An atomization device and production method for suppressing the formation of nickel-based superalloy satellite powder

Abstract

The present invention relates to the fields of powder metallurgy and 3D printing technologies, and particularly to an atomization device and a production method for suppressing the formation of satellite powder of nickel-based superalloys, including an atomizer and an atomization chamber. The atomizer includes Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3, an annular-hole type air supplementing device, and an annular-gap type exhaust device. Physical Obstruction 1 is arranged around the effective atomization area of the atomization chamber. The annular-hole type air supplementing device is arranged at the lower part of Physical Obstruction 1. Physical Obstruction 2, Physical Obstruction 3, and the annular-gap type exhaust device are arranged at the bottom of the annular-hole type air supplementing device. By adopting the method for suppressing the formation of satellite powder of nickel-based superalloys, the gas flow field distribution in the atomization furnace can be significantly improved, the effective collision between powder particles / droplets can be reduced, and the probability of particles flowing back to the top of the atomization chamber can be decreased.

Description

Technical Field

[0001] The present invention relates to the technical fields of powder metallurgy and 3D printing, and particularly relates to an atomization device and a production method for suppressing the formation of satellite powder of nickel-based superalloy powder. Background Art

[0002] Superalloy powder is an important raw material for advanced powder metallurgy technology and 3D printing technology. At present, the main methods for preparing superalloy powder are Plasma Rotating Electrode Process (PREP) and Argon Atomization (AA). Compared with the PREP method, the powder prepared by the AA method has the advantages of high fine powder yield, low cost, small average particle size, and uniform microstructure. However, there are also defects in powder morphology such as many satellite powders and poor sphericity. Satellite powder generally refers to a powder structure in which small-sized powders adhere to the surface of large-sized powders to form a satellite shape. Satellite powder will reduce the sphericity, fluidity, and loose packing density of the powder, etc., and is a common defect in gas atomization powder making.

[0003] Powder morphology has a significant impact on powder fluidity, loose packing density, and tapped density, and ultimately affects the tissue uniformity and performance stability of the workpiece. With the continuous improvement of the reliability of aero-engines, the requirements for the tissue uniformity and performance stability of superalloy turbine disks are getting higher and higher, thus putting more stringent requirements on powder morphology, loose packing density, and tapped density. The rapidly developing 3D printing technology has more strict requirements on the powder morphology and fluidity for 3D printing.

[0004] High-sphericity powder has a series of advantages such as good fluidity, high loose packing density, and high tapped density, and thus has been more and more widely used in advanced manufacturing fields such as 3D printing. Especially for forming technologies such as selective laser melting that have higher requirements for powder morphology, high-sphericity powder has more obvious advantages. Therefore, improving the morphology of argon atomized superalloy powder plays an important role in enhancing the powder flow and packing characteristics.

[0005] Existing devices mainly use physical shielding methods to block the powder particle / droplet backflow, and suppress the formation of satellite powder by reducing the powder particle / droplet backflow to the atomization cone. However, this type of device cannot completely block the powder particles / droplets, and there will still be some particles / droplets bypassing the bottom of the shield and flowing back to the atomization cone, resulting in the collision and adhesion of the particles / droplets and the droplets in the atomization cone, and the prepared powder still contains a certain proportion of satellite powder. Summary of the Invention

[0006] The first aspect of the present invention provides an atomization device for suppressing the formation of nickel-based superalloy satellite powder, including an atomizer and an atomization chamber. The atomizer includes Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3, an annular hole type air supplement device, and an annular slit type exhaust device. Physical Obstruction 1 is arranged around the effective atomization area of the atomizer. The annular hole type air supplement device is arranged below Physical Obstruction 1. Physical Obstruction 2, Physical Obstruction 3, and the annular slit type exhaust device are arranged at the bottom of the annular hole type air supplement device.

[0007] Using the above atomization device can effectively reduce the reflux of powder particles / droplets in the furnace to the top of the atomization chamber, effectively reduce the collision between particles / droplets, and provide a technical reference for the preparation of metal powder with high sphericity and high fluidity.

[0008] In some embodiments, the inner diameter of the intake pipe of the annular hole type air supplement device is 20 mm to 25 mm, the number of annular holes is 16 or 32, and the diameter of the annular holes is 2 mm to 5 mm.

