Forming method for double-crown powder superalloy blade blank

Abstract

The present invention relates to a forming method for a blank of a double-crown powder superalloy blade. In this method, both the blade body part and the blade crown part are formed by two sets of actions of a set of molds. After the blade crown part is cured and formed, high-pressure torsion is used to drive the torsion of the blade body part, and the mold is used to form the blade body part, further optimizing the structure of the blade body part. In addition, torsion is completed through the frictional force between the mold and the blade crown part. Under the action of the frictional force, the surface of the blade crown part is indirectly surface-strengthened, the grain structure is further refined, and plastic deformation with a depth of 5-10 mm in the surface layer structure is achieved, optimizing the blade performance. The method of the present invention can not only realize the powder metallurgy one-time forming of superalloy blades, but also realize the diversification of blade performance and avoid multiple heat treatments.

Description

Technical Field

[0001] The present invention relates to a forming method for a double-crown powder superalloy blade blank, belonging to the technical field of blade processing and manufacturing. Background Art

[0002] γ-TiAl intermetallic compound has a series of advantages such as low density, high specific strength and specific stiffness, and good high-temperature performance. It is generally considered that its long-term service temperature can even reach 750°C - 800°C (typical high-temperature performance data: at 800°C, the tensile strength is about 500 MPa). On the one hand, γ-TiAl intermetallic compound can replace conventional Ti-based alloys, thereby increasing the service temperature of the material; on the other hand, it can replace Ni-based superalloys to achieve the purpose of weight reduction, and the weight reduction effect is more obvious than that of Ti2AlNb alloy, which is very attractive for meeting the high-temperature service requirements and weight reduction requirements of high-performance aeroengines. Summary of the Invention

[0003] The present invention is precisely designed and provided with a forming method for a double-crown powder superalloy blade blank in view of the above-mentioned existing technical situation. Its purpose is to form a double-crown superalloy blade blank by powder metallurgy in one step, and achieve the difference in the tissue properties of the blade body and blade crown parts, avoiding multiple subsequent heat treatments.

[0004] To achieve the above purpose, the content of the technical solution of the present invention is as follows:

[0005] The steps of the forming method for the double-crown powder superalloy blade blank are as follows:

[0006] Step 1: Preparation of the forming die

[0007] The die used in this forming method includes a blade forming sleeve 2 and coaxial blade crown forming sleeves 3 on both sides of it. The blade crown forming sleeves 3 can rotate around this axis. Heating induction coils 4 are arranged around the blade forming sleeve 2 and the blade crown forming sleeves 3. Above and below the blade forming sleeve 2, there are a blade body forming upper die 5 and a blade body forming lower die 1, and the blade body forming upper die 5 and the blade body forming lower die 1 can make a feeding movement towards each other perpendicular to the above-mentioned axis;

[0008] Step 2: Solidification of the blade body part

[0009] The 400-mesh superalloy powder is transported into the blade forming sleeve 2 through the channels at both ends of the blade forming sleeve 2, and then the 200-mesh superalloy powder is transported into the shroud forming sleeve 3 through the channels at both ends of the blade forming sleeve 2. The induction coil 4 around the blade forming sleeve 2 is started. When the temperature reaches 1000 - 1150 °C, the lower die 1 for blade forming and the upper die 5 for blade forming move upward and downward respectively to press the blade forming sleeve 2 with a pressure of 700 - 1000 MPa, keep the temperature and pressure for 1 - 1.5 h, and then reduce the temperature of the blade forming sleeve 2 part to 500 - 700 °C. At the same time, the lower die 1 for blade forming and the upper die 5 for blade forming remain stationary;

[0010] Step 3: Solidification of the shroud part

[0011] The induction coil 4 around the shroud forming sleeve 3 is started. When the temperature reaches 1000 - 1150 °C, a pressure of 700 - 1000 MPa is applied to press the shroud forming sleeve 3, making the shroud forming sleeve 3 shrink and deform centripetally, keep the temperature and pressure for 1 - 1.5 h, and then reduce the temperature of the shroud forming sleeve 3 part to 800 - 900 °C while keeping its shape unchanged;

[0012] Step 4: Twisting of the shroud part and forming of the blade part

[0013] Reduce the pressure of the blade forming sleeve 2 and the shroud forming sleeve 3 parts to 100 - 300 MPa, and then rotate the shroud forming sleeves 3 on both sides of the blade forming sleeve 2 clockwise and counterclockwise respectively. At the same time, the lower die 1 for blade forming and the upper die 5 for blade forming move downward and upward respectively, but still keep the lower die 1 for blade forming and the upper die 5 for blade forming in contact with the twisted blade forming sleeve 2, and control the contact pressure within the range of 100 - 300 MPa, so that the blade part in the blade forming sleeve 2 is formed during the reverse rotation of the two shroud forming sleeves 3. After the forming is completed, stop the rotation and the induction coil 4 stops working;

[0014] Step 5: Post-treatment after blade forming

[0015] After the blade forming sleeve 2 and the shroud forming sleeve 3 are cooled to room temperature, take them out. After sandblasting and polishing, a double-crown powder superalloy blade blank is obtained.

