CN104399983A - Method for reducing bending rate of hard alloy short bar materials - Google Patents

Abstract

The invention discloses a method for reducing the bending rate of cemented carbide short rods. The process steps include: a. pressing; b. drying the blank naturally; c. degumming; d. putting the blank loaded by the graphite boat into a vacuum In the sintering furnace, vacuumize after closing the furnace door; e, vacuum primary sintering; f, the billet is cooled to room temperature with the furnace; g, on the surface of the V-shaped groove of the graphite cover plate and the V-shaped groove surface of the bottom plate of the graphite bottom plate Apply anti-adhesive coating; h, anti-adhesive coating is dried naturally; i, sinter loaded graphite boat to load the blank; j, put the blank loaded by sintered graphite boat into the vacuum sintering furnace, and vacuumize after closing the furnace door processing; k, vacuum forming and sintering; l, the finished product is cooled to room temperature with the furnace; m, cutting. Through the design of the above process steps, the present invention can effectively reduce the bending rate of the short cemented carbide rod and effectively avoid the sticking phenomenon, that is, it can effectively improve the quality and yield of the short cemented carbide rod.

Description

A Method for Reducing Bending Rate of Hard Alloy Short Rods

technical field

The invention relates to the technical field of cemented carbide sintering processing, in particular to a method for reducing the bending rate of cemented carbide short rods.

Background technique

Cemented carbide is an alloy material made of hard compounds of refractory metals and bonding metals through powder metallurgy; cemented carbide has high hardness, wear resistance, good strength and toughness, heat resistance, corrosion resistance, etc. A series of excellent properties, especially its high hardness and wear resistance, remain basically unchanged even at a temperature of 500 ° C, and still have high hardness at 1000 ° C. With the above excellent properties, cemented carbide is widely used in tool materials, such as turning tools, milling cutters, planers, drills, boring tools, etc.

In addition, for cemented carbide, it generally includes refractory metal compounds and bonding metals, such as cobalt and nickel; in the cemented carbide processing industry, as an important sintering equipment, vacuum carbon tube sintering Furnaces are widely used; for cemented carbide, in the actual sintering process, the cemented carbide workpiece is easily bonded to the graphite boat used to hold the workpiece, causing the workpiece to be scrapped.

It should be further pointed out that in the process of vacuum sintering of cemented carbide workpieces in a vacuum sintering furnace, especially for short cemented carbide rods, due to the shrinkage phenomenon in the vacuum sintering process and the longer the rod, the less bent, The shorter the bar is, the easier it is to bend. The one-time bending pass rate of the hard alloy short bar processed by the existing technology is not more than 70%, and the bent hard alloy short bar needs to pass through one or more times. Re-sintering correction treatment increases the cost and reduces the quality.

Contents of the invention

The purpose of the present invention is to provide a kind of method that reduces the bending rate of cemented carbide short bar for the deficiencies in the prior art, and the method for reducing the bending rate of cemented carbide short bar can effectively reduce the bending of cemented carbide short bar It is efficient and can effectively avoid the bonding phenomenon that occurs during vacuum sintering, that is, it can effectively improve the quality and yield of cemented carbide short rods.

In order to achieve the above object, the present invention is achieved through the following technical solutions.

1. A method for reducing the bending rate of cemented carbide short rods, characterized in that, comprising the following process steps, specifically:

a. Putting the cemented carbide raw materials mixed uniformly and mixed with glue into the extruder, and the extruder prepares a round cemented carbide bar blank through a forming die;

b. Place the tungsten carbide round bar blank in a graphite boat and dry it naturally in a ventilated environment; wherein, the graphite boat is in the shape of a rectangular thin plate, and the upper surface of the graphite boat is provided with a A V-shaped groove extending in the length direction and having a V-shaped cross section. The lower surface of the graphite boat is a smooth structure. The length of the graphite boat is 1000mm-1200mm. The round carbide rod blank is placed on the V of the graphite boat. inside the groove;

c. Put the natural-dried hard alloy round bar blank into the degumming furnace along with the graphite boat, and after closing the furnace door of the degumming furnace, pass hydrogen gas into the degumming furnace and carry out the hydrogen blowing operation for 30 minutes , after the ignition test is confirmed to be qualified, the hydrogen outlet of the degumming furnace is ignited and the degumming operation is carried out. Continue to keep warm for 30 minutes under the temperature condition. After the heat preservation is completed, the degumming furnace is powered off and the carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen;

d. Put the degummed and cooled cemented carbide round bar blank into the vacuum sintering furnace along with the graphite boat. After closing the furnace door of the vacuum sintering furnace, vacuumize the vacuum sintering furnace so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.1 Torr-1 Torr;

