A method for preparing nickel-based high-temperature alloy sheet and strip

Abstract

This invention provides a method for preparing nickel-based high-temperature alloy sheet and strip, comprising the following steps: (1) Preparation of nickel-based high-temperature alloy powder: mixing Ni-Al master alloy and Ni-Ti master alloy, then placing the mixture in a non-vacuum induction heating melting furnace for melting, allowing it to stand, and preparing nickel-based high-temperature alloy powder using a water atomization process, followed by pre-aging; (2) Slab forming: pressing the nickel-based high-temperature alloy powder into a slab; (3) Slab sintering and densification: sintering the slab at high temperature to densify it, obtaining a nickel-based high-temperature alloy sintered slab; (4) Processing of nickel-based high-temperature alloy sheet and strip: hot rolling the sintered slab first, then cold rolling it, to obtain nickel-based high-temperature alloy sheet and strip. The method for preparing nickel-based high-temperature alloy sheet and strip of this invention results in nano-sized Al-Ti intermetallic compound particles that are uniformly distributed in the matrix, with a size <50 nm, exhibiting high-temperature stability and significantly improving the service temperature.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy, specifically to a method for preparing nickel-based high-temperature alloy plates and strips. Background Technology

[0002] Nickel-based high-temperature alloy sheets and strips maintain good mechanical properties in high-temperature environments and do not undergo plastic deformation or softening at high temperatures; they have excellent corrosion resistance and wear resistance and can be used for a long time in harsh chemical media; they can be manufactured by forging, rolling, extrusion, stretching and other processing methods, and can also be connected with other materials by welding, brazing, threaded connection and other methods, and are widely used in aerospace, machinery and equipment, petrochemical, power, nuclear power and other fields.

[0003] However, traditional nickel-based superalloys are usually produced using special smelting and hot / cold working processes. The casting process is lengthy, requires large investments, and causes serious environmental pollution. At the same time, the high degree of alloying in traditional nickel-based superalloys results in a very narrow hot working window, making the yield of alloy plates and strips processed using traditional hot billet processes extremely low (≤20%). Summary of the Invention

[0004] The purpose of this invention is to overcome and supplement the shortcomings of existing technologies, and to provide a method for preparing nickel-based superalloy plates and strips. Al-Ti intermetallic compound particles are uniformly distributed in the matrix, with a size less than 50 nm. The nickel-based superalloy plates and strips exhibit excellent room temperature and high temperature performance, a short preparation and processing flow, high yield, high production efficiency, and are environmentally friendly. The technical solution adopted by this invention is as follows:

[0005] A method for preparing nickel-based high-temperature alloy sheet and strip, comprising the following steps:

[0006] (1) Preparation of nickel-based high-temperature alloy powder: Ni-Al master alloy and Ni-Ti master alloy are mixed, and then the mixture is placed in a non-vacuum induction heating melting furnace for melting, and then left to stand. After that, nickel-based high-temperature alloy powder is prepared by water atomization process and pre-aged at a temperature of 500-800 °C.

[0007] The specific process of water atomization is as follows: Molten nickel-based superalloy liquid is injected into the tundish. The high-pressure water pump in the water atomization device is started, and the high-pressure water atomization device begins operation. Subsequently, the superalloy melt in the tundish is directed through a beam and into the atomizer through a nozzle at the bottom of the tundish. A circumferential nozzle is used, with an atomization pressure of 30 MPa-100 MPa and a water flow rate of 60-150 m³ / h. 3Under the action of high-pressure water from the atomizer, the high-temperature alloy melt is continuously broken into fine droplets, which fall into the coolant in the device and quickly solidify into alloy powder. The atomized alloy powder is concentrated in the atomizing device, and after precipitation, filtration and drying, the desired nickel-based high-temperature alloy powder is obtained.

