GH4169 alloy extra-large turbine disk skin structure and design method thereof

Abstract

This invention discloses a GH4169 alloy extra-large turbine disk skin structure and its design method, belonging to the field of metal material forming. The skin structure, with its forging surface radially along the center hole of the rough-machined turbine disk delivery part, includes a skin center section, a second transition section, and a first transition section connected sequentially from the inside to the outside. Both the first and second transition sections are conical surfaces, with rounded corners at their intersection. The angle between the generatrix of the first transition section and the vertical direction is θ1, and the angle between the generatrix of the second transition section and the vertical direction is θ2, where θ1 > θ2. The two-stage transition section design of the forging surface of the skin structure effectively disperses stress concentration in the central area of ​​the die during forging, significantly reducing local stress at the contact point between the die punch and the blank. The stress value can be controlled below 320 MPa, avoiding punch deformation or damage; reducing fatigue damage to the die under high stress, extending die service life, and reducing production costs.

Description

Technical Field

[0001] This invention belongs to the field of metal material forming, specifically relating to a GH4169 alloy extra-large turbine disk skin structure and its design method. Background Technology

[0002] Heavy-duty gas turbines, as core equipment in the energy sector, rely heavily on their turbine discs, which are critical hot-end components subjected to high temperatures (600-800℃), high pressures, and high-speed centrifugal forces, directly determining the turbine's efficiency and reliability. GH4169 alloy, due to its excellent comprehensive properties below 650℃, has become the preferred material for turbine disc forgings. Currently, 300MW-class GH4169 alloy extra-large turbine discs, after precision machining, have diameters exceeding 2 meters. Figure 1 The rough-machining delivery drawing of the GH4169 alloy extra-large turbine disc shown on display has an outer contour dimension of φ2140×400mm and a center hole diameter of φ390. The fabrication of this type of turbine disc forging is a first in China, with no prior production experience to draw upon. The official commissioning of my country's 800MN die forging press provides impetus for the fabrication of GH4169 alloy extra-large turbine disc forgings.

[0003] When forging this GH4169 alloy extra-large turbine disk, the forging shape must first be designed based on the rough machining delivery drawing, and then the mold must be prepared based on the forging contour. The center hole 1 of this type of forging typically uses a connecting bridge, and the current connecting structure 2 is as follows... Figure 1 As shown, the forging surface, along the radial direction of the center hole 1 of the rough-machined turbine disc delivery part, includes a connecting central section and a transition section connected sequentially from the inside to the outside. The transition section is a conical surface that gradually and smoothly extends outward from the connecting central section along the axial direction. Actual production revealed that this connecting section directly affects the safety of the GH4169 alloy extra-large turbine disc forging die, easily leading to excessive local stress in the upper and lower parts of the die center, posing a risk of instability. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a GH4169 alloy extra-large turbine disk skin structure and its design method, in order to solve the problem that traditional skin structures are prone to stress concentration in the central area of ​​the mold and have the risk of instability.

[0005] The technical solution adopted in this invention is: a GH4169 alloy extra-large turbine disk with a continuous skin structure, the forged surface of which, along the radial direction of the center hole of the rough-machined turbine disk delivery part, includes a continuous skin center section, a second transition section, and a first transition section connected sequentially from the inside to the outside. Both the first transition section and the second transition section are conical surfaces, and the intersection of the first transition section and the second transition section is rounded. The angle between the generatrix of the first transition section and the vertical direction is θ1, and the angle between the generatrix of the second transition section and the vertical direction is θ2, where θ1 > θ2.

[0006] By dispersing stress through two-stage transition sections and avoiding stress abrupt changes with rounded corners, stress concentration in the central area of ​​the die is reduced, thereby improving die life and forging safety.

[0007] Furthermore, 40°≤θ1≤60°; θ2=θ1-θ, where θ is the difference, 3°≤θ≤10°.

[0008] This angle range effectively disperses the stress in the central area of ​​the die during forging, ensuring smooth metal flow while avoiding excessively thick lining due to an excessively small angle or stress concentration due to an excessively large angle. Furthermore, the range of θ from 3° to 10° facilitates a natural transition between the two transition sections, preventing stress concentration caused by abrupt angle changes.

