Preparation method of high-temperature alloy blank embedded with cooling liquid

Abstract

The invention relates to a preparation method of a high-temperature alloy blank embedded with cooling liquid, which comprises the following steps of: forming a cylindrical high-temperature alloy block with nickel-based high-temperature alloy powder on the periphery by a cooling core consisting of Ti powder, Al powder, Mg powder and Zn powder through a sheath structure, and opening an air exhaust hole of a sheath; then the high-temperature alloy block is pressed in a stepped heating mode, so that an internal heat conduction and heat dissipation carrier structure is constructed, firstly, the Ti powder and the Al powder are pressed at the temperature of 700 DEG C, then the Ti powder and the Al powder are pressed at the temperature of 1070 DEG C, the Ti powder and the Al powder are subjected to plastic deformation, the Mg powder is in a softened state and is dispersed and distributed in the tissue, and high-temperature alloy powder particles are recrystallized; and after pressing is conducted at the temperature of 1200 DEG C, the Ti powder and the Al powder are subjected to a thermal explosion reaction, the organization structure becomes disordered, the Mg powder is in a softened state and is dispersed and distributed in the organization, high-temperature alloy powder particles are completely recrystallized, and the compactness reaches 100%.

Description

Technical Field

[0001] The invention discloses a method for preparing a high-temperature alloy blank embedded with a coolant, and belongs to the technical field of processing and manufacturing heat dissipation components. Background Art

[0002] Large cylindrical forgings are widely used in nuclear power, hydropower, petrochemicals, coal liquefaction, gasification and other fields. The traditional high-temperature forging process using solid billets is complicated, with disadvantages such as low billet utilization and long production cycle. In addition, the use of large-section billets reduces the cooling rate and causes serious macrosegregation.

[0003] Compared with the production of cylindrical forgings with solid billets, the use of hollow billets has the following advantages: it can save punching and other processes, simplify forging operations, and shorten the process flow; it can significantly improve the utilization rate of billets and save materials; the processing cross-section is greatly reduced, and simultaneous internal and external cooling increases the cooling rate, which can reduce segregation and improve material homogeneity; it can improve the processing capacity of existing equipment and produce larger tonnage cylindrical forgings.

[0004] At present, the domestic hollow billet preparation technology is basically mature, but unlike solid billets, the hollow billets cannot be improved through repeated upsetting and drawing to improve their structure. The forging process is irreversible, and new technical specifications need to be established to control the shape and properties. Summary of the invention

[0005] The present invention is designed to address the above-mentioned prior art conditions and provides a method for preparing a high-temperature alloy billet with embedded coolant, the purpose of which is to achieve the overall forming of a hollow high-temperature alloy billet with a cooling medium and to reduce the structural weight of the billet as much as possible.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] The preparation method of the high-temperature alloy blank with embedded coolant is as follows: a cooling core composed of Ti powder, Al powder, Mg powder and Zn powder is formed into a cylindrical high-temperature alloy block with a nickel-based high-temperature alloy powder on the outer periphery through a sheath structure, and the exhaust hole of the sheath is opened; then the high-temperature alloy block is placed in a vacuum induction heating furnace and heated to 900°C, and maintained for 0.5-1h, at which time the vaporized Zn is extracted from the exhaust hole, and after the cylinder is cooled, the exhaust hole is blocked; the high-temperature alloy block is placed in a mold and heated to 700°C together with the mold, and then kept warm for 1h. , the high-temperature alloy block is forged and pressed at a pressure of 1000-1200MPa, and the pressure is maintained for 10s; heating is continued, and when the temperature reaches 1070°C, the high-temperature alloy block is kept warm for 1h, and the high-temperature alloy block is continued to be forged and pressed at a pressure of 1300-1500MPa, and the pressure is maintained for 10s; heating is continued, and when the temperature reaches 1200°C, the high-temperature alloy block is kept warm for 1h, and the high-temperature alloy block is continued to be forged and pressed at a pressure of 1600-1800MPa, and the pressure is maintained for 10s; heating is stopped, and a high-temperature alloy billet with embedded coolant is obtained after natural cooling.

