Preparation method of large thick-wall hard alloy mixture

Abstract

The invention discloses a preparation method of a large thick-wall hard alloy mixture. The preparation method comprises the following steps that 1, various raw materials needed for preparing the mixture are put into a 300-liter tilting-type ball mill to be subjected to ball milling; step 2, the slurry is sieved by a 325-mesh sieve, and the sieved slurry is put into a large barrel to be precipitated for 24 hours; step 3, putting the precipitated slurry of which the absolute ethyl alcohol on the surface is filtered out into a 300-liter vertical stirring dryer, and drying for 4-6 hours; cooling to room temperature after the powder is dried; step 4, continuing to mix the rubber forming agent in the vertical stirring dryer; and step 5, filling inert gas into the material barrel filled with the mixed material doped with the glue for protection, then lifting the feeding cover for discharging, sieving, sampling and detecting, and packaging qualified products into the barrel. All operations including drying, glue mixing, drying and the like can be completed on the same equipment.

Description

Technical Field

[0001] The invention relates to the technical field of cemented carbide manufacturing, in particular to a method for preparing a thick-walled cemented carbide mixture. Background Art

[0002] There are two main methods for preparing cemented carbide mixtures:

[0003] 1. Ball milling → precipitation → vacuum drying → sieving → adding 20% ​​glue (glue mixing machine) → sieving → drying → sieving → inspection;

[0004] 2. Ball milling → spray drying → sieving → adding 20% ​​glue (glue mixing machine) → sieving → drying → sieving → inspection.

[0005] The above preparation method has the following defects:

[0006] High oxygen content and low efficiency;

[0007] The equipment cost is high, not suitable for rubber technology, and it takes a long time to clean the machine when changing brands;

[0008] The material has too much glue, the degumming time is too long and it is not clean, the product carbon is unbalanced, the product internal stress is large, and the product cracks.

[0009] It cannot be used for the production of thick-walled products.

[0010] The information disclosed in the above background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0011] In view of the above existing defects, the present invention aims to provide a method for preparing a thick-walled cemented carbide mixture. By mixing the mixture in a vacuum environment, the mixture has a low oxygen content, no doping, uniform glue content, more uniform powder, higher quality and more stable.

[0012] To achieve the above object, the present invention adopts the following technical solutions:

[0013] A method for preparing a thick-walled cemented carbide mixture comprises the following steps:

[0014] Step 1, various raw materials required for preparing the mixture are put into a 300-liter tilting ball mill for ball milling, 1200 kg of grinding balls and 65-85 liters of ball milling medium anhydrous ethanol are added, and the ball milling is carried out for 20-108 hours;

[0015] Step 2: Pass the slurry through a 325-mesh screen into a large bucket and let it settle for 24 hours;

[0016] Step 3, the precipitated slurry after filtering out the anhydrous ethanol on the surface is placed in a 300-liter vertical stirring dryer for 4-6 hours of drying; after the powder is dried, the temperature is lowered to room temperature;

[0017] Step 4, continue to add the rubber forming agent in the vertical stirring dryer, fill the barrel containing the dried mixed material with inert gas for protection, then raise the loading cover and add 480 ml / kg of rubber forming agent at one time, then evacuate, heat while stirring, wait until the mixed material is evenly mixed with rubber, gasoline, etc. are completely volatilized, and then cool to room temperature;

[0018] Step 5: Fill the barrel with the mixed material after adding glue with inert gas for protection, then lift the cover to discharge the material, sieve, take samples for testing, and pack and barrel the qualified materials.

[0019] Furthermore, the inert gas is nitrogen.

[0020] Furthermore, the component percentages of the mixture are as follows: WC-84%~86%, Co-12%~13%, Ni-2%~3%, Cr3C2-0.5%~0.7%.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The process is consistent and efficient. All operations such as drying, glue mixing, and drying can be completed on the same equipment;

[0023] 2. Save labor costs, shorten the time by 4 hours / batch, improve powder utilization, reduce the dust exposure hazards to operators, and reduce dependence on manual labor;

[0024] 3. The production of the mixture is completed in a vacuum environment and under constant stirring. The mixture has low oxygen content, no doping, uniform glue content, more uniform powder, higher and more stable quality.

[0025] 4. The production of this kind of mixture expands the scope of cemented carbide production, provides more convenient conditions for the production of thick-walled or solid cylinders and plates, ensures molding and shaping, and shortens the degumming time by 80%. The products produced are whiter in appearance and have better performance.