[0016] During implementation, there is an interference fit between the blade forming sleeve 2 and the coaxially arranged shroud forming sleeves 3 on both sides of it.

[0017] During implementation, the particle size of the superalloy powder transported into the blade forming sleeve 2 is 400 mesh.

[0018] During implementation, the particle size of the superalloy powder transported into the shroud forming sleeve 3 is 200 mesh.

[0019] Furthermore, the superalloy powder within the blade forming sleeve 2 and the shroud forming sleeve 3 is of the same material.

[0020] Furthermore, the material of the superalloy powder is a γ-TiAl intermetallic compound.

[0021] During implementation, in step four, the shroud forming dies 3 on both sides of the blade forming sleeve 2 rotate clockwise and counterclockwise at a rotational speed of 30 - 50 rad / s for a time of 60 - 90 s.

[0022] During implementation, in step four, when the shroud forming sleeves 3 on both sides of the blade forming sleeve 2 rotate clockwise and counterclockwise respectively, the component applying the rotational driving force forms and maintains relative movement during contact with the shroud forming sleeve 3.

[0023] The characteristics and beneficial effects of the technical solution of the present invention are as follows:

[0024] 1. Different particle sizes of powder superalloys are used for the blade body part and the shroud part of the double-shroud superalloy blade blank, enabling the shroud part and the blade body part of the formed superalloy blade blank to have dual structures and dual properties, avoiding multiple heat treatment processes after forming, and improving production efficiency;

[0025] 2. By stepwise forming the blade body part and the shroud part of the double-shroud superalloy blade blank, one-time completion of blade blank forming and stress relief annealing is achieved. By utilizing the length of the blade blank and the differential control of the induction coil, and reasonably leveraging heat conduction, the forming cost is reduced;

[0026] 3. The forming of the blade blank is different from existing rapid forming. Both the blade body part and the shroud part are formed by two sets of actions of a set of molds. After the shroud part is solidified and formed, high-pressure torsion is used to drive the torsion of the blade body part, and the mold is used to form the blade body part, further optimizing the structure of the blade body part;

[0027] 4. Torsion is completed through the frictional force between the mold and the shroud part. Under the action of the frictional force, the surface of the shroud part is indirectly surface strengthened, the grain structure is further refined, and plastic deformation with a depth of 5 - 10 mm of the surface layer structure is achieved, optimizing the blade performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a double-shroud superalloy blade;

[0029] Figure 2 Schematic diagram of forming a double-shroud superalloy blade blank according to the technical solution of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0031] The steps of preparing a double-crown powder superalloy blade blank by using the method of the present invention are as follows:

[0032] Step 1: Preparation of superalloy powder and forming die

[0033] Prepare sufficient amounts of fresh 200-mesh and 400-mesh superalloy powders for standby respectively. The material of the superalloy powder is γ-TiAl intermetallic compound;

[0034] The die used in this forming method includes a blade forming sleeve 2 and coaxial crown forming sleeves 3 on both sides thereof. The crown forming sleeve 3 can rotate around the axis. An induction coil 4 for heating is arranged around the blade forming sleeve 2 and the crown forming sleeves 3. A blade body upper die 5 and a blade body lower die 1 are arranged above and below the blade forming sleeve 2. The blade body upper die 5 and the blade body lower die 1 can make opposite feeding movements perpendicular to the axial direction;

[0035] Step 2: Solidification of the blade body part

[0036] Transport the 400-mesh superalloy powder into the blade forming sleeve 2 through the channels at both ends of the blade forming sleeve 2, and then transport the 200-mesh superalloy powder into the crown forming sleeves 3 through the channels at both ends of the blade forming sleeve 2. Start the induction coil 4 around the blade forming sleeve 2. When the temperature reaches 1000 °C, make the blade body lower die 1 and the blade body upper die 5 move upward and downward respectively to press the blade forming sleeve 2, with a pressure of 700 MPa, keep the temperature and pressure for 1 h, and then reduce the temperature of the blade forming sleeve 2 part to 500 °C. At the same time, the blade body lower die 1 and the blade body upper die 5 remain stationary;

[0037] Step 3: Solidification of the crown part

[0038] Start the induction coil 4 around the crown forming sleeve 3. When the temperature reaches 1000 °C, apply a pressure of 700 MPa to press the crown forming sleeve 3, so that the crown forming sleeve 3 is in a contracted state and deforms centripetally, keep the temperature and pressure for 1 h, and then reduce the temperature of the crown forming sleeve 3 part to 800 °C, while keeping its shape unchanged;

[0039] Step 4: Twisting of the crown part and forming of the blade body part

[0040] Reduce the pressure at the blade forming jacket 2 and the shroud forming jacket 3 parts to 100 MPa. Then, rotate the shroud forming jackets 3 on both sides of the blade forming jacket 2 clockwise and counterclockwise respectively at a rotational speed of 30 - 50 rad / s for 60 s. At the same time, the blade body forming lower die 1 and the blade body forming upper die 5 move downward and upward respectively, but still keep the blade body forming lower die 1 and the blade body forming upper die 5 in contact with the twisted blade forming jacket 2, and control the contact pressure within 100 MPa to ensure the blade part profile, so that the blade body part in the blade forming jacket 2 is formed during the reverse rotation of the two shroud forming jackets 3. After the forming is completed, stop the rotation and the induction coil 4 stops working;

[0041] The above-mentioned clockwise and counterclockwise rotations of the shroud forming jacket 3 are achieved through the frictional force between the mold and the shroud forming jacket 3. Under the action of the frictional force, the surface of the shroud part is indirectly surface-strengthened, the grain structure is further refined, and plastic deformation with a depth of 5 - 10 mm in the surface layer structure is achieved, optimizing the blade performance.