e. After the vacuuming operation is completed, start to heat up and carry out a vacuum sintering operation. First, the temperature is raised from room temperature to 600 degrees, and the heating time is 2 hours; when the temperature reaches 600 degrees, the temperature is raised from 600 degrees to 950 degrees -1050 degrees, and keep warm for 30 minutes at a temperature of 950 degrees to 1050 degrees;

f. After the continuous heat preservation is completed at a temperature of 950-1050 degrees, the vacuum sintering furnace is powered off, and the carbide round bar blank is cooled to room temperature with the furnace while maintaining the vacuum;

g. The sintered loaded graphite boat is coated with an anti-sticking coating. The anti-sticking coating is a mixture of industrial alcohol, carbon black powder and alumina powder. Wherein, the sintered loaded graphite boat includes a graphite bottom plate and a graphite cover The upper surface of the graphite base plate is provided with a V-shaped groove extending along the length of the graphite base plate and having a V-shaped cross-section. The lower surface of the graphite base plate is a smooth structure, and the lower surface of the graphite cover plate is provided with a The cover plate extends in the length direction and has a V-shaped groove in the cross-section. The upper surface of the graphite cover plate is a smooth structure, and the anti-sticking coating is evenly coated on the surface of the V-shaped groove of the graphite base plate and the graphite cover plate. The V-groove surface of the cover plate;

h. Place the graphite bottom plate and graphite cover plate coated with anti-sticking paint in a ventilated environment for natural drying;

i. Place the cemented carbide round bar blank after vacuum primary sintering in the bottom V-shaped groove of the graphite bottom plate, then install the graphite cover plate directly above the graphite bottom plate and ensure that the bottom plate V-shaped groove of the graphite bottom plate is in line with the graphite bottom plate. The V-groove of the cover plate of the graphite cover plate is aligned so that the round carbide rod blank is just clamped between the V-shaped groove of the bottom plate of the graphite base plate and the V-shaped groove of the cover plate of the graphite cover plate, and finally on the graphite cover plate. Carbide briquetting blocks are evenly placed on the upper surface of the plate, so that the graphite cover plate faces down to press the tungsten carbide round bar blank;

j. Put the sintered graphite boat with tungsten carbide round rod blank into the vacuum sintering furnace, and vacuumize the vacuum sintering furnace after closing the furnace door of the vacuum sintering furnace, so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.1 Torr-1 Torr;

k. After the vacuuming operation is completed, start to heat up and carry out vacuum forming and sintering operations. First, the temperature is raised from room temperature to 1050 degrees, and the heating time is 2 hours; The time is 1 hour and the temperature is kept at 1450 degrees for 30 minutes;

l. After the continuous heat preservation at a temperature of 1450 degrees, the power of the vacuum sintering furnace is cut off, and the round carbide rod blank is cooled to room temperature with the furnace while maintaining the vacuum degree, and the round carbide rod is prepared. ;

m. Cut the finished hard alloy round bar into short hard alloy bars with a length of less than 40mm by a wire electric discharge machine.

Wherein, in the step c, the degumming furnace first heats up to 500-550 degrees at a heating rate of 15 degrees/hour-30 degrees/hour, and continues to keep warm for 30 minutes at a temperature of 500-550 degrees. After the completion, the degumming furnace is powered off and the carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen.

Wherein, in the step c, the degumming furnace first heats up to 500 degrees at a heating rate of 30 degrees per hour, and continues to keep warm for 30 minutes at a temperature of 500 degrees. After the heat preservation is completed, the degumming furnace is powered off and the cemented carbide The round bar blanks were naturally cooled to room temperature under the protection of hydrogen.

Wherein, in the step d, the vacuum degree of the inner cavity of the vacuum sintering furnace after vacuuming reaches 0.3 Torr-0.7 Torr.

Wherein, in the step d, the vacuum degree of the inner chamber of the vacuum sintering furnace after vacuuming reaches 0.5 Torr.

Wherein, in the step j, the vacuum degree of the inner chamber of the vacuum sintering furnace after vacuuming reaches 0.3 Torr-0.7 Torr.

Wherein, in the step j, the vacuum degree of the inner cavity of the vacuum sintering furnace after vacuuming reaches 0.5 Torr.

Wherein, the anti-stick coating is prepared by mixing 900ml-1100ml of industrial alcohol, 80g-120g of carbon black powder, and 160g-240g of aluminum oxide powder.

Wherein, the anti-stick coating is formed by mixing 1000ml of industrial alcohol, 100g of carbon black powder, and 200g of aluminum oxide powder.