[0008] (2) Slab forming: The nickel-based high-temperature alloy powder obtained in step (1) is loaded into a rubber or silicone sleeve, and then the rubber or silicone sleeve is placed in a cold isostatic press for pressing to obtain a slab;

[0009] (3) Slab sintering densification: The slab obtained in step (2) is placed in a vacuum sintering furnace and densified by high-temperature sintering to obtain a nickel-based high-temperature alloy sintered slab;

[0010] (4) Processing of nickel-based high-temperature alloy plates and strips: The nickel-based high-temperature alloy sintered billet obtained in step (3) is first hot rolled and then cold rolled to obtain nickel-based high-temperature alloy plates and strips.

[0011] Preferably, in the method for preparing the nickel-based high-temperature alloy sheet and strip, the nickel-based high-temperature alloy powder in step (1) comprises Al 0.5-5 at%, Ti 0.5-4 at%, and the balance being Ni, by mass percentage, and the average particle size of the nickel-based high-temperature alloy powder is 5-75 μm.

[0012] Preferably, in the preparation method of the nickel-based high-temperature alloy plate and strip, the melting temperature in step (1) is 1450-1650 °C, the standing time is 10-40 min, the pressure of the atomizing medium water in the water atomization process is 30-100 MPa, and the pre-aging time is 2-10 h.

[0013] Preferably, in the method for preparing the nickel-based high-temperature alloy plate and strip, in step (1), after the nickel-based high-temperature alloy powder is pre-aged, AlTi, AlTi3, and Al3Ti intermetallic compound particles are precipitated with an average particle size of 10~50 nm.

[0014] Preferably, in the method for preparing the nickel-based high-temperature alloy plate and strip, the cold isostatic pressing pressure in step (2) is 80-150 MPa, the holding time is 1-5 min, the width of the slab is 100-1000 mm, and the thickness is 20-200 mm.

[0015] Preferably, in the method for preparing the nickel-based high-temperature alloy sheet and strip, the vacuum degree of the high-temperature sintering in step (3) is 10. -1 ~10 -3 Pa, sintering temperature is 1000~1200 ℃, holding time is 2~5 h.

[0016] Preferably, in the method for preparing the nickel-based high-temperature alloy plate and strip, the relative density of the nickel-based high-temperature alloy sintered billet in step (3) is 90% to 99%.

[0017] Preferably, in the method for preparing the nickel-based high-temperature alloy plate and strip, the preheating temperature of hot rolling in step (4) is 600-900 ℃, the single-pass reduction is 2-20 mm, and the rolling speed is 10-200 mm / s; the single-pass reduction of cold rolling is 0.1-1 mm, and the rolling speed is 1-20 mm / s.

[0018] Preferably, in the method for preparing the nickel-based high-temperature alloy plate and strip, the thickness of the nickel-based high-temperature alloy plate and strip in step (4) is 0.2 to 10 mm.

[0019] The technical principle of this invention is as follows: Ni-Al master alloy and Ni-Ti master alloy are used as raw materials, and Ni-Al-Ti nickel-based alloy powder is prepared by water atomization process. Al and Ti are dissolved in the nickel matrix at extremely high cooling rates. After low-temperature pre-aging, Al-Ti intermetallic nanophases are precipitated inside the powder particles. Nickel-based high-temperature alloy plates and strips are prepared by a combination of densification processes such as cold isostatic pressing, sintering and rolling. Since Al-Ti intermetallic compounds have extremely high thermodynamic stability, after being uniformly precipitated inside the powder particles, they will not grow significantly during subsequent sintering and rolling processes. Based on the dispersion strengthening effect, the high-temperature softening temperature, room temperature and high-temperature strength of the nickel matrix can be significantly improved.

[0020] Advantages of this invention:

[0021] (1) The method for preparing nickel-based high-temperature alloy plate and strip of the present invention provides that the nano-sized Al-Ti intermetallic compound particles in the prepared nickel-based high-temperature alloy powder are uniformly distributed in the matrix, with small size (<50 nm), high temperature stability, and significantly improved service temperature.

[0022] (2) The preparation method of nickel-based high-temperature alloy plate and strip of the present invention can effectively hinder dislocation movement at room temperature and high temperature by producing fine and uniform precipitated phase particles, thereby improving the room temperature and high temperature strength of the matrix and achieving a comprehensive performance higher than that of traditional nickel-based alloys.

