following composition: Co: 8%, balance tungsten carbide, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively. These tips were placed on coated trays and placed in a vacuum sintering furnace. The furnace temperature was raised from room temperature to 1350℃ and held for 150 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded cemented carbide cutting tips with improved magnetic saturation. Figure 3 .

[0033] Example 4: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 20%, polyethylene glycol: 4%, Tween 80: 6%, n-butanol: 2%, deionized water: 68%. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0034] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance tungsten carbide, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively; were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1250℃ and held for 250 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 4 .

[0035] Example 5: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 20%, polyethylene glycol: 4%, Tween 80: 6%, n-butanol: 2%, deionized water: 68%. Apply the coating evenly to a boat dish to a thickness of 0.5 mm. Place the boat dish in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0036] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance tungsten carbide, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively; were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1300℃ and held for 250 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 5 .

[0037] Example 6: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 20%, polyethylene glycol: 4%, Tween 80: 6%, n-butanol: 2%, deionized water: 68%. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0038] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance tungsten carbide, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively; were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1350℃ and held for 250 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 6 .

[0039] Example 7: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 15%, polyethylene glycol: 2.5%, Tween 80: 6%, n-butanol: 1.5%, and the remainder being deionized water. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0040] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance WC, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively, were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1250℃ and held for 150 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 7 .

[0041] Example 8: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 25%, polyethylene glycol: 4%, Tween 80: 8%, n-butanol: 2.5%, and the remainder being deionized water. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0042] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance WC, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively, were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1250℃ and held for 150 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tips with improved magnetic saturation. Figure 8 .

[0043] Example 9: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 25%, polyethylene glycol: 4%, Tween 80: 8%, n-butanol: 2.5%, and the remainder being deionized water. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0044] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance WC, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively, were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1350℃ and held for 250 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tip products with improved magnetic saturation. Figure 9 .

[0045] Example 10: Take an appropriate amount of liquid coating with the following composition by mass percentage: high-pigment carbon black: 25%, polyethylene glycol: 4%, Tween 80: 8%, n-butanol: 2.5%, and the remainder being deionized water. Apply the coating evenly to a boat to a thickness of 0.5 mm. Place the boat in a drying oven and heat it to 100°C to ensure the coating is completely dry.

[0046] Construction-grade cemented carbide cutting tips with the following composition: Co: 8%, balance WC, and magnetic saturation levels of 72.5%, 73.7%, 75%, 76.2%, and 77.5% respectively, were placed on coated boats and placed in a vacuum sintering furnace. The furnace was heated from room temperature to 1350℃ and held for 250 minutes. After holding, the temperature was cooled to room temperature before being removed from the furnace. This yielded construction-grade cemented carbide cutting tip products with improved magnetic saturation. Figure 10 .

[0047] The above does not limit the technical scope of the present invention in any way. Any modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the technical scope of the present invention.

Claims

1. A method for improving the magnetic saturation of cemented carbide cutting tools for construction, characterized in that, include: Take an appropriate amount of liquid coating and spread it evenly on a boat. The liquid coating includes the following components by mass fraction: high pigment carbon black: 15-25%, polyethylene glycol: 2-4%, Tween 80: 6-8%, n-butanol: 1.5-2.5%, and deionized water: 60-75%. Heat the coated vessel until it is completely dry; Place the carbide cutting tips evenly on the coated tray, ensuring that each carbide cutting tip is in contact with the coating on the tray. Place the boat containing the carbide cutter head into a vacuum sintering furnace and heat it from room temperature to 1250℃-1350℃, holding it at that temperature for 150min-250min. Control the sintering temperature and holding time, and select the appropriate sintering temperature and holding time according to the carbon content required for the cemented carbide cutting tip; After the heat treatment is completed, the material is cooled to room temperature and removed from the furnace to obtain a cemented carbide cutting tip with enhanced and uniform magnetic saturation.

2. The method for improving the magnetic saturation of cemented carbide cutting tools according to claim 1, characterized in that: The thickness of the liquid coating on the vessel is 0.2–0.8 mm.

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