The beneficial effect of the present invention is: a kind of method for reducing the bending rate of cemented carbide short bar according to the present invention, its process step comprises: a, hard alloy circular bar blank press forming; b, graphite boat loading The blanks are dried naturally; c. Place the blanks loaded by the graphite boat in the degumming furnace for degumming treatment; d. Put the blanks loaded by the graphite boat into the vacuum sintering furnace, and vacuumize after closing the furnace door ; E, the vacuum sintering furnace performs vacuum primary sintering on the billet; f, after the vacuum primary sintering is completed, the billet is cooled to room temperature with the furnace; g, on the surface of the V-shaped groove of the graphite cover plate and the V-shaped groove surface of the bottom plate of the graphite base plate Apply anti-adhesive coating; h, anti-adhesive coating is dried naturally; i, the sintered loading graphite boat loads the blank, and the blank is clamped between the V-shaped groove of the bottom plate and the V-shaped groove of the cover plate; j, loads the graphite boat loaded by sintering Put the billet into the vacuum sintering furnace, close the furnace door and carry out vacuum treatment; k, the vacuum sintering furnace performs vacuum forming and sintering on the billet; l, after the vacuum sintering is completed, cool down to room temperature with the furnace, The material is prepared; m. The electric discharge wire cutting machine cuts the finished hard alloy round bar into a hard alloy short bar. Through the design of the above process steps, the present invention can effectively reduce the bending rate of the short cemented carbide rod and can effectively avoid the bonding phenomenon that occurs during vacuum sintering, that is, it can effectively improve the quality of the short cemented carbide rod and Yield.

Detailed ways

The present invention will be described below in conjunction with specific embodiments.

Embodiment 1, a method for reducing the bending rate of cemented carbide short rods includes the following process steps, specifically:

a. Putting the cemented carbide raw materials mixed uniformly and mixed with glue into the extruder, and the extruder prepares a round cemented carbide bar blank through a forming die;

b. Place the tungsten carbide round bar blank in a graphite boat and dry it naturally in a ventilated environment; wherein, the graphite boat is in the shape of a rectangular thin plate, and the upper surface of the graphite boat is provided with a A V-shaped groove extending in the length direction and having a V-shaped cross section. The lower surface of the graphite boat is a smooth structure. The length of the graphite boat is 1000mm-1200mm. The round carbide rod blank is placed on the V of the graphite boat. inside the groove;

c. Put the natural-dried hard alloy round bar blank into the degumming furnace along with the graphite boat, and after closing the furnace door of the degumming furnace, pass hydrogen gas into the degumming furnace and carry out the hydrogen blowing operation for 30 minutes After the ignition test confirms that it is qualified, ignite the hydrogen outlet of the degumming furnace and carry out the degumming operation. The degumming furnace first heats up to 500 degrees at a heating rate of 30 degrees per hour, and continues to keep warm at 500 degrees for 30 minutes. After the completion, the degumming furnace is powered off and the tungsten carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen;

d. Put the degummed and cooled cemented carbide round bar blank into the vacuum sintering furnace along with the graphite boat. After closing the furnace door of the vacuum sintering furnace, vacuumize the vacuum sintering furnace so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.5 Torr;

e. After the vacuuming operation is completed, start to heat up and carry out a vacuum sintering operation. First, the temperature is raised from room temperature to 600 degrees, and the heating time is 2 hours; when the temperature reaches 600 degrees, the temperature is raised from 600 degrees to 950 degrees -1050 temperature (selected differently according to the diameter of the carbide round bar blank, the larger the diameter, the higher the selected temperature value), and keep warm for 30 minutes at a temperature of 950-1050 degrees;

f. After the continuous heat preservation is completed at a temperature of 950-1050 degrees, the vacuum sintering furnace is powered off, and the carbide round bar blank is cooled to room temperature with the furnace while maintaining the vacuum;

g. The sintered loaded graphite boat is coated with an anti-sticking coating. The anti-sticking coating is a mixture of industrial alcohol, carbon black powder and alumina powder. Wherein, the sintered loaded graphite boat includes a graphite bottom plate and a graphite cover The upper surface of the graphite base plate is provided with a V-shaped groove extending along the length of the graphite base plate and having a V-shaped cross-section. The lower surface of the graphite base plate is a smooth structure, and the lower surface of the graphite cover plate is provided with a The cover plate extends in the length direction and has a V-shaped groove in the cross-section. The upper surface of the graphite cover plate is a smooth structure, and the anti-sticking coating is evenly coated on the surface of the V-shaped groove of the graphite base plate and the graphite cover plate. The V-groove surface of the cover plate;

h. Place the graphite bottom plate and graphite cover plate coated with anti-sticking paint in a ventilated environment for natural drying;

i. Place the cemented carbide round bar blank after vacuum primary sintering in the bottom V-shaped groove of the graphite bottom plate, then install the graphite cover plate directly above the graphite bottom plate and ensure that the bottom plate V-shaped groove of the graphite bottom plate is in line with the graphite bottom plate. The V-groove of the cover plate of the graphite cover plate is aligned so that the round carbide rod blank is just clamped between the V-shaped groove of the bottom plate of the graphite base plate and the V-shaped groove of the cover plate of the graphite cover plate, and finally on the graphite cover plate. Carbide briquetting blocks are evenly placed on the upper surface of the plate, so that the graphite cover plate faces down to press the tungsten carbide round bar blank;