[0009] The inner diameter, the number of annular holes, and the diameter of the annular holes of the annular hole type air supplement device have a significant impact on the gas flow rate by affecting the pipe cross-sectional area and the average flow velocity, and then have a significant impact on the reflux of powder particles / droplets, and ultimately have an important impact on the sphericity of the nickel-based superalloy. On the one hand, under a certain air supplement pressure, if the inner diameter of the annular hole type air supplement device is too large, the number of annular holes is more, and the diameter of the annular holes is larger, it will lead to a lower gas velocity of the air supplement, and the downward gas flow rate cannot offset the upward reflux rate of the powder particles / droplets, and a slightly positive pressure state cannot be formed here, so the reflux of the powder particles / droplets cannot be effectively suppressed. On the other hand, if the inner diameter is too small, the number of annular holes is less, and the diameter of the annular holes is smaller, it will lead to a lower pipe cross-sectional area of the air supplement, and the lower gas flow rate cannot prevent the reflux of some powder particles / droplets, and a slightly positive pressure state cannot be formed here. In both cases, the sphericity of the nickel-based superalloy will be lower.

[0010] In some embodiments, the inner diameter of the outlet pipe of the annular slit type exhaust device is 40 mm to 45 mm, the width of the annular slit is 5 mm to 10 mm, and the angle between the annular slit and the horizontal plane is 45° to 50°.

[0011] The inner diameter, annular gap width, and angle between the annular gap and the horizontal plane of the outlet pipe of the annular gap type exhaust device also have a significant impact on the discharge effect of powder particles / droplets, and thus have a significant impact on the quality of nickel-based high-temperature alloys. On the one hand, if the inner diameter of the outlet pipe of the annular gap type exhaust device is too large, the wider the annular gap width, and the larger the angle between the annular gap and the horizontal plane, the smaller the discharge speed of the discharge pipe for the refluxed powder particles / droplets, which will lead to poor discharge effect for the refluxed powder particles / droplets, and some particles / droplets will bypass the bottom of the exhaust device and continue to flow back to the top of the atomization chamber; on the other hand, if the inner diameter is too small, the narrower the annular gap width, and the smaller the angle between the annular gap and the horizontal plane, the smaller the cross-sectional area of the discharge pipe will be, resulting in a large number of particles / droplets not being discharged in time, both of which will lead to a decrease in the sphericity of the powder.

[0012] In some embodiments, the thickness of the physical shield 1, the physical shield 2 and the physical shield 3 are all 2 mm to 5 mm.

[0013] In some implementations, the physical shielding 3 is an arc-shaped shielding structure.

[0014] In some embodiments, the material of the physical shield 1, physical shield 2, physical shield 3, annular hole type air supply device, and annular gap type exhaust device includes at least one of stainless steel, aluminum alloy, copper alloy, nickel-based high-temperature alloy, and titanium alloy.

[0015] Furthermore, the materials of the physical shield 1, the physical shield 2, the physical shield 3, the annular hole type air supply device, and the annular gap type exhaust device are all made of stainless steel.

[0016] Working principle: The device is divided into two parts. The first part is the physical shielding 3 and the annular gap type exhaust device. Its main function is that when the refluxed powder particles / droplets return to the bottom of the physical shielding 3, the particle / droplet flow will move along the arc at the bottom of the physical shielding 3 to the position of the annular gap type exhaust device, and finally the particles / droplets flow through the annular gap and are discharged outside the atomization chamber; the second part is the physical shielding 1, the physical shielding 2 and the annular hole type air supply device. Its main function is that when the particle / droplet flow that has not been completely discharged reaches the bottom of the annular hole type air supply device, due to the existence of air supply, the place is in a slightly positive pressure state, which inhibits the particle / droplet flow that has not been discharged by the exhaust device from continuing to flow back to the top of the atomization chamber, and prevents the refluxed particles / droplets from colliding with the droplets in the atomization cone, so as to achieve the purpose of improving the sphericity of the powder.

[0017] The second aspect of the present invention provides a production method for inhibiting the formation of satellite powder of nickel-based high-temperature alloys, comprising: the high-temperature alloy melt flows into an atomization chamber through a guide tube, is broken up by high-pressure atomizing gas, and simultaneously an annular gap type air supply device and an annular hole type exhaust device in the atomizer are opened to obtain high-temperature alloy powder.

[0018] In some embodiments, the atomization pressure of the high-pressure atomizing gas is 2.5 to 3.5 MPa.

[0019] In some embodiments, the air supplement pressure of the annular gap type air supplement device is 0.4 to 0.8 MPa, and the exhaust pressure of the annular hole type exhaust device is 0.5 to 0.6 MPa.

[0020] In some embodiments, the gas temperatures at the inlets of the annular gap type air supplement device and the outlets of the annular hole type exhaust device are both ambient temperatures.