[0026] 5. It eliminates the hidden danger of internal carbon imbalance caused by unclean debonding, especially for products with thick walls, so that the carbon content inside and outside the product is balanced, eliminating product cracks, solving the subsequent wire cutting, wire walking and other processing methods of cemented carbide, and further increases the problem of product cracking and bursting caused by large internal stress of cemented carbide products, and further improves the product's bending strength and impact toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of a 300-liter tilting ball mill according to the present invention.

[0028] Figure 2 This is a diagram of a thick-walled cemented carbide product according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the embodiments and accompanying drawings. In the description of this embodiment, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0030] Example 1

[0031] A method for preparing a thick-walled cemented carbide mixture comprises the following steps:

[0032] Step 1, 4500 kg of various raw materials with weight percentages of WC-85.3%, Co-12%, Ni-2%, and Cr3C2-0.7% are put into a 300-liter tilting ball mill for ball milling, 1200 kg of grinding balls and 65 liters of ball milling medium anhydrous ethanol are added, and the ball milling is carried out for 20 hours;

[0033] Step 2: Pass the slurry through a 325-mesh screen into a large bucket and let it settle for 24 hours;

[0034] Step 3, the precipitated slurry after filtering out the anhydrous ethanol on the surface is placed in a 300-liter vertical stirring dryer for 4 hours; after the powder is dried, the temperature is lowered to room temperature;

[0035] Step 4, continue to add the rubber forming agent in the vertical stirring dryer, fill the barrel containing the dried mixed material with nitrogen for protection, then raise the loading cover and add 480 ml / kg of rubber forming agent at one time, then evacuate, heat to 50°C while stirring, stir for 5 hours, wait until the mixed material is evenly mixed with rubber and gasoline and the like are completely volatilized, and then cool to room temperature;

[0036] Step 5: Fill the barrel with the mixed material after adding glue with nitrogen for protection, then lift the cover to discharge the material, sieve, take samples for testing, and pack and barrel the qualified materials.

[0037] Example 2

[0038] A method for preparing a thick-walled cemented carbide mixture comprises the following steps:

[0039] Step 1, 4500 kg of various raw materials with weight percentages of WC-84.5%, Co-13%, Ni-2%, and Cr3C2-0.5% are put into a 300-liter tilting ball mill for ball milling, 1200 kg of grinding balls and 85 liters of ball milling medium anhydrous ethanol are added, and the ball milling is carried out for 108 hours;

[0040] Step 2: Pass the slurry through a 325-mesh screen into a large bucket and let it settle for 24 hours;

[0041] Step 3, the precipitated slurry after filtering out the anhydrous ethanol on the surface is placed in a 300-liter vertical stirring dryer for 4-6 hours of drying; after the powder is dried, the temperature is lowered to room temperature;

[0042] Step 4, continue to add the rubber forming agent in the vertical stirring dryer, fill the barrel containing the dried mixed material with nitrogen for protection, then raise the loading cover and add 480 ml / kg of rubber forming agent at one time, then evacuate, heat to 50°C while stirring, stir for 6 hours, wait until the mixed material is evenly mixed with rubber and gasoline and other materials are completely volatilized, and then cool to room temperature;

[0043] Step 5: Fill the barrel with the mixed material after adding glue with nitrogen for protection, then lift the cover to discharge the material, sieve, take samples for testing, and pack and barrel the qualified materials.

[0044] Example 3

[0045] A method for preparing a thick-walled cemented carbide mixture comprises the following steps:

[0046] Step 1, 4500 kg of various raw materials with weight percentages of WC-84.3%, Co-12%, Ni-3%, and Cr3C2-0.7% are put into a 300-liter tilting ball mill for ball milling, 1200 kg of grinding balls and 705 liters of ball milling medium anhydrous ethanol are added, and the ball milling is carried out for 30 hours;

[0047] Step 2: Pass the slurry through a 325-mesh screen into a large bucket and let it settle for 24 hours;

[0048] Step 3, the precipitated slurry after filtering out the anhydrous ethanol on the surface is placed in a 300-liter vertical stirring dryer for 5 hours; after the powder is dried, the temperature is lowered to room temperature;

[0049] Step 4, continue to add the rubber forming agent in the vertical stirring dryer, fill the barrel containing the dried mixed material with nitrogen for protection, then raise the loading cover and add 480 ml / kg of rubber forming agent at one time, then evacuate, heat to 45°C while stirring, stir for 12 hours, wait until the mixed material is evenly mixed with rubber and gasoline and other materials are completely volatilized, and then cool to room temperature;

[0050] Step 5: Fill the barrel with the mixed material after adding glue with nitrogen for protection, then lift the cover to discharge the material, sieve, take samples for testing, and pack and barrel the qualified materials.