j. Put the sintered graphite boat with tungsten carbide round rod blank into the vacuum sintering furnace, and vacuumize the vacuum sintering furnace after closing the furnace door of the vacuum sintering furnace, so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.5 Torr;

k. After the vacuuming operation is completed, start to heat up and carry out vacuum forming and sintering operations. First, the temperature is raised from room temperature to 1050 degrees, and the heating time is 2 hours; The time is 1 hour and the temperature is kept at 1450 degrees for 30 minutes;

l. After the continuous heat preservation at a temperature of 1450 degrees, the power of the vacuum sintering furnace is cut off, and the round carbide rod blank is cooled to room temperature with the furnace while maintaining the vacuum degree, and the round carbide rod is prepared. ;

m. Cut the finished hard alloy round bar into short hard alloy bars with a length of less than 40mm by a wire electric discharge machine.

It should be further pointed out that the anti-adhesive coating used in the first embodiment is mixed with denatured alcohol 1000ml, carbon black powder 100g, and alumina powder 200g; The alloy round rod blank is bonded to the V-shaped groove surface of the graphite cover plate and the V-shaped groove surface of the bottom plate of the graphite bottom plate, thereby effectively reducing the scrapping phenomenon caused by bonding and improving the quality of the round carbide rod. yield rate.

In addition, during the vacuum sintering process of the cemented carbide round rod blank in the vacuum sintering furnace, since the cemented carbide round rod blank passes through the V-shaped groove of the bottom plate of the graphite bottom plate and the V-shaped groove of the cover plate of the graphite cover plate Clamped and fixed, the structurally designed sintered graphite boat can effectively reduce the curvature of the carbide round rod blank.

It needs to be further explained that when the cemented carbide round rod blank is pressed and dried and enters the degumming furnace for degumming, since there is no need to change the graphite boat and the cemented carbide round rod blank is directly degummed in the original state after pressing, so It can effectively avoid the breakage of the ultra-long carbide round bar blank. In addition, the cemented carbide round bar blank after degumming does not need to be machined, that is, it does not need to be cut off by a diamond grinder, because the strength of the cemented carbide round bar blank after degumming is very low and easy to Fracture, do not process the cutting head and make the cemented carbide round rod blank undergo vacuum primary sintering in the original state after degumming, which can effectively prevent the cemented carbide round rod blank from breaking. In addition, the cemented carbide round rod blank after primary vacuum sintering has sufficient rigidity, which can ensure the smooth progress of graphite boat conversion.

It should be further pointed out that the short cemented carbide rod in the first embodiment is cut from an ultra-long round cemented carbide rod by a wire electric discharge machine, so that the longer the rod, the less curved it can be effectively utilized. The performance characteristics of the cemented carbide short rod can reach 99%.

Based on the above situation, it can be seen that through the design of the above process steps, the method for reducing the curvature of the short cemented carbide rod in the first embodiment can effectively reduce the curvature of the short cemented carbide rod and can effectively avoid the occurrence of vacuum sintering. The bonding phenomenon can effectively improve the quality and yield of cemented carbide short rods.

the

Embodiment 2, a method for reducing the bending rate of cemented carbide short rods, includes the following process steps, specifically:

a. Putting the cemented carbide raw materials mixed uniformly and mixed with glue into the extruder, and the extruder prepares a round cemented carbide bar blank through a forming die;

b. Place the tungsten carbide round bar blank in a graphite boat and dry it naturally in a ventilated environment; wherein, the graphite boat is in the shape of a rectangular thin plate, and the upper surface of the graphite boat is provided with a A V-shaped groove extending in the length direction and having a V-shaped cross section. The lower surface of the graphite boat is a smooth structure. The length of the graphite boat is 1000mm-1200mm. The round carbide rod blank is placed on the V of the graphite boat. inside the groove;

c. Put the natural-dried hard alloy round bar blank into the degumming furnace along with the graphite boat, and after closing the furnace door of the degumming furnace, pass hydrogen gas into the degumming furnace and carry out the hydrogen blowing operation for 30 minutes After the ignition test confirms that it is qualified, ignite the hydrogen outlet of the degumming furnace and carry out the degumming operation. The degumming furnace first heats up to 450 degrees at a rate of 5 degrees per hour, and continues to keep warm at 450 degrees for 30 minutes. After the completion, the degumming furnace is powered off and the tungsten carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen;

