A method for manufacturing a water bucket in the low stress area at the root of an impact runner

Abstract

The present invention discloses a method for manufacturing a low-stress bucket in the root of an impact runner. The method includes establishing a root bucket model of a target impact runner, calculating the stress distribution of the root bucket, demarcating stress zones, dividing the root low-stress bucket into a vertical welding zone and an arc welding zone, using additive equipment to execute a first automatic additive program to additively manufacture the vertical welding zone of the root low-stress bucket on a center body forging, welding a support plate to the inner edge of the vertical welding zone, and using additive equipment to execute a second automatic additive program to additively manufacture the arc welding zone of the root low-stress bucket on the center body forging via the support plate. The present invention divides the root low-stress bucket of the impact runner into a vertical welding zone and an arc welding zone. After completing additive welding in the vertical welding zone, additive welding is performed on the arc welding zone by providing a support plate, thereby avoiding molten pool flow during additive manufacturing of the root low-stress bucket, thereby improving the manufacturing quality of the root bucket.

Description

Technical Field

[0001] The present invention relates to the technical field of impact runners, and in particular to a method for manufacturing a water bucket in a low-stress zone at the root of an impact runner. Background Art

[0002] With the development of high-head, large-capacity Pelton turbines, the size of the runner, the core component of the Pelton turbine, has grown. Pelton runners primarily consist of a center body and buckets. For large-capacity Pelton runners, the industry consensus is that the center body should be forged. During operation, Pelton runners are subjected to the cyclic impact of high-speed water flow, particularly at the base of the buckets, which is subject to typical fatigue loads and is the area most stressed. Because forgings undergo repeated forging during manufacturing, defects such as as-cast porosity caused by the metal smelting process are eliminated, optimizing the microstructure. To ensure safe and reliable operation of the runner, forgings are also required at the base of the runner buckets.

[0003] like Figure 1 As shown in the figure, the existing manufacturing process for impact runners involves machining the root bucket from a single forging. The runner is made of martensitic stainless steel, which