[0008] During implementation, the particle size of the Ti powder and the Al powder is -200 to -300 mesh, and the particle size of the Mg powder and the Zn powder is -350 to -400 mesh.

[0009] During implementation, the volume proportions of the Ti powder, Al powder, Mg powder and Zn powder are 20%, 20%, 30% and 30% respectively.

[0010] In practice, the preparation process of the cooling core is to mechanically mix Ti powder, Al powder, Mg powder and Zn powder in a vacuum environment, and then cold isostatically press them into a columnar cooling core, with a cold isostatic pressing pressure of 1000-1400 MPa and a holding time of 2-3 hours.

[0011] During implementation, the density of the cooling core is 80-90%, large particles of Ti powder and Al powder are distributed in the cooling core, and plastic deformation occurs, and Mg powder and Zn powder with smaller powder particle size are dispersed in the microstructure composed of Ti powder and Al powder.

[0012] When implemented, the steps of the preparation method are as follows:

[0013] Step 1: Raw material preparation

[0014] Prepare Ti powder, Al powder, Mg powder and Zn powder, the powder size of Ti powder and Al powder is -200 to -300 mesh, and the powder size of Mg powder and Zn powder is -350 to -400 mesh;

[0015] Step 2: Cooling core preparation

[0016] Ti powder, Al powder, Mg powder and Zn powder with volume proportions of 20%, 20%, 30% and 30% respectively are mechanically mixed in a vacuum environment, and then cold isostatically pressed into a cylindrical cooling core. The cold isostatic pressing pressure is 1000-1400MPa, and the holding time is 2-3h. The density of the cooling core is about 80-90%. Large particles of Ti powder and Al powder are distributed in the cooling core, and plastic deformation occurs. Mg powder and Zn powder with smaller powder size are dispersed in the microstructure composed of Ti powder and Al powder.

[0017] Step 3: Cooling core drying

[0018] Mix Ti powder and Al powder with volume proportions of 50% and 50% respectively and dry them in a drying oven at a temperature of 100-200°C for 3-5 hours. Then use an alcohol spray gun to spray the dried Ti powder and Al powder on the outer surface of the cooling core. When the sprayed material covers the outer surface, put the cooling core into a drying oven for drying at a temperature of 100-200°C for 3-5 hours.

[0019] Step 4: Prepare high temperature alloy block

[0020] A cylindrical sheath is prepared with a 304 stainless steel tube. After the upper and lower parts are sealed and welded, an exhaust hole is left in the center of the upper steel plate. A cooling core is placed in the sheath. The cooling core is located at the geometric center of the sheath. The inner size of the sheath is 30-50% larger than the outer size of the cooling core. The cooling core is surrounded by a nickel-based powder high-temperature alloy. At this time, the exhaust hole is not blocked to obtain a high-temperature alloy block.

[0021] Step 5: Solidification of high temperature alloy block

[0022] Then the high temperature alloy block is placed in a vacuum induction heating furnace and heated to 900°C for 0.5-1h, at which time the vaporized Zn is extracted from the exhaust hole. After the cylinder is cooled, the exhaust hole is sealed.

[0023] Put the high-temperature alloy block into the mold and heat it to 700°C together with the mold. After keeping the temperature for 1 hour, forge and press the high-temperature alloy block at a pressure of 1000-1200MPa for 10 seconds.

[0024] Continue heating, and when the temperature reaches 1070°C, keep it warm for 1 hour, and then continue forging and pressing the high-temperature alloy block at a pressure of 1300-1500MPa for 10 seconds;

[0025] Continue heating, and when the temperature reaches 1200°C, keep it warm for 1 hour, and then continue forging and pressing the high-temperature alloy block at a pressure of 1600-1800 MPa for 10 seconds;

[0026] The heating is stopped and the high-temperature alloy billet with embedded coolant is obtained after natural cooling.