d. Put the degummed and cooled cemented carbide round bar blank into the vacuum sintering furnace along with the graphite boat. After closing the furnace door of the vacuum sintering furnace, vacuumize the vacuum sintering furnace so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.1 Torr;

e. After the vacuuming operation is completed, start to heat up and carry out a vacuum sintering operation. First, the temperature is raised from room temperature to 600 degrees, and the heating time is 2 hours; when the temperature reaches 600 degrees, the temperature is raised from 600 degrees to 950 degrees -1050 temperature (selected differently according to the diameter of the carbide round bar blank, the larger the diameter, the higher the selected temperature value), and keep warm for 30 minutes at a temperature of 950-1050 degrees;

f. After the continuous heat preservation is completed at a temperature of 950-1050 degrees, the vacuum sintering furnace is powered off, and the carbide round bar blank is cooled to room temperature with the furnace while maintaining the vacuum;

g. The sintered loaded graphite boat is coated with an anti-sticking coating. The anti-sticking coating is a mixture of industrial alcohol, carbon black powder and alumina powder. Wherein, the sintered loaded graphite boat includes a graphite bottom plate and a graphite cover The upper surface of the graphite base plate is provided with a V-shaped groove extending along the length of the graphite base plate and having a V-shaped cross-section. The lower surface of the graphite base plate is a smooth structure, and the lower surface of the graphite cover plate is provided with a The cover plate extends in the length direction and has a V-shaped groove in the cross-section. The upper surface of the graphite cover plate is a smooth structure, and the anti-sticking coating is evenly coated on the surface of the V-shaped groove of the graphite base plate and the graphite cover plate. The V-groove surface of the cover plate;

h. Place the graphite bottom plate and graphite cover plate coated with anti-sticking paint in a ventilated environment for natural drying;

i. Place the cemented carbide round bar blank after vacuum primary sintering in the bottom V-shaped groove of the graphite bottom plate, then install the graphite cover plate directly above the graphite bottom plate and ensure that the bottom plate V-shaped groove of the graphite bottom plate is in line with the graphite bottom plate. The V-groove of the cover plate of the graphite cover plate is aligned so that the round carbide rod blank is just clamped between the V-shaped groove of the bottom plate of the graphite base plate and the V-shaped groove of the cover plate of the graphite cover plate, and finally on the graphite cover plate. Carbide briquetting blocks are evenly placed on the upper surface of the plate, so that the graphite cover plate faces down to press the tungsten carbide round bar blank;

j. Put the sintered graphite boat with tungsten carbide round rod blank into the vacuum sintering furnace, and vacuumize the vacuum sintering furnace after closing the furnace door of the vacuum sintering furnace, so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.1 Torr;

k. After the vacuuming operation is completed, start to heat up and carry out vacuum forming and sintering operations. First, the temperature is raised from room temperature to 1050 degrees, and the heating time is 2 hours; The time is 1 hour and the temperature is kept at 1450 degrees for 30 minutes;

l. After the continuous heat preservation at a temperature of 1450 degrees, the power of the vacuum sintering furnace is cut off, and the round carbide rod blank is cooled to room temperature with the furnace while maintaining the vacuum degree, and the round carbide rod is prepared. ;

m. Cut the finished hard alloy round bar into short hard alloy bars with a length of less than 40mm by a wire electric discharge machine.

It should be further pointed out that the anti-adhesive coating used in the first embodiment is mixed with denatured alcohol 900ml, carbon black powder 80g, and alumina powder 160g; The alloy round rod blank is bonded to the V-shaped groove surface of the graphite cover plate and the V-shaped groove surface of the bottom plate of the graphite bottom plate, thereby effectively reducing the scrapping phenomenon caused by bonding and improving the quality of the round carbide rod. yield rate.

In addition, during the vacuum sintering process of the cemented carbide round rod blank in the vacuum sintering furnace, since the cemented carbide round rod blank passes through the V-shaped groove of the bottom plate of the graphite bottom plate and the V-shaped groove of the cover plate of the graphite cover plate Clamped and fixed, the structurally designed sintered graphite boat can effectively reduce the curvature of the carbide round rod blank.

It needs to be further explained that when the cemented carbide round rod blank is pressed and dried and enters the degumming furnace for degumming, since there is no need to change the graphite boat and the cemented carbide round rod blank is directly degummed in the original state after pressing, so It can effectively avoid the breakage of the ultra-long carbide round bar blank. In addition, the cemented carbide round bar blank after degumming does not need to be machined, that is, it does not need to be cut off by a diamond grinder, because the strength of the cemented carbide round bar blank after degumming is very low and easy to Fracture, do not process the cutting head and make the cemented carbide round rod blank undergo vacuum primary sintering in the original state after degumming, which can effectively prevent the cemented carbide round rod blank from breaking. In addition, the cemented carbide round rod blank after primary vacuum sintering has sufficient rigidity, which can ensure the smooth progress of graphite boat conversion.