[0009] Furthermore, the thickness of the skin-connected structure at the center of the skin-connected section is the skin-connected thickness H0, where H0 = H - 4θ1.

[0010] Furthermore, taking the center of the center hole of the rough-machined part of the GH4169 alloy extra-large turbine disk as the origin, an X-axis is established along the diameter direction of the center hole, and a Y-axis is established along the height direction of the center hole to construct a plane rectangular coordinate system; the coordinates of the draft start point A of the first transition section are, where R is the radius of the center hole of the rough-machined part of the extra-large turbine disk, H is the height of the center hole of the rough-machined part of the extra-large turbine disk, δ is the design allowance, and the value range of δ is 8≤δ≤12.

[0011] The starting point is precisely located using coordinate expressions to ensure a smooth transition between the first transition section and the center hole of the forging, avoiding localized stress concentration caused by positional offset.

[0012] Furthermore, the coordinates of the draft start point B of the second transition section are b = -0.75R. 圆 +120, R 圆 The fillet radius between the second transition section and the center section of the connecting skin is 60 ≤ R. 圆 ≤100mm.

[0013] By precisely controlling the starting position of the second transition section using coordinate expressions, the stress distribution in the transition region is optimized, thereby enhancing structural stability.

[0014] The design method for the skin section of the aforementioned GH4169 alloy extra-large turbine disk includes the following steps:

[0015] Step 1: Using the center of the center hole of the rough-machined part of the GH4169 alloy extra-large turbine disk as the origin, establish an X-axis along the diameter direction of the center hole and a Y-axis along the height direction of the center hole to construct a plane rectangular coordinate system; determine the coordinates of the draft start point A of the skin structure, where the coordinates of A are , where R is the radius of the center hole of the rough-machined part of the extra-large turbine disk, H is the height of the center hole of the rough-machined part of the extra-large turbine disk, and δ is the design allowance, 8≤δ≤12;

[0016] Step 2: Taking the draft start point A as the starting point, determine the first transition section, where 40°≤θ1≤60°;

[0017] Step 3: Determine the thickness H0 of the skin-connected center segment based on the value of the step angle θ1, where H0 = H - 4θ1;

[0018] Step 4: Determine the coordinates of the draft start point B. The coordinates of B are given by [equation missing], where b = -0.75R. 圆 +120 b=-0.75R 圆 +120,

[0019] Step 5: Starting from the draft start point B, determine the second transition section. The second transition section forms a stepped angle θ2 with the inner wall of the center hole, where θ2 = θ1 - θ, and the value of the difference θ is in the range of 3° ≤ θ1 ≤ 10°.

[0020] Step 6: Round the corners at the intersection of the first transition segment and the second transition segment.

[0021] Furthermore, in step 5, the second transition section and the connecting skin center section are rounded at the draft start point B, with a fillet radius of R. 圆 .

[0022] Furthermore, the fillet radius in step 6 is the same as the fillet radius in step 5.

[0023] The beneficial effects of this invention are as follows: The forging surface with a continuous skin structure is designed with two-stage transition sections, which effectively disperses the stress concentration in the central area of ​​the die during forging, significantly reduces the local stress at the contact point between the die punch and the blank, and the stress value can be controlled below 320MPa, avoiding punch deformation or damage; it also reduces fatigue damage to the die under high stress, extends the die's service life, and reduces production costs. The rounded transition between the two stages avoids sudden stress changes, improves the stability of the forging process, and reduces the risk of equipment instability. Attached Figure Description

[0024] Figure 1 Delivery drawing for rough machining of GH4169 alloy extra-large turbine disc forgings;

[0025] Figure 2 This is a schematic diagram of a traditional skin-connected structure.

[0026] Figure 3 This is a schematic diagram of the GH4169 alloy extra-large turbine disk skin structure disclosed in this invention;

[0027] Figure 4 This is a schematic diagram of the mold stress distribution in Example 1.