[0023] (3) The process flow is short, the yield is high, the performance is consistent, the production efficiency is high, it is green and environmentally friendly, and it can realize industrial production. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments.

[0025] Example 1

[0026] The method for preparing nickel-based high-temperature alloy plates and strips in this embodiment includes the following steps:

[0027] (1) Preparation of nickel-based superalloy powder: Ni-Al master alloy and Ni-Ti master alloy were weighed according to the ratio for preparing Ni-0.5at% Al-0.5 at% Ti nickel-based superalloy, and placed in a non-vacuum induction heating melting furnace. The melting temperature was 1650 ℃. After being stirred evenly by electromagnetic stirring, the mixture was allowed to stand for 10 min. Nickel-based superalloy powder was prepared by water atomization process. The specific process of water atomization is as follows: The molten nickel-based superalloy was injected into the intermediate ladle. The high-pressure water pump in the water atomization device was started to allow the high-pressure water atomization device to start working. The superalloy melt in the intermediate ladle was passed through the beam and entered the atomizer through the nozzle at the bottom of the intermediate ladle. A circumferential nozzle was used with an atomization pressure of 30 MPa and a water flow rate of 150 m³ / h. 3 Under the action of high-pressure water from the atomizer, the high-temperature alloy melt is continuously broken into fine droplets, which fall into the coolant in the device and quickly solidify into alloy powder. The atomized alloy powder is concentrated in the atomizing device, and after precipitation, filtration and drying, the required nickel-based high-temperature alloy powder is obtained. The average particle size of the powder is 75 μm, and it is pre-aged at 800 °C for 2 h for later use.

[0028] (2) Slab forming: The nickel-based high-temperature alloy powder obtained in step (1) is loaded into a silicone sleeve and placed in a cold isostatic press for pressing. The cold isostatic pressing pressure is 150 MPa and the pressure is held for 1 min to obtain a slab with a width of 1000 mm and a thickness of 20 mm.

[0029] (3) Sintering and densification of slabs: The slabs obtained in step (2) are placed in a vacuum sintering furnace for high-temperature sintering and densification. The vacuum degree of sintering is 10. -1 Pa, sintering temperature of 1200 ℃, holding time of 2 h, to obtain nickel-based superalloy sintered billet with a relative density of 90%;

[0030] (4) Processing of nickel-based high-temperature alloy sheet and strip: The nickel-based high-temperature alloy sintered billet obtained in step (3) is first hot rolled at a preheating temperature of 600 ℃, a single pass reduction of 20 mm, and a rolling speed of 200 mm / s; then it is cold rolled at a single pass reduction of 1 mm and a rolling speed of 20 mm / s, and finally rolled into a nickel-based high-temperature alloy strip with a thickness of 0.2 mm.

[0031] The nickel-based superalloy strip obtained in this embodiment has a room temperature tensile strength of 1126 MPa, a tensile strength of 858 MPa at 650 ℃, and a tensile strength of 594 MPa at 850 ℃.

[0032] Example 2

[0033] The method for preparing nickel-based high-temperature alloy plates and strips in this embodiment includes the following steps:

[0034] (1) Preparation of nickel-based superalloy powder: Ni-Al master alloy and Ni-Ti master alloy were weighed according to the ratio for preparing Ni-3 at%Al-1 at%Ti nickel-based superalloy, and placed in a non-vacuum induction heating melting furnace. The melting temperature was 1450℃. After being stirred evenly by electromagnetic stirring, the mixture was allowed to stand for 30 min. Nickel-based superalloy powder was prepared by water atomization process. The specific process is as follows: The molten nickel-based superalloy was injected into the intermediate ladle. The high-pressure water pump in the water atomization device was started to allow the high-pressure water atomization device to start working. The superalloy melt in the intermediate ladle was passed through the beam and entered the atomizer through the nozzle at the bottom of the intermediate ladle. A circumferential nozzle was used with an atomization pressure of 100 MPa and a water flow rate of 60 m³ / h. 3 Under the action of high-pressure water from the atomizer, the high-temperature alloy melt is continuously broken into fine droplets, which fall into the coolant in the device and quickly solidify into alloy powder. The atomized alloy powder is concentrated in the atomizing device, and after precipitation, filtration and drying, the required nickel-based high-temperature alloy powder is obtained. The average particle size of the powder is 5 μm, and it is pre-aged at 500 °C for 10 h for later use.