It should be further pointed out that the short cemented carbide rod in the second embodiment is cut from the ultra-long round cemented carbide rod by a wire electric discharge machine, so that the longer the rod, the less curved it can be effectively utilized. The performance characteristics of the cemented carbide short rod can reach 99%.

Based on the above situation, it can be seen that through the design of the above process steps, the method for reducing the curvature of the short cemented carbide rod in the second embodiment can effectively reduce the curvature of the short cemented carbide rod and can effectively avoid the occurrence of vacuum sintering. The bonding phenomenon can effectively improve the quality and yield of cemented carbide short rods.

the

Embodiment 3, a method for reducing the bending rate of a short hard alloy rod includes the following process steps, specifically:

a. Putting the cemented carbide raw materials mixed uniformly and mixed with glue into the extruder, and the extruder prepares a round cemented carbide bar blank through a forming die;

b. Place the tungsten carbide round bar blank in a graphite boat and dry it naturally in a ventilated environment; wherein, the graphite boat is in the shape of a rectangular thin plate, and the upper surface of the graphite boat is provided with a A V-shaped groove extending in the length direction and having a V-shaped cross section. The lower surface of the graphite boat is a smooth structure. The length of the graphite boat is 1000mm-1200mm. The round carbide rod blank is placed on the V of the graphite boat. inside the groove;

c. Put the natural-dried hard alloy round bar blank into the degumming furnace along with the graphite boat, and after closing the furnace door of the degumming furnace, pass hydrogen gas into the degumming furnace and carry out the hydrogen blowing operation for 30 minutes , after the ignition test confirms that it is qualified, ignite the hydrogen outlet of the degumming furnace and carry out the degumming operation. The degumming furnace first heats up to 550 degrees at a heating rate of 30 degrees per hour, and continues to keep warm at 550 degrees for 30 minutes. After the completion, the degumming furnace is powered off and the tungsten carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen;

d. Put the degummed and cooled cemented carbide round bar blank into the vacuum sintering furnace along with the graphite boat. After closing the furnace door of the vacuum sintering furnace, vacuumize the vacuum sintering furnace so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 1 torr;

e. After the vacuuming operation is completed, start to heat up and carry out a vacuum sintering operation. First, the temperature is raised from room temperature to 600 degrees, and the heating time is 2 hours; when the temperature reaches 600 degrees, the temperature is raised from 600 degrees to 950 degrees -1050 temperature (selected differently according to the diameter of the carbide round bar blank, the larger the diameter, the higher the selected temperature value), and keep warm for 30 minutes at a temperature of 950-1050 degrees;

f. After the continuous heat preservation is completed at a temperature of 950-1050 degrees, the vacuum sintering furnace is powered off, and the carbide round bar blank is cooled to room temperature with the furnace while maintaining the vacuum;

g. The sintered loaded graphite boat is coated with an anti-sticking coating. The anti-sticking coating is a mixture of industrial alcohol, carbon black powder and alumina powder. Wherein, the sintered loaded graphite boat includes a graphite bottom plate and a graphite cover The upper surface of the graphite base plate is provided with a V-shaped groove extending along the length of the graphite base plate and having a V-shaped cross-section. The lower surface of the graphite base plate is a smooth structure, and the lower surface of the graphite cover plate is provided with a The cover plate extends in the length direction and has a V-shaped groove in the cross-section. The upper surface of the graphite cover plate is a smooth structure, and the anti-sticking coating is evenly coated on the surface of the V-shaped groove of the graphite base plate and the graphite cover plate. The V-groove surface of the cover plate;

h. Place the graphite bottom plate and graphite cover plate coated with anti-sticking paint in a ventilated environment for natural drying;

i. Place the cemented carbide round bar blank after vacuum primary sintering in the bottom V-shaped groove of the graphite bottom plate, then install the graphite cover plate directly above the graphite bottom plate and ensure that the bottom plate V-shaped groove of the graphite bottom plate is in line with the graphite bottom plate. The V-groove of the cover plate of the graphite cover plate is aligned so that the round carbide rod blank is just clamped between the V-shaped groove of the bottom plate of the graphite base plate and the V-shaped groove of the cover plate of the graphite cover plate, and finally on the graphite cover plate. Carbide briquetting blocks are evenly placed on the upper surface of the plate, so that the graphite cover plate faces down to press the tungsten carbide round bar blank;

j. Put the sintered graphite boat with tungsten carbide round rod blank into the vacuum sintering furnace, and vacuumize the vacuum sintering furnace after closing the furnace door of the vacuum sintering furnace, so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 1 torr;

k. After the vacuuming operation is completed, start to heat up and carry out vacuum forming and sintering operations. First, the temperature is raised from room temperature to 1050 degrees, and the heating time is 2 hours; The time is 1 hour and the temperature is kept at 1450 degrees for 30 minutes;

l. After the continuous heat preservation at a temperature of 1450 degrees, the power of the vacuum sintering furnace is cut off, and the round carbide rod blank is cooled to room temperature with the furnace while maintaining the vacuum degree, and the round carbide rod is prepared. ;

m. Cut the finished hard alloy round bar into short hard alloy bars with a length of less than 40mm by a wire electric discharge machine.