[0027] The characteristics and beneficial effects of the technical solution of the present invention are as follows:

[0028] 1. Through the scheme of the present invention, a high-temperature alloy billet with embedded coolant is prepared. When the billet works at room temperature to 700°C, the internal Mg particles / lamellae / strips can accelerate heat conduction and heat dissipation. When the ambient temperature reaches 800-900°C, the internal Mg particles / lamellae / strips soften, the fluidity is enhanced, and they adhere to the network left by the thermal explosion reaction of Ti and Al, which indirectly accelerates heat conduction and heat dissipation.

[0029] 2. In the scheme of the present invention, the high-temperature alloy block realizes the construction of the internal heat-conducting and heat-dissipating carrier structure by step-by-step temperature pressing. First, at 700°C pressing, Ti powder and Al powder continue to undergo plastic deformation, filling up some of the holes where Zn leaves, and the powder high-temperature alloy powder particles also undergo plastic deformation and recovery. Secondly, at 1070°C pressing, Ti powder and Al powder continue to undergo plastic deformation, Mg powder is in a softened state and dispersed in the organization. Under the action of gravity, it is partially accumulated at the bottom of the organization, and the powder high-temperature alloy powder particles undergo recrystallization, the holes are closed, and the density is improved. At 1200°C pressing, Ti powder and Al powder undergo thermal explosion reaction, the organizational structure becomes chaotic, Mg powder is in a softened state and dispersed in the organization, the powder high-temperature alloy powder particles are completely recrystallized, and the density reaches 100%;

[0030] 3. In the scheme of the present invention, the use temperature of the obtained powder high-temperature alloy block blank with embedded coolant can be increased to 900°C through the construction of the cooling core and the step-by-step temperature pressing of the powder direct forging, and the structure of the powder high-temperature alloy block sheath can be flexibly adjusted according to the structural shape of the final part. In actual use, when the powder high-temperature alloy is radiated by heat and then conducted to the inside, the network structure of the internal Ti and Al components has higher thermal conductivity and heat capacity, so that the heat on the surface of the powder high-temperature alloy is quickly transferred to the inside. At this time, Mg begins to soften due to the influence of heat. In this process, Mg relies on good heat dissipation to transfer heat to the network structure of Ti and Al components and the surface of the powder high-temperature alloy, and conducts heat with the environment, thereby forming a heat dissipation cycle;

[0031] Fourth, in the scheme of the present invention, the Zn powder in the cooling core acts as a temporary structure and is discharged by gasification before pressing, thus providing a buffer space for the subsequent thermal explosion reaction of the pressing machine;

[0032] 5. In the scheme of the present invention, the Ti powder and Al powder layer sprayed on the periphery of the cooling core acts as a buffer layer during the pressing process, preventing the higher-strength powder high-temperature alloy powder from excessively impacting the cooling core structure during the pressing process. In addition, the Ti powder and Al powder layer sprayed on the periphery of the cooling core, during the pressing process at 1070°C, locally thermally exploded in advance due to the deformation temperature rise of the powder high-temperature alloy, forming a circle of elastic layer.

[0033] 6. The high-temperature alloy blank with embedded coolant prepared by the solution of the present invention can be widely used in non-rotating components such as engine casings and shafts. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be further described in detail below in conjunction with embodiments:

[0035] In this embodiment, the steps of preparing the high temperature alloy blank with embedded coolant of the present invention are as follows:

[0036] Step 1: Raw material preparation

[0037] Prepare Ti powder, Al powder, Mg powder and Zn powder, the powder size of Ti powder and Al powder is -200 to -300 mesh, and the powder size of Mg powder and Zn powder is -350 to -400 mesh;

[0038] Step 2: Cooling core preparation

[0039] Ti powder, Al powder, Mg powder and Zn powder with volume proportions of 20%, 20%, 30% and 30% respectively are mechanically mixed in a vacuum environment, and then cold isostatically pressed into a cylindrical cooling core. The cold isostatic pressing pressure is 1000-1400MPa, and the holding time is 2-3h. The density of the cooling core is about 80-90%. Large particles of Ti powder and Al powder are distributed in the cooling core, and plastic deformation occurs. Mg powder and Zn powder with smaller powder size are dispersed in the microstructure composed of Ti powder and Al powder.

