阅读说明：本技术 一种W-Fe-B硬质合金的制备方法 (Preparation method of W-Fe-B hard alloy ) 是由 吕振林 高权 贾磊 张奕豪 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种W-Fe-B硬质合金的制备方法,先将W粉、FeB粉和羰基Fe粉进行混合,压制成块体；最后进行烧结,先将坯体放进真空烧结炉中,设置炉内真空度为10～(-2)Pa,控制加热速率为每分钟10℃,将炉内温度升至1000-1500℃保温1h进行液相烧结,随炉冷却即得到W-Fe-B硬质合金。本发明解决了现有的制备方法加入成型剂不仅会使制备工艺变得繁琐而且会增加粉末污染的机率的问题。(The invention discloses a preparation method of W-Fe-B hard alloy, which comprises the steps of mixing W powder, FeB powder and carbonyl Fe powder, and pressing the mixture into a block; finally sintering, firstly putting the blank into a vacuum sintering furnace, and setting the vacuum degree in the furnace to be 10 ‑2 Pa, controlling the heating rate at 10 ℃ per minute, raising the temperature in the furnace to 1000-1500 ℃, preserving the heat for 1h, carrying out liquid phase sintering, and cooling along with the furnace to obtain the W-Fe-B hard alloy. The invention solves the problems that the preparation process is complicated and the probability of powder pollution is increased by adding the forming agent in the existing preparation method.)

1. the preparation method of the W-Fe-B hard alloy is characterized by comprising the following steps:

step 1, mixing the powders

Taking W powder, FeB powder and carbonyl Fe powder as raw materials, and uniformly mixing in a powder mixer to obtain mixed powder;

step 2, press forming

Putting the mixed powder obtained in the step 1 into a steel die to be pressed and molded to obtain a prefabricated blank;

step 3, sintering the green body

And (3) carrying out pressureless vacuum sintering on the prefabricated blank obtained in the step (2), and cooling to room temperature along with the furnace to obtain a complete W-Fe-B hard alloy blank.

2. The method for preparing the W-Fe-B hard alloy according to the claim 1, wherein the mass ratio of the W to FeB to Fe powder in the step 1 is 40-49: 25-35: 21-24, and mixing.

3. The method of claim 2, wherein the W powder in step 1 has a particle size of 1-5 μm, the carbonyl Fe powder has a particle size of 1-5 μm, and the FeB powder has a particle size of 5-15 μm.

4. The method for preparing W-Fe-B hard alloy according to claim 3, wherein the mass ratio of the balls to the materials in the powder mixer is 1-2:1, the particle size of the grinding balls is 6mm, the frequency of the powder mixer is 50HZ, and the powder mixing time is 1-3 h.

5. The method for preparing W-Fe-B hard alloy according to claim 1, wherein the pressing pressure of the pressing in the step 2 is 300-500MPa, and the pressure holding time is 3-5 min.

6. The method for preparing W-Fe-B hard alloy as claimed in claim 1, wherein the sintering temperature in step 3 is 1000-1500 ℃ and the holding time is 1-2 h.

7. The method for preparing W-Fe-B hard alloy according to claim 6, wherein the vacuum degree in the vacuum sintering furnace in the vacuum sintering in the step 3 is 10^-2Pa, heating rate of 10 deg.C/min.

Technical Field

The invention belongs to the technical field of hard alloys, and relates to a preparation method of a W-Fe-B hard alloy.

Background

The abrasion of the material is widely existed in the service process of key components in the fields of metallurgy, mine, electric power, building materials, energy, traffic and the like, the abrasion not only increases the energy loss, but also shortens the service life of parts, and causes double loss of energy and materials, and 1/3-1/2 energy is wasted every year in the world. The cost of friction, abrasion and the like in the field of friction and abrasion in 2017 in the world is reported to be as high as 210 billion yuan. As a developing country, China lags behind the industry relatively, the consumption in friction and abrasion is more huge, and the metal materials consumed by the friction and the abrasion are more than millions of tons every year. The friction and the abrasion are serious and the rapid development of the national economic society is stopped. Therefore, the active research on the friction and the abrasion of the material and the protection thereof has great economic value.