It should be further pointed out that the anti-adhesive coating used in the first embodiment is mixed with denatured alcohol 1100ml, carbon black powder 120g, and alumina powder 240g; wherein, the anti-adhesive coating can effectively avoid hard The alloy round rod blank is bonded to the V-shaped groove surface of the graphite cover plate and the V-shaped groove surface of the bottom plate of the graphite bottom plate, thereby effectively reducing the scrapping phenomenon caused by bonding and improving the quality of the round carbide rod. yield rate.

In addition, during the vacuum sintering process of the cemented carbide round rod blank in the vacuum sintering furnace, since the cemented carbide round rod blank passes through the V-shaped groove of the bottom plate of the graphite bottom plate and the V-shaped groove of the cover plate of the graphite cover plate Clamped and fixed, the structurally designed sintered graphite boat can effectively reduce the curvature of the carbide round rod blank.

It needs to be further explained that when the cemented carbide round rod blank is pressed and dried and enters the degumming furnace for degumming, since there is no need to change the graphite boat and the cemented carbide round rod blank is directly degummed in the original state after pressing, so It can effectively avoid the breakage of the ultra-long carbide round bar blank. In addition, the cemented carbide round bar blank after degumming does not need to be machined, that is, it does not need to be cut off by a diamond grinder, because the strength of the cemented carbide round bar blank after degumming is very low and easy to Fracture, do not process the cutting head and make the cemented carbide round rod blank undergo vacuum primary sintering in the original state after degumming, which can effectively prevent the cemented carbide round rod blank from breaking. In addition, the cemented carbide round rod blank after primary vacuum sintering has sufficient rigidity, which can ensure the smooth progress of graphite boat conversion.

It should be further pointed out that the short cemented carbide rod in the third embodiment is cut from the ultra-long round cemented carbide rod by a wire electric discharge machine, so that the longer the rod, the less curved it can be effectively utilized. The performance characteristics of the cemented carbide short rod can reach 99%.

Based on the above situation, it can be seen that through the design of the above process steps, the method for reducing the curvature of the short cemented carbide rod in the third embodiment can effectively reduce the curvature of the short cemented carbide rod and can effectively avoid the phenomenon that occurs during vacuum sintering. The bonding phenomenon can effectively improve the quality and yield of cemented carbide short rods.

The above content is only a preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. limits.

Claims (9)