[0040] Step 3: Cooling core drying

[0041] Mix Ti powder and Al powder with volume proportions of 50% and 50% respectively and dry them in a drying oven at a temperature of 100-200°C for 3-5 hours. Then use an alcohol spray gun to spray the dried Ti powder and Al powder on the outer surface of the cooling core. When the sprayed material covers the outer surface, put the cooling core into a drying oven for drying at a temperature of 100-200°C for 3-5 hours.

[0042] Step 4: Prepare high temperature alloy block

[0043] A cylindrical sheath is prepared with a 304 stainless steel tube. After the upper and lower parts are sealed and welded, an exhaust hole is left in the center of the upper steel plate. A cooling core is placed in the sheath. The cooling core is located at the geometric center of the sheath. The inner size of the sheath is 30-50% larger than the outer size of the cooling core. The cooling core is surrounded by a nickel-based powder high-temperature alloy. At this time, the exhaust hole is not blocked to obtain a high-temperature alloy block.

[0044] Step 5: Solidification of high temperature alloy block

[0045] Then the high temperature alloy block is placed in a vacuum induction heating furnace and heated to 900°C for 0.5-1h, at which time the vaporized Zn is extracted from the exhaust hole. After the cylinder is cooled, the exhaust hole is sealed.

[0046] Put the high-temperature alloy block into the mold and heat it to 700°C together with the mold. After keeping the temperature for 1 hour, forge and press the high-temperature alloy block at a pressure of 1000-1200MPa for 10 seconds.

[0047] Continue heating, and when the temperature reaches 1070°C, keep it warm for 1 hour, and then continue forging and pressing the high-temperature alloy block at a pressure of 1300-1500MPa for 10 seconds;

[0048] Continue heating, and when the temperature reaches 1200°C, keep it warm for 1 hour, and then continue forging and pressing the high-temperature alloy block at a pressure of 1600-1800 MPa for 10 seconds;

[0049] The heating is stopped and the high-temperature alloy billet with embedded coolant is obtained after natural cooling.

Claims

1. A method for preparing a high-temperature alloy blank with an embedded coolant, characterized in that: The preparation method comprises the following steps: a cooling core composed of Ti powder, Al powder, Mg powder and Zn powder is formed into a cylindrical high-temperature alloy block with a nickel-based high-temperature alloy powder on the outer periphery through a jacket structure, and the exhaust hole of the jacket is opened; the high-temperature alloy block is then placed in a vacuum induction heating furnace and heated to 900°C for 0.5-1h, at which time the vaporized Zn is extracted from the exhaust hole, and after the cylinder is cooled, the exhaust hole is blocked; the high-temperature alloy block is placed in a mold and heated to 700°C together with the mold, and after keeping the temperature for 1h, the high-temperature alloy block is heated to 700°C. The forging and pressing is performed at a pressure of 1000-1200MPa and the pressure is maintained for 10s; the heating is continued, and when the temperature reaches 1070°C, the high-temperature alloy block is kept warm for 1h, and the forging and pressing is continued at a pressure of 1300-1500MPa and the pressure is maintained for 10s; the heating is continued, and when the temperature reaches 1200°C, the high-temperature alloy block is kept warm for 1h, and the forging and pressing is continued at a pressure of 1600-1800MPa and the pressure is maintained for 10s; the heating is stopped, and the high-temperature alloy billet with embedded coolant is obtained after natural cooling.

2. The method for preparing a high-temperature alloy blank with embedded coolant according to claim 1, characterized in that: The powder particle size of the Ti powder and the Al powder is -200 to -300 mesh, and the powder particle size of the Mg powder and the Zn powder is -350 to -400 mesh.