[0042] Step Five: Post-treatment of the formed blade

[0043] After the blade forming jacket 2 and the shroud forming jacket 3 are cooled to room temperature, take them out. After sandblasting and polishing, a double-shroud powder superalloy blade blank is obtained.

Claims

1. A forming method for a double-crown powder superalloy blade blank, characterized in that: The steps of this forming method are as follows: Step 1: Preparation of the forming die The die used in this forming method includes a blade forming sleeve (2) and coaxial shroud forming sleeves (3) on both sides of the blade forming sleeve (2). The shroud forming sleeves (3) can rotate around the axis. An induction coil (4) for heating is arranged around the blade forming sleeve (2) and the shroud forming sleeves (3). Above and below the blade forming sleeve (2), there are an airfoil upper die (5) and an airfoil lower die (1). The airfoil upper die (5) and the airfoil lower die (1) can move towards each other perpendicular to the said axis; Step 2: Solidification of the airfoil part The 400-mesh superalloy powder is conveyed into the blade forming sleeve (2) through the channels at both ends of the blade forming sleeve (2), and then the 200-mesh superalloy powder is conveyed into the shroud forming sleeves (3) through the channels at both ends of the blade forming sleeve (2). The induction coil (4) around the blade forming sleeve (2) is started. When the temperature reaches 1000 - 1150 °C, the airfoil lower die (1) and the airfoil upper die (5) move upwards and downwards respectively to press the blade forming sleeve (2), with a pressure of 700 - 1000 MPa. Keep the pressure and temperature for 1 - 1.5 h, and then reduce the temperature of the blade forming sleeve (2) part to 500 - 700 °C. At the same time, the airfoil lower die (1) and the airfoil upper die (5) remain stationary; Step 3: Solidification of the shroud part The induction coil (4) around the shroud forming sleeve (3) is started. When the temperature reaches 1000 - 1150 °C, a pressure of 700 - 1000 MPa is applied to press the shroud forming sleeve (3), making the shroud forming sleeve (3) shrink and deform centripetally. Keep the pressure and temperature for 1 - 1.5 h, and then reduce the temperature of the shroud forming sleeve (3) part to 800 - 900 °C, while keeping its shape unchanged; Step 4: Twisting of the shroud part and forming of the airfoil part Reduce the pressure of the blade forming sleeve (2) and the shroud forming sleeves (3) parts to 100 - 300 MPa, and then rotate the shroud forming sleeves (3) on both sides of the blade forming sleeve (2) clockwise and counterclockwise respectively. At the same time, the airfoil lower die (1) and the airfoil upper die (5) move downwards and upwards respectively, but still keep the airfoil lower die (1) and the airfoil upper die (5) in contact with the twisted blade forming sleeve (2), and control the contact pressure within the range of 100 - 300 MPa, so that the airfoil part in the blade forming sleeve (2) is formed during the reverse rotation of the two shroud forming sleeves (3). After the forming is completed, stop the rotation and the induction coil (4) stops working; Step 5: Post-treatment after blade forming After the blade forming sleeve (2) and the shroud forming sleeves (3) are cooled to room temperature, take them out. After sandblasting and polishing, a double-shroud powder superalloy blade blank is obtained.

2. The forming method of the double-crown powder superalloy blade blank according to claim 1, characterized in that: There is an interference fit between the blade forming sleeve (2) and the coaxial shroud forming sleeves (3) on both sides of the blade forming sleeve (2).

3. The forming method of the double-crown powder superalloy blade blank according to claim 1 or 2, characterized in that: The superalloy powders in the blade forming sleeve (2) and the shroud forming sleeves (3) are of the same material.

4. The forming method of the double-crown powder superalloy blade blank according to claim 1 or 2, characterized in that: The material of the superalloy powder is γ-TiAl intermetallic compound.

5. The forming method of the double-crown powder superalloy blade blank according to claim 1, characterized in that: In step four, the rotational speeds of the shroud forming sleeves (3) on both sides of the blade forming sleeve (2) rotating clockwise and counterclockwise are 30-50 rad / s, and the time is 60-90 s.

6. The forming method of the double-crown powder superalloy blade blank according to claim 1, characterized in that: In step four, when the shroud forming sleeves (3) on both sides of the blade forming sleeve (2) rotate clockwise and counterclockwise respectively, the component applying the rotational driving force forms and maintains relative motion with the shroud forming sleeve (3) during the contact process.

Images