Borides are considered the most promising metal materials for their high strength, high hardness, high wear resistance, and good thermal conductivity. However, the inherent brittleness and poor sinterability of borides limits their use in industrial applications, and it is these disadvantages that make successful production of transition metal borides difficult. Ternary borides have wide application in numerous fields, particularly in some fields with complex service environments, due to their excellent hardness, wear resistance and corrosion resistance. W-Fe-B alloys have received relatively much attention due to their good wear resistance, remarkable metallurgical bonding properties and outstanding mechanical properties. When many scholars at home and abroad prepare the W-Fe-B, in order to improve the compressibility of the powder, forming agents such as polyvinyl alcohol solution, polyethylene glycol, liquid SD-E type and the like are added into the powder, but the addition of the forming agents not only leads the preparation process to be complicated, but also increases the probability of powder pollution; since the addition of alloying elements into the cermet is an effective method for improving the mechanical properties of the cermet, some researchers will add Cr, Ni, Mn and other powders on the basis of raw material powders, but the study on W-Fe-B ternary alloys without doping elements is lacked, and the further application in the industry is not facilitated. Therefore, in view of the wide prospect of the ternary boride, the invention explores a compression molding process without a forming agent and a method for preparing W-Fe-B hard alloy without doped elements.

Disclosure of Invention

The invention aims to provide a preparation method of W-Fe-B hard alloy, which solves the problems that the preparation process is complicated and the powder pollution probability is increased due to the addition of a forming agent in the conventional preparation method.

The technical scheme adopted by the invention is that the preparation method of the W-Fe-B hard alloy is implemented according to the following steps:

step 1, mixing the powders

Taking W powder, FeB powder and carbonyl Fe powder as raw materials, and uniformly mixing in a powder mixer to obtain mixed powder;

step 2, press forming

Putting the mixed powder obtained in the step 1 into a steel die to be pressed and molded to obtain a prefabricated blank;

step 3, sintering the green body

And (3) carrying out pressureless sintering on the prefabricated blank obtained in the step (2), and cooling to room temperature along with the furnace to obtain a complete W-Fe-B hard alloy blank.

The present invention is also characterized in that,

in the step 1, the mass ratio of W to FeB to Fe powder is 40-49: 25-35: 21-24, and mixing.

In the step 1, the particle size of W powder is 1-5 μm, the particle size of carbonyl Fe powder is 1-5 μm, and the particle size of FeB powder is 5-15 μm.

The mass ratio of the ball materials in the powder mixing machine is 1-2:1, the particle size of the grinding ball is 6mm, the frequency of the powder mixing machine is 50HZ, and the powder mixing time is 1-3 h.

The pressing pressure of the pressing forming in the step 2 is 300-500MPa, and the pressure maintaining time is 3-5 min.

The sintering temperature in the step 3 is 1000-.

The vacuum degree in the vacuum sintering furnace during vacuum sintering in the step 3 is 10^-2Pa, heating rate of 10 ℃ per minute.

The invention has the beneficial effects that:

the invention utilizes the reaction boronizing sintering principle, takes W powder, carbonyl Fe powder and FeB powder as raw materials, does not add other forming agents, has simple preparation process and does not increase powder pollution, prepares the W-Fe-B hard alloy by sintering in a vacuum pressureless method, and greatly improves the hardness of the alloy due to the W-Fe-B ternary hard phase in the alloy. Meanwhile, the invention provides an optimal process for preparing the hard alloy.

Drawings

FIG. 1 is a macroscopic view of a compact obtained in examples 1 to 4 of a method for producing a W-Fe-B cemented carbide according to the present invention;

FIG. 2 is a microstructure of a sample obtained in example 1 of a method for producing a W-Fe-B cemented carbide according to the present invention;

FIG. 3 is a microstructure of a sample obtained in example 2 of a method for producing a W-Fe-B cemented carbide according to the present invention;

FIG. 4 is a microstructure of a sample obtained in example 3 of a method for producing a W-Fe-B cemented carbide according to the present invention;