3. The method for preparing a high temperature alloy blank with embedded coolant according to claim 1, characterized in that: The volume proportions of the Ti powder, Al powder, Mg powder and Zn powder are 20%, 20%, 30% and 30% respectively.

4. The method for preparing a high-temperature alloy blank with embedded coolant according to claim 1, characterized in that: The preparation process of the cooling core is to mechanically mix Ti powder, Al powder, Mg powder and Zn powder in a vacuum environment, and then cold isostatically press them into a columnar cooling core, the cold isostatic pressing pressure is 1000-1400MPa, and the pressure holding time is 2-3h.

5. The method for preparing a high temperature alloy blank with embedded coolant according to claim 1 or 4, characterized in that: The cooling core has a density of 80-90%, large particles of Ti powder and Al powder are distributed in the cooling core, and plastic deformation occurs, and Mg powder and Zn powder with smaller powder particle size are dispersed in the microstructure composed of Ti powder and Al powder.

6. The method for preparing a high temperature alloy blank with embedded coolant according to claim 1, characterized in that: The steps of the preparation method are as follows: Step 1: Raw material preparation Prepare Ti powder, Al powder, Mg powder and Zn powder, the powder size of Ti powder and Al powder is -200 to -300 mesh, and the powder size of Mg powder and Zn powder is -350 to -400 mesh; Step 2: Cooling core preparation Ti powder, Al powder, Mg powder and Zn powder with volume proportions of 20%, 20%, 30% and 30% respectively are mechanically mixed in a vacuum environment, and then cold isostatically pressed into a cylindrical cooling core. The cold isostatic pressing pressure is 1000-1400MPa, and the holding time is 2-3h. The density of the cooling core is about 80-90%. Large particles of Ti powder and Al powder are distributed in the cooling core, and plastic deformation occurs. Mg powder and Zn powder with smaller powder size are dispersed in the microstructure composed of Ti powder and Al powder. Step 3: Cooling core drying Mix Ti powder and Al powder with volume proportions of 50% and 50% respectively and dry them in a drying oven at a temperature of 100-200°C for 3-5 hours. Then use an alcohol spray gun to spray the dried Ti powder and Al powder on the outer surface of the cooling core. When the sprayed material covers the outer surface, put the cooling core into a drying oven for drying at a temperature of 100-200°C for 3-5 hours. Step 4: Prepare high temperature alloy block A cylindrical sheath is prepared with a 304 stainless steel tube. After the upper and lower parts are sealed and welded, an exhaust hole is left in the center of the upper steel plate. A cooling core is placed in the sheath. The cooling core is located at the geometric center of the sheath. The inner size of the sheath is 30-50% larger than the outer size of the cooling core. The cooling core is surrounded by a nickel-based powder high-temperature alloy. At this time, the exhaust hole is not blocked to obtain a high-temperature alloy block. Step 5: Solidification of high temperature alloy block Then the high temperature alloy block is placed in a vacuum induction heating furnace and heated to 900°C for 0.5-1h, at which time the vaporized Zn is extracted from the exhaust hole. After the cylinder is cooled, the exhaust hole is sealed. Put the high-temperature alloy block into the mold and heat it to 700°C together with the mold. After keeping the temperature for 1 hour, forge and press the high-temperature alloy block at a pressure of 1000-1200MPa for 10 seconds. Continue heating, and when the temperature reaches 1070°C, keep it warm for 1 hour, and then continue forging and pressing the high-temperature alloy block at a pressure of 1300-1500MPa for 10 seconds; Continue heating, and when the temperature reaches 1200°C, keep it warm for 1 hour, and then continue forging and pressing the high-temperature alloy block at a pressure of 1600-1800 MPa for 10 seconds; The heating is stopped and the product is cooled naturally to obtain a high-temperature alloy billet with a built-in coolant.