[0035] (2) Slab forming: The nickel-based high-temperature alloy powder obtained in step (1) is loaded into a rubber sleeve and placed in a cold isostatic press for pressing. The cold isostatic pressing pressure is 80 MPa and the pressure is held for 5 min to obtain a slab with a width of 500 mm and a thickness of 200 mm.

[0036] (3) Sintering and densification of slabs: The slabs obtained in step (2) are placed in a vacuum sintering furnace for high-temperature sintering and densification, with a vacuum degree of 10. -3 Pa, sintering temperature of 1000 ℃, holding time of 5 h, to obtain nickel-based superalloy sintered billet with a relative density of 99%;

[0037] (4) Processing of nickel-based high-temperature alloy sheet and strip: The nickel-based high-temperature alloy sintered billet obtained in step (3) is first hot rolled at a preheating temperature of 900 ℃, a single pass reduction of 2 mm, and a rolling speed of 10 mm / s; then it is cold rolled at a single pass reduction of 0.1 mm and a rolling speed of 1 mm / s, and finally rolled into a nickel-based high-temperature alloy sheet with a thickness of 10 mm.

[0038] The nickel-based high-temperature alloy sheet obtained in this embodiment has a room temperature tensile strength of 1259 MPa, a tensile strength of 912 MPa at 650 ℃, and a tensile strength of 628 MPa at 850 ℃.

[0039] Example 3

[0040] The method for preparing nickel-based high-temperature alloy plates and strips in this embodiment includes the following steps:

[0041] (1) Preparation of nickel-based superalloy powder: Ni-Al master alloy and Ni-Ti master alloy were weighed according to the proportion for preparing Ni-5 at%Al-4 at%Ti nickel-based superalloy, and placed in a non-vacuum induction heating melting furnace. The melting temperature was 1600℃. After being stirred evenly by electromagnetic stirring, the mixture was allowed to stand for 30 min. Nickel-based superalloy powder was prepared by water atomization process. The specific process is as follows: The molten nickel-based superalloy was injected into the intermediate ladle. The high-pressure water pump in the water atomization device was started to allow the high-pressure water atomization device to start working. The superalloy melt in the intermediate ladle was passed through the beam and entered the atomizer through the nozzle at the bottom of the intermediate ladle. A circumferential nozzle was used with an atomization pressure of 70 MPa and a water flow rate of 80 m³ / h. 3 Under the action of high-pressure water from the atomizer, the high-temperature alloy melt is continuously broken into fine droplets, which fall into the coolant in the device and quickly solidify into alloy powder. The atomized alloy powder is concentrated in the atomizing device, and after precipitation, filtration and drying, the required nickel-based high-temperature alloy powder is obtained. The average particle size of the powder is 15 μm, and it is pre-aged at 700 ℃ for 5 h for later use.

[0042] (2) Slab forming: The nickel-based high-temperature alloy powder obtained in step (1) is loaded into a rubber sleeve and placed in a cold isostatic press for pressing. The cold isostatic pressing pressure is 120 MPa and the pressure is held for 2 min to obtain a slab with a width of 100 mm and a thickness of 50 mm.