1. A method for reducing the bending rate of cemented carbide short bar, is characterized in that, comprises following processing steps, specifically: a. Putting the cemented carbide raw materials mixed uniformly and mixed with glue into the extruder, and the extruder prepares a round cemented carbide bar blank through a forming die; b. Place the tungsten carbide round bar blank in a graphite boat and dry it naturally in a ventilated environment; wherein, the graphite boat is in the shape of a rectangular thin plate, and the upper surface of the graphite boat is provided with a A V-shaped groove extending in the length direction and having a V-shaped cross section. The lower surface of the graphite boat is a smooth structure. The length of the graphite boat is 1000mm-1200mm. The round carbide rod blank is placed on the V of the graphite boat. inside the groove; c. Put the natural-dried hard alloy round bar blank into the degumming furnace along with the graphite boat, and after closing the furnace door of the degumming furnace, pass hydrogen gas into the degumming furnace and carry out the hydrogen blowing operation for 30 minutes , after the ignition test is confirmed to be qualified, the hydrogen outlet of the degumming furnace is ignited and the degumming operation is carried out. Continue to keep warm for 30 minutes under the temperature condition. After the heat preservation is completed, the degumming furnace is powered off and the carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen; d. Put the degummed and cooled cemented carbide round bar blank into the vacuum sintering furnace along with the graphite boat. After closing the furnace door of the vacuum sintering furnace, vacuumize the vacuum sintering furnace so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.1 Torr-1 Torr; e. After the vacuuming operation is completed, start to heat up and carry out a vacuum sintering operation. First, the temperature is raised from room temperature to 600 degrees, and the heating time is 2 hours; when the temperature reaches 600 degrees, the temperature is raised from 600 degrees to 950 degrees -1050 degrees, and keep warm for 30 minutes at a temperature of 950 degrees to 1050 degrees; f. After the continuous heat preservation is completed at a temperature of 950-1050 degrees, the vacuum sintering furnace is powered off, and the carbide round bar blank is cooled to room temperature with the furnace while maintaining the vacuum; g. The sintered loaded graphite boat is coated with an anti-sticking coating. The anti-sticking coating is a mixture of industrial alcohol, carbon black powder and alumina powder. Wherein, the sintered loaded graphite boat includes a graphite bottom plate and a graphite cover The upper surface of the graphite base plate is provided with a V-shaped groove extending along the length of the graphite base plate and having a V-shaped cross-section. The lower surface of the graphite base plate is a smooth structure, and the lower surface of the graphite cover plate is provided with a The cover plate extends in the length direction and has a V-shaped groove in the cross-section. The upper surface of the graphite cover plate is a smooth structure, and the anti-sticking coating is evenly coated on the surface of the V-shaped groove of the graphite base plate and the graphite cover plate. The V-groove surface of the cover plate; h. Place the graphite bottom plate and graphite cover plate coated with anti-sticking paint in a ventilated environment for natural drying; i. Place the cemented carbide round bar blank after vacuum primary sintering in the bottom V-shaped groove of the graphite bottom plate, then install the graphite cover plate directly above the graphite bottom plate and ensure that the bottom plate V-shaped groove of the graphite bottom plate is in line with the graphite bottom plate. The V-groove of the cover plate of the graphite cover plate is aligned so that the round carbide rod blank is just clamped between the V-shaped groove of the bottom plate of the graphite base plate and the V-shaped groove of the cover plate of the graphite cover plate, and finally on the graphite cover plate. Carbide briquetting blocks are evenly placed on the upper surface of the plate, so that the graphite cover plate faces down to press the tungsten carbide round bar blank; j. Put the sintered graphite boat with tungsten carbide round rod blank into the vacuum sintering furnace, and vacuumize the vacuum sintering furnace after closing the furnace door of the vacuum sintering furnace, so that the vacuum sintering furnace The vacuum degree of the inner cavity reaches 0.1 Torr-1 Torr; k. After the vacuuming operation is completed, start to heat up and carry out vacuum forming and sintering operations. First, the temperature is raised from room temperature to 1050 degrees, and the heating time is 2 hours; The time is 1 hour and the temperature is kept at 1450 degrees for 30 minutes; l. After the continuous heat preservation at a temperature of 1450 degrees, the power of the vacuum sintering furnace is cut off, and the round carbide rod blank is cooled to room temperature with the furnace while maintaining the vacuum degree, and the round carbide rod is prepared. ; m. Cut the finished hard alloy round bar into short hard alloy bars with a length of less than 40mm by a wire electric discharge machine. 2. A method for reducing the bending rate of cemented carbide short rods according to claim 1, characterized in that: in said step c, the degumming furnace is first heated at a rate of 15 degrees/hour-30 degrees/hour Raise the temperature to 500-550 degrees, and keep warm for 30 minutes at the temperature of 500-550 degrees. After the heat preservation is completed, the degumming furnace is powered off and the tungsten carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen. 3. A method for reducing the bending rate of cemented carbide short rods according to claim 2, characterized in that: in said step c, the degumming furnace is first heated to 500 degrees at a heating rate of 30 degrees/hour, Continue to keep warm for 30 minutes at a temperature of 500 degrees. After the heat preservation is completed, the degumming furnace is powered off and the tungsten carbide round bar blank is naturally cooled to room temperature under the protection of hydrogen. 4. A method for reducing the bending rate of cemented carbide short rods according to claim 3, characterized in that: in said step d, the vacuum degree of the vacuum sintering furnace cavity after vacuuming reaches 0.3 torr- 0.7 torr. 5. A method for reducing the bending rate of cemented carbide short rods according to claim 4, characterized in that: in the step d, the vacuum degree of the inner chamber of the vacuum sintering furnace after vacuuming reaches 0.5 Torr. 6. A method for reducing the bending rate of cemented carbide short rods according to claim 5, characterized in that: in said step j, the vacuum degree of the vacuum sintering furnace cavity after vacuuming reaches 0.3 Torr- 0.7 torr. 7. A method for reducing the bending rate of cemented carbide short rods according to claim 6, characterized in that: in the step j, the vacuum degree of the inner chamber of the vacuum sintering furnace after vacuuming reaches 0.5 Torr. 8. A method for reducing the bending rate of cemented carbide short rods according to any one of claims 1 to 7, characterized in that: the anti-stick coating is composed of denatured alcohol 900ml-1100ml, carbon black powder 80g-120g , Aluminum oxide powder 160g-240g mixed. 9. A method for reducing the bending rate of cemented carbide short rods according to claim 8, characterized in that: the anti-adhesive coating is formed by mixing 1000ml of denatured alcohol, 100g of carbon black powder, and 200g of alumina powder.