[0051] Example 4

[0052] A method for preparing a thick-walled cemented carbide mixture comprises the following steps:

[0053] Step 1, 4500 kg of various raw materials with weight percentages of WC-85%, Co-12%, Ni-2.5%, and Cr3C2-0.5% are put into a 300-liter tilting ball mill for ball milling, 1200 kg of grinding balls and 85 liters of ball milling medium anhydrous ethanol are added, and the ball milling is carried out for 108 hours;

[0054] Step 2: Pass the slurry through a 325-mesh screen into a large bucket and let it settle for 24 hours;

[0055] Step 3, the precipitated slurry after filtering out the anhydrous ethanol on the surface is placed in a 300-liter vertical stirring dryer for 4-6 hours of drying; after the powder is dried, the temperature is lowered to room temperature;

[0056] Step 4, continue to add the rubber forming agent in the vertical stirring dryer, fill the barrel containing the dried mixed material with nitrogen for protection, then raise the loading cover and add 480 ml / kg of rubber forming agent at one time, then evacuate, heat to 45°C while stirring, stir for 8 hours, wait until the mixed material is evenly mixed with rubber and gasoline and the like are completely volatilized, and then cool to room temperature;

[0057] Step 5: Fill the barrel with the mixed material after adding glue with nitrogen for protection, then lift the cover to discharge the material, sieve, take samples for testing, and pack and barrel the qualified materials.

[0058] Experimental example

[0059] The hard alloy mixtures prepared in Examples 1-4 are made into Figure 2 The thick-walled cemented carbide products shown have a wall thickness of more than 500mm. The bending strength, impact toughness and grain size of the products are tested as follows:

[0060]

[0061]

[0062] From the experimental measurements of the bending strength, impact toughness and grain size of thick-walled products, it can be seen that the mixing method of the present invention is used for the mixture, the mixture has low oxygen content, is free of doping, has uniform glue content, has more uniform powder, and has higher and more stable quality.

[0063] The method of the present invention has a coherent process and high efficiency. It can be automatically controlled by a computer and all operations such as drying + glue mixing + drying can be completed on the same device. It saves labor costs, shortens the time by 4 hours / batch, improves the utilization rate of powder, reduces the dust contact hazard to operators, and reduces dependence on labor. The production of the mixture is completed in a vacuum environment and under a state of constant stirring. The mixture has low oxygen content, no doping, uniform glue content, more uniform powder, and higher and more stable quality. The production of this kind of mixture expands the scope of cemented carbide production, provides more convenient conditions for the production of thick-walled or large solid cylinders and plates, ensures molding and shaping, and shortens the degumming time by 80%. The products produced have a whiter appearance and better performance. It eliminates the hidden danger of internal carbon imbalance caused by unclean debonding, especially in products with thick walls, so that the carbon content inside and outside the product is balanced, eliminating product cracks, and solving the subsequent wire cutting, wire walking and other processing methods of cemented carbide. It further increases the problem of cracking and bursting of cemented carbide products due to large internal stress, and improves the bending strength and impact toughness of the product.

[0064] Although the present invention has been described in detail above with specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for preparing a thick-walled cemented carbide mixture, characterized in that: The following steps are included Step 1, various raw materials required for preparing the mixture are put into a 300-liter tilting ball mill for ball milling, 1200 kg of grinding balls and 65-85 liters of ball milling medium anhydrous ethanol are added, and the ball milling is carried out for 20-108 hours; Step 2: Pass the slurry through a 325-mesh screen into a large bucket and let it settle for 24 hours; Step 3, the precipitated slurry after filtering out the anhydrous ethanol on the surface is placed in a 300-liter vertical stirring dryer for 4-6 hours; the powder is cooled to room temperature after drying; Step 4, continue to add the rubber forming agent in the vertical stirring dryer, fill the barrel containing the dried mixed material with inert gas for protection, then raise the loading cover and add 480 ml / kg of rubber forming agent at one time, then evacuate, heat while stirring, wait until the mixed material is evenly mixed with rubber, gasoline, etc. are completely volatilized, and then cool to room temperature; Step 5: Fill the barrel with the mixed material after adding glue with inert gas for protection, then lift the cover to discharge the material, sieve, take samples for testing, and pack and barrel the qualified materials.

2. The method for preparing a thick-walled cemented carbide mixture according to claim 1, characterized in that: The inert gas is nitrogen.

3. The method for preparing a thick-walled cemented carbide mixture according to claim 1, characterized in that: The component percentages of the mixture are as follows: WC-84% to 86%, Co-12% to 13%, Ni-2% to 3%, Cr3C2-0.5% to 0.7%.

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