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

[0022] By adopting the method for suppressing the formation of satellite powder of nickel-based superalloy, the gas flow field distribution in the atomization furnace can be significantly improved, the effective collision between powder particles / droplets can be reduced, and the probability of particles flowing back to the top of the atomization chamber can be decreased. Thus, nickel-based superalloy powder with less satellite powder content can be obtained, the fluidity and powder spreading uniformity of the powder can be significantly improved, and it helps the rapid development of nickel-based superalloy powder for advanced powder metallurgy technology and 3D printing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of the atomization device of the present invention.

[0024] Figure 2 It is a structural diagram of the atomizer of the present invention.

[0025] Figure 3 In it, a is the superalloy powder prepared in Comparative Example 1, and b is the morphology diagram of the superalloy powder prepared in Example 2.

[0026] Figure 4 In it, a is the aspect ratio distribution diagram of the superalloy powder prepared in Comparative Example 1 and Example 2, b is the sphericity distribution diagram of the superalloy powder prepared in Comparative Example 1 and Example 2, and c is the outgrowth index diagram of the superalloy powder prepared in Comparative Example 1 and Example 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0028] Example 1

[0029] An atomization device for suppressing the formation of satellite powder of nickel-based superalloy, see Figure 1-2, including an atomizer and an atomization chamber. The atomizer includes Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3, an annular hole type air supplement device, and an annular slit type exhaust device; Physical Obstruction 1 is arranged around the effective atomization area of the atomizer, the annular hole type air supplement device is arranged at the lower part of Physical Obstruction 1, Physical Obstruction 2 is arranged at the bottom of the annular hole type air supplement device, and Physical Obstruction 3 and the annular slit type exhaust device.

[0030] The inner diameter of the intake pipe of the annular hole type air supplement device is 25 mm, the number of annular holes is 32, and the diameter of the annular holes is 5 mm.

[0031] The inner diameter of the outlet pipe of the annular slit type exhaust device is 40 mm, the width of the annular slit is 5 mm, and the angle between the annular slit and the horizontal plane is 45°.

[0032] The thicknesses of Physical Obstruction 1, Physical Obstruction 2, and Physical Obstruction 3 are all 2 mm.

[0033] Physical Obstruction 3 is an arc-shaped shielding structure.

[0034] The materials of Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3, the annular hole type air supplement device, and the annular slit type exhaust device are all stainless steel.

[0035] Example 2

[0036] A production method for suppressing the formation of satellite powder of nickel-based superalloy includes: the superalloy melt flows into the atomization chamber in Example 1 through a diversion pipe, is broken by high-pressure atomizing gas, and at the same time, the annular slit type air supplement device and the annular hole type exhaust device in the atomizer in Example 1 are opened to obtain superalloy powder.

[0037] The atomization pressure of the high-pressure atomizing gas is 2.5 MPa.

[0038] The air supplement pressure of the annular slit type air supplement device is 0.6 MPa, and the exhaust pressure of the annular hole type exhaust device is 0.5 MPa.

[0039] The gas temperatures at the inlet of the annular slit type air supplement device and the outlet of the annular hole type exhaust device are both ambient temperatures.

[0040] Comparative Example 1

[0041] A production method for suppressing the formation of satellite powder of nickel-based superalloy, the specific implementation method is the same as that in Example 2, the difference is that the superalloy melt flows into the atomization chamber in Example 1 through a diversion pipe, is broken by high-pressure atomizing gas to obtain superalloy powder, and does not pass through the atomizer in Example 1.

[0042] Performance Test

[0043] (1) Morphology SEM Characterization

[0044] The morphology of the high temperature alloy powder prepared in Comparative Example 1 is as follows Figure 3 As shown on the left side of a, the powder morphology is poor, there are a lot of satellite powders and coated powders in the powder, and even a lot of powder agglomeration occurs; the high temperature alloy powder morphology prepared in Example 2 is as follows Figure 3 As shown in b on the right side, the powder morphology has been significantly improved, the agglomeration phenomenon in the powder has been greatly reduced, the number of satellite powders and coated powders has been greatly reduced, and the powder shape has become more regular.

[0045] (2) Quantitative characterization of morphology

[0046] like Figure 4 As shown, the left lines in a and b and the square in c are the high-temperature alloy powder prepared in Comparative Example 1, and the right lines in a and b and the circle in c are the morphology of the high-temperature alloy powder prepared in Example 2. The aspect ratio (AR), sphericity (SPHT) and outgrowth index (Outgrowth) of the powder prepared in Example 2 and Comparative Example 1 are clearly distinguished. The average value of AR is increased from 0.762 to 0.851, the average value of SPHT is increased from 0.796 to 0.884, and the proportion of satellite powder (Outgrowth>0%) is reduced by 28%. The quantitative characterization results of Outgrowth show that there are a large number of satellite powders in the powder of Comparative Example 1, and the proportion of satellite powder adhering to two particles is 46%, while the proportion of spherical powder without adhering particles is only about 21%. In Example 2, the proportion of satellite powder adhering to two particles is reduced to 25%, while the proportion of spherical powder without adhering particles is increased to 49% (Table 1). This shows that the atomizer significantly improves the powder morphology, with powder AR increasing by 11.7%, SPHT increasing by 11.1%, and the proportion of satellite powder (Outgrowth>0%) decreasing by 28%, effectively verifying the optimization control effect of powder morphology, indicating that the powder morphology after optimization is significantly optimized and the number of satellite powder is significantly reduced.