[0043] (3) Sintering and densification of slabs: The slabs obtained in step (2) are placed in a vacuum sintering furnace for high-temperature sintering and densification, with a vacuum degree of 10. -2 Pa, sintering temperature of 1150 ℃, holding time of 3 h, to obtain nickel-based superalloy sintered billet with a relative density of 94%;

[0044] (4) Processing of nickel-based high-temperature alloy sheet and strip: The nickel-based high-temperature alloy sintered billet obtained in step (3) is first hot rolled at a preheating temperature of 800 ℃, a single pass reduction of 5 mm, and a rolling speed of 20 mm / s; then it is cold rolled at a single pass reduction of 0.3 mm and a rolling speed of 10 mm / s, and finally rolled into a nickel-based high-temperature alloy strip with a thickness of 0.5 mm.

[0045] The nickel-based superalloy strip obtained in this embodiment has a room temperature tensile strength of 1375 MPa, a tensile strength of 1039 MPa at 650 ℃, and a tensile strength of 764 MPa at 850 ℃.

[0046] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing nickel-based high-temperature alloy sheet and strip, characterized in that: Includes the following steps: (1) Preparation of nickel-based high-temperature alloy powder: Ni-Al master alloy and Ni-Ti master alloy are mixed, and then the mixture is placed in a non-vacuum induction heating melting furnace for melting, and then left to stand. After that, nickel-based high-temperature alloy powder is prepared by water atomization process and pre-aged at a temperature of 500-800 °C. (2) Slab forming: The nickel-based high-temperature alloy powder obtained in step (1) is loaded into a rubber or silicone sleeve, and then the rubber or silicone sleeve is placed in a cold isostatic press for pressing to obtain a slab; (3) Slab sintering densification: The slab obtained in step (2) is placed in a vacuum sintering furnace and densified by high-temperature sintering to obtain a nickel-based high-temperature alloy sintered slab; (4) Processing of nickel-based high-temperature alloy sheet and strip: The nickel-based high-temperature alloy sintered billet obtained in step (3) is first hot rolled and then cold rolled to obtain nickel-based high-temperature alloy sheet and strip. The nickel-based superalloy powder in step (1) comprises Al 0.5-5 at%, Ti 0.5-4 at%, and the balance is Ni. After pre-aging, AlTi, AlTi3, and Al3Ti intermetallic compound particles are precipitated from the nickel-based superalloy powder in step (1). The average particle size of the AlTi, AlTi3, and Al3Ti intermetallic compound particles in step (1) is 10~50 nm.

2. The method for preparing nickel-based high-temperature alloy plate and strip as described in claim 1, characterized in that: The average particle size of the nickel-based superalloy powder is 5–75 μm.

3. The method for preparing nickel-based high-temperature alloy plate and strip as described in claim 1, characterized in that: The melting temperature in step (1) is 1450–1650 °C, the standing time is 10–40 min, the pressure of the atomizing medium water in the water atomization process is 30–100 MPa, and the pre-aging time is 2–10 h.

4. The method for preparing nickel-based high-temperature alloy plate and strip as described in claim 1, characterized in that: The cold isostatic pressing pressure in step (2) is 80-150 MPa, and the holding time is 1-5 min; the width of the slab is 100-1000 mm and the thickness is 20-200 mm.

5. The method for preparing nickel-based high-temperature alloy plate and strip as described in claim 1, characterized in that: The vacuum degree of high-temperature sintering in step (3) is 10 -1 ~10 -3 Pa, the sintering temperature is 1000~1200 ℃, and the holding time is 2~5 h.

6. The method for preparing nickel-based high-temperature alloy plate and strip as described in claim 1, characterized in that: In step (3), the relative density of the nickel-based superalloy sintered billet is 90% to 99%.

7. The method for preparing nickel-based high-temperature alloy sheet and strip as described in claim 1, characterized in that: In step (4), the preheating temperature of hot rolling is 600-900 ℃, the single-pass reduction is 2-20 mm, and the rolling speed is 10-200 mm / s; the single-pass reduction of cold rolling is 0.1-1 mm, and the rolling speed is 1-20 mm / s.

8. The method for preparing nickel-based high-temperature alloy sheet and strip as described in claim 1, characterized in that: In step (4), the thickness of the nickel-based high-temperature alloy plate and strip is 0.2 to 10 mm.