[0028] In the diagram, the central hole is 1, the skin-connecting structure is 2, the first transition section is 21, the second transition section is 22, and the skin-connecting central section is 23. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0030] like Figure 3 The GH4169 alloy extra-large turbine disk connecting structure shown has a forged surface 2 along the radial direction of the center hole 1 of the rough-machined turbine disk delivery part. It includes a connecting center section 23, a second transition section 22, and a first transition section 21 connected sequentially from the inside to the outside. Both the first transition section 21 and the second transition section 22 are conical surfaces, and the intersection of the first transition section 21 and the second transition section 22 is rounded. The angle between the generatrix of the first transition section 21 and the vertical direction is θ1, and the angle between the generatrix of the second transition section 22 and the vertical direction is θ2, where θ1 > θ2.

[0031] Where 40°≤θ1≤60°; θ2=θ1-θ, θ is the difference, 3°≤θ≤10°.

[0032] The thickness of the skin-connected structure in the central segment 23 is the skin-connected thickness H0, where H0 = H - 4θ1.

[0033] With the center of the center hole 1 of the rough-machined part of the GH4169 alloy extra-large turbine disk as the origin, an X-axis is established along the diameter direction of the center hole 1, and a Y-axis is established along the height direction of the center hole to construct a plane rectangular coordinate system; the coordinates of the draft start point A of the first transition section 21 are (R+δ, H / 2+δ), where R is the radius of the center hole 1 of the rough-machined part of the extra-large turbine disk, H is the height of the center hole 1 of the rough-machined part of the extra-large turbine disk, and δ is the design allowance, with a value range of 8≤δ≤12.

[0034] The coordinates of the draft start point B of the second transition section 22 are (b, H0 / 2), where b = -0.75R. 圆 +120, R 圆 The fillet radius between the second transition section 22 and the connecting center section 23 is 60 ≤ R. 圆 ≤100mm.

[0035] Example 1

[0036] by Figure 1 Taking the GH4169 alloy extra-large turbine disk shown as an example, the radius of the center hole 1 in its rough machining delivery drawing is R = 180mm, and the height of the center hole 1 is H = 400mm.

[0037] Step 1: With the center of the center hole 1 of the forging as the center, and the radial direction as the X-axis ( Figure 1 (Horizontal direction), with the axis being the Y-axis ( Figure 1 Establish a rectangular coordinate system in the vertical direction. Determine the coordinates of the draft start point A as (190, 210), where δ is 10mm.

[0038] Step 2: Starting from draft start point A, draw the first transition segment 21, making its angle with the vertical direction θ1 = 50°.

[0039] Step 3: Calculate the thickness of the skin, H0 = 400 - 4 × 50 = 200 mm.

[0040] Step 4: Determine the fillet radius R between the second transition section 22 and the connecting skin center section 23. 圆 =70mm, calculate b = -0.75×70 + 120 = 67.5, determine the coordinates of the draft start point B as (67.5, 100).

[0041] Step 5: Starting from draft start point B, draw the second transition segment 22, with an angle θ2 = 45° and θ = 5° with the vertical direction.

[0042] Step 6: Round the corners at the intersection of the second transition segment 22 and the first transition segment 21 to form the final two-stage inclined skin structure.

[0043] Simulation verification shows that, Figure 4 As shown, the GH4169 alloy extra-large turbine disk with skin structure of the present invention has a stress of less than 320MPa at the contact part between the die punch and the blank, and there is no risk of punch deformation or damage.