FIG. 5 shows the microstructure of a sample obtained in example 4 of the method for producing a W-Fe-B cemented carbide according to the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention relates to a preparation method of W-Fe-B hard alloy, which is implemented according to the following steps:

step 1, mixing the powders

Mixing W, FeB and Fe powder according to the mass ratio of 40-49: 25-35: 21-24, and uniformly mixing in a powder mixer to obtain mixed powder, wherein the particle size of W powder is 1-5 microns, the particle size of carbonyl Fe powder is 1-5 microns, the particle size of FeB powder is 5-15 microns, the mass ratio of balls in the powder mixer is 1-2:1, the particle size of grinding balls is 6mm, the frequency of the powder mixer is 50HZ, and the powder mixing time is 1-3 hours;

step 2, press forming

Putting the mixed powder obtained in the step 1 into a steel die, and performing compression molding to obtain a prefabricated blank, wherein the compression pressure is 300-500MPa, and the pressure maintaining time is 3-5 min;

step 3, sintering the green body

Carrying out pressureless vacuum sintering on the prefabricated blank obtained in the step 2, and setting the vacuum degree in a vacuum sintering furnace to be 10^-2Pa, controlling the heating rate at 10 ℃ per minute, raising the temperature in the furnace to 1000-1500 ℃, preserving the heat for 1-2 hours, carrying out liquid phase sintering, and finally cooling to room temperature along with the furnace to obtain a complete W-Fe-B hard alloy blank body, wherein the macro morphology of the W-Fe-B hard alloy blank body is shown in figure 1.

Example 1

The invention provides a preparation method of W-Fe-B hard alloy, which comprises the following steps:

step 1, mixing the powders

Respectively weighing 8.8g of W powder, 5.6g of carbonyl Fe powder and 4.2g of FeB powder, wherein the particle size of the W powder is 1 mu m, the particle size of the carbonyl Fe powder is 1um, and the particle size of the FeB powder is 10 um; then uniformly mixing the three kinds of powder on a powder mixer to obtain mixed powder; balls used for mixing powder are zirconia balls, the mass ratio of the balls to the materials is 1:1, the diameter of the balls is 6mm, the frequency of the powder mixing machine is 50HZ, and the total time is 2 hours;

step 2, press forming

Loading the mixed powder obtained in the step 2 in a steel die to be pressed into a blank under the pressure of 450MPa by using a jack, and keeping the pressure for 4 min;

step 3, sintering the green body

Sintering the obtained green body in a vacuum environment, firstly putting the green body into a vacuum sintering furnace, and setting the vacuum degree in the furnace to be 10^-2Pa, controlling the heating rate to be 10 ℃ per minute, raising the temperature in the furnace to 1000 ℃, preserving the heat for 1h, carrying out liquid phase sintering, and finally cooling along with the furnace until the preparation of the W-Fe-B hard alloy is finished. FIG. 2 shows the microstructure of the W-Fe-B cemented carbide of this example, wherein the bright white grain structure is W-Fe-B ternary boride hard phase, and the grey structure is W and Fe element binding phase wrapping the ternary boride. The ternary compound is unevenly distributed in the binder phase, and has small size and irregular shape. The hard alloy has HV of 105.97N/mm²The volumetric wear rate is 8.23X 10^-7·N^-3·m^-1。

Example 2

The invention provides a preparation method of W-Fe-B hard alloy, which comprises the following steps:

step 1, mixing the powders

Respectively weighing 8.8g of W powder, 5.6g of carbonyl Fe powder and 4.2g of FeB powder, wherein the particle size of the W powder is 1 mu m, the particle size of the carbonyl Fe powder is 1um, and the particle size of the FeB powder is 10 um; then uniformly mixing the three kinds of powder on a powder mixer to obtain mixed powder; grinding balls used for mixing powder are zirconia balls, the mass ratio of the balls to the materials is 1:1, the diameter of the balls is 6mm, the frequency of the powder mixing machine is 50HZ, and the total time is 2 hours;

step 2, press forming

Loading the mixed powder obtained in the step 2 in a steel die to be pressed into a blank under the pressure of 450MPa by using a jack, and keeping the pressure for 4 min;

step 3, sintering the green body

Sintering the obtained green body in a vacuum environment, firstly putting the green body into a vacuum sintering furnace, and setting the vacuum degree in the furnace to be 10^-2Pa, controlling the heating rate to be 10 ℃ per minute, raising the temperature in the furnace to 1300 ℃, preserving the heat for 1h, carrying out liquid phase sintering, and finally cooling along with the furnace until the preparation of the W-Fe-B hard alloy is finished. FIG. 3 shows the microstructure of the W-Fe-B cemented carbide of this example, with a reduced grey binder phase area compared to 1000 ℃. In addition, it can be seen in the micrograph that the white flaky W-Fe-B hard phase continues to grow in an agglomerated manner, and the amount becomes significantly larger. And there is a tendency for the hard phase interfaces to join together. The hard alloy has HV of 438.87N/mm²The volumetric wear rate is 5.23X 10^-7 _·N^-3 _·m^-1。