[0047] Table 1 Shape descriptors of powders prepared before and after optimization

[0048]

[0049]

[0050] (3) Quantitative characterization of powder flow and stacking properties

[0051] As shown in Table 2, the powder morphology has a significant impact on the flow and packing characteristics of the powder. When the powder AR increases from 0.762 to 0.851, SPHT increases from 0.796 to 0.884, and Outgrowth = 0% increases from 21% to 49%, the powder changes from initially non-flowable to flowable, with a flowability of 18.27 s / 50 g. The angle of repose of the powder decreases from 35° to 30.2°, and the angle of collapse decreases from 26.3° to 24.6°. The change in the angle of repose is more obvious. The bulk density of the powder is tested, and it is found that as the powder morphology is gradually optimized and the satellite powder continuously decreases, the loose bulk density of the powder continuously increases, from 3.76 g / cm 3 increases to 4.49 g / cm 3 .

[0052] Through actual atomization experiment verification and quantitative characterization of the powder morphology, it is fully proved that the powder morphology has been significantly optimized, and the optimized powder morphology is beneficial to the improvement of the powder flow and packing characteristics.

[0053] Quantitative characterization of the flow and packing characteristics of the powder prepared before and after optimization in Table 2

[0054]

[0055] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An atomization device for suppressing the formation of nickel-based superalloy satellite powder, comprising an atomizer and an atomization chamber, characterized in that, The atomizer includes Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3, an annular hole type air supplementing device, and an annular slit type exhaust device; Physical Obstruction 1 is arranged around the effective atomization area of the atomizer, the annular hole type air supplementing device is arranged below Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3 and the annular slit type exhaust device are sequentially arranged at the bottom of the annular hole type air supplementing device, and the annular slit type exhaust device is arranged at the bottom of Physical Obstruction 3; The inner diameter of the air inlet pipe of the annular hole type air supplementing device is 20 mm to 25 mm, the number of annular holes is 16 or 32, and the diameter of the annular holes is 2 mm to 5 mm; The inner diameter of the air outlet pipe of the annular slit type exhaust device is 40 mm to 45 mm, the width of the annular slit is 5 mm to 10 mm, and the included angle between the annular slit and the horizontal plane is 45° to 50°; The thicknesses of Physical Obstruction 1, Physical Obstruction 2 and Physical Obstruction 3 are all 2 mm to 5 mm; Physical Obstruction 3 is an arc-shaped shielding structure, the radius of the arc is 230 to 240 mm, and the arc angle is 130 to 140°; 2. The atomization device for suppressing the formation of nickel-based superalloy satellite powder according to claim 1, wherein The materials of Physical Obstruction 1, Physical Obstruction 2, Physical Obstruction 3, the annular hole type air supplementing device, and the annular slit type exhaust device all include at least one of stainless steel, aluminum alloy, copper alloy, nickel-based superalloy, and titanium alloy; 3. A production method for suppressing the formation of nickel-based superalloy satellite powder, characterized in that, Using the atomization device for suppressing the formation of nickel-based superalloy satellite powder according to claim 1 or 2, comprising: a superalloy melt flows into the atomization chamber through a diversion tube, is broken by high-pressure atomizing gas, and at the same time, the annular hole type air supplementing device and the annular slit type exhaust device in the atomizer are opened to obtain superalloy powder.

4. The production method for suppressing the formation of nickel-based superalloy satellite powder according to claim 3, characterized in that, The atomization pressure of the high-pressure atomizing gas is 2.5 to 3.5 MPa; 5. The production method for suppressing the formation of nickel-based superalloy satellite powder according to claim 4, characterized in that, The air supplementing pressure of the annular hole type air supplementing device is 0.4 to 0.8 MPa, and the exhaust pressure of the annular slit type exhaust device is 0.5 to 0.6 MPa; 6. The production method for suppressing the formation of nickel-based superalloy satellite powder according to claim 5, characterized in that, The gas temperatures at the inlet of the annular hole type air supplementing device and the outlet of the annular slit type exhaust device are both ambient temperature.

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