[0044] Comparative Example 1

[0045] by Figure 1 Taking the GH4169 alloy extra-large turbine disc shown as an example, the radius R of the center hole 1 in its rough-machined delivery drawing is 180mm, and the height H of the center hole 1 is 400mm. That is, the GH4169 alloy extra-large turbine disc used in the comparative example is the same as that in Example 1. The difference is that Comparative Example 1 uses a traditional single-stage connection structure, meaning there is only one transition section. Under the same forging conditions, the peak stress in the central area of ​​the die reaches over 450MPa, posing a risk of punch deformation.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A GH4169 alloy extra-large turbine disk with integrated skin structure, wherein the diameter of the extra-large turbine disk after precision machining is greater than or equal to 2000 mm, characterized in that... Its forging surface is radially along the center hole (1) of the rough-machined delivery part of the turbine disc, including the connecting center section (23), the second transition section (22) and the first transition section (21) connected sequentially from the inside to the outside. The first transition section (21) and the second transition section (22) are both conical surfaces, and the intersection of the first transition section (21) and the second transition section (22) is rounded. The angle between the generatrix of the first transition section (21) and the vertical direction is θ1, and the angle between the generatrix of the second transition section (22) and the vertical direction is θ2, θ1 > θ2. The angle θ1 between the generatrix of the first transition section (21) and the vertical direction satisfies: 40° ≤ θ1 ≤ 60°. The angle θ2 between the generatrix of the second transition section (22) and the vertical direction satisfies: θ2 = θ1 - θ, where θ is the difference, 3° ≤ θ ≤ 10°.

2. The GH4169 alloy extra-large turbine disk skin structure according to claim 1, characterized in that, The thickness of the skin-connected structure in the central segment (23) is the skin-connected thickness H0, H0=H-4θ1.

3. The GH4169 alloy extra-large turbine disk skin structure according to claim 2, characterized in that, With the center of the center hole (1) of the rough-machined delivery part of the GH4169 alloy extra-large turbine disk as the origin, an X-axis is established along the diameter direction of the center hole (1), and a Y-axis is established along the height direction of the center hole to construct a plane rectangular coordinate system; the coordinates of the draft start point A of the first transition section (21) are (R+δ, H / 2+δ), where R is the radius of the center hole (1) of the rough-machined delivery part of the extra-large turbine disk, H is the height of the center hole (1) of the rough-machined delivery part of the extra-large turbine disk, and δ is the design allowance, with a value range of 8≤δ≤12.

4. The GH4169 alloy extra-large turbine disk skin structure according to claim 3, characterized in that, The coordinates of the draft start point B of the second transition section (22) are (b, H0 / 2), b = -0.75R. 圆 +120, R 圆 The fillet dimension between the second transition section (22) and the connecting skin center section (23) is 60 ≤ R. 圆 ≤100mm.

5. The design method for the skin-connecting portion of the GH4169 alloy extra-large turbine disk as described in claim 4, characterized in that, Includes the following steps: Step 1: Using the center hole (1) of the GH4169 alloy extra-large turbine disk rough-machined delivery part as the origin, establish the X-axis along the diameter direction of the center hole (1) and the Y-axis along the height direction of the center hole to construct a plane rectangular coordinate system; determine the coordinates of the draft start point A of the skin structure, the coordinates of A are (R+δ, H / 2+δ), where R is the radius of the center hole of the extra-large turbine disk rough-machined delivery part, H is the height of the center hole of the extra-large turbine disk rough-machined delivery part, δ is the design allowance, 8≤δ≤12; Step 2: Taking the draft start point A as the starting point, determine the first transition section (21), and 40°≤θ1≤60°; Step 3: Determine the thickness H0 of the skin-connected central segment (23) according to the value of the step angle θ1, H0 = H - 4θ1; Step 4: Determine the coordinates of the draft start point B, which is (b, H0 / 2), where b = -0.75R. 圆 +120 b=-0.75R 圆 +120; Step 5: Taking the draft start point B as the starting point, determine the second transition section (22). The second transition section (22) and the inner wall of the center hole form a stepped angle θ2, θ2=θ1-θ, and the value range of the difference θ is 3°≤θ1≤10°. Step 6: Round the corners at the intersection of the first transition segment (21) and the second transition segment (22).

6. The design method for the skin-connecting portion of the GH4169 alloy extra-large turbine disk according to claim 5, characterized in that, In step 5, the second transition section (22) and the connecting skin center section (23) are rounded at the draft start point B, with a fillet size of R. 圆 .

7. The design method for the skin-connecting portion of the GH4169 alloy extra-large turbine disk according to claim 5, characterized in that, The fillet radius in step 6 is the same as the fillet value in step 5.

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