Example 3

The invention provides a preparation method of W-Fe-B hard alloy, which comprises the following steps:

step 1, mixing the powders

Respectively weighing 8.8g of W powder, 5.6g of carbonyl Fe powder and 4.2g of FeB powder, wherein the particle size of the W powder is 1 mu m, the particle size of the carbonyl Fe powder is 1um, and the particle size of the FeB powder is 10 um; then uniformly mixing the three kinds of powder on a powder mixer to obtain mixed powder; grinding balls used for mixing powder are zirconia balls, the mass ratio of the balls to the materials is 1:1, the diameter of the balls is 6mm, the frequency of the powder mixing machine is 50HZ, and the total time is 2 hours;

step 2, press forming

Loading the mixed powder obtained in the step 2 in a steel die to be pressed into a blank under the pressure of 450MPa by using a jack, and keeping the pressure for 4 min;

step 3, sintering the green body

Sintering the obtained green body in a vacuum environment, and firstly putting the green body inIn the vacuum sintering furnace, the vacuum degree in the furnace is set to be 10^-2Pa, controlling the heating rate to be 10 ℃ per minute, raising the temperature in the furnace to 1400 ℃, preserving the heat for 1h, carrying out liquid phase sintering, and finally cooling along with the furnace until the preparation of the W-Fe-B hard alloy is finished. As shown in FIG. 4, the microstructure of the W-Fe-B cemented carbide in the present example is clearly seen in comparison with the microstructure taken at 1300 ℃, wherein the white dendritic W-Fe-B ternary boride hard phase structure is formed, and the white long stripe is WFeB ternary boride hard phase, and the surrounding is also formed with liquid phase. Meanwhile, the W-Fe-B system alloy is in a molten state at 1400 ℃, so that the density of the WFeB cermet is obviously improved. The hard alloy has HV of 314.24N/mm²The volumetric wear rate is 5.63X 10^-7 _·N^-3 _·m^-1。

Example 4

The invention provides a preparation method of W-Fe-B hard alloy, which comprises the following steps:

step 1, mixing the powders

Respectively weighing 8.8g of W powder, 5.6g of carbonyl Fe powder and 4.2g of FeB powder, wherein the particle size of the W powder is 1 mu m, the particle size of the carbonyl Fe powder is 1um, and the particle size of the FeB powder is 10 um; then uniformly mixing the three kinds of powder on a powder mixer to obtain mixed powder; grinding balls used for mixing powder are zirconia balls, the mass ratio of the balls to the materials is 1:1, the diameter of the balls is 6mm, the frequency of the powder mixing machine is 50HZ, and the total time is 2 hours;

step 2, press forming

Loading the mixed powder obtained in the step 2 in a steel die to be pressed into a blank under the pressure of 450MPa by using a jack, and keeping the pressure for 4 min;

step 3, sintering the green body

Sintering the obtained green body in a vacuum environment, firstly putting the green body into a vacuum sintering furnace, and setting the vacuum degree in the furnace to be 10^-2Pa, controlling the heating rate to be 10 ℃ per minute, raising the temperature in the furnace to 1500 ℃, preserving the heat for 1h, carrying out liquid phase sintering, and finally cooling along with the furnace until the preparation of the W-Fe-B hard alloy is finished. FIG. 5 shows the microstructure of the W-Fe-B cemented carbide of this example, which is at 1400 deg.C and 1500 deg.CThe lower white flaky W-Fe-B ternary boride grows gradually in hardness, white oval spherical dendrites generated when the residual liquid phase is solidified still exist around the boride, and the hard phase is uniformly distributed in the bonding phase. The hard alloy has HV of 347.9N/mm²The volumetric wear rate is 5.02X 10^-7 _·N^-3 _·m^-1。

The following table shows the results of performance testing of samples prepared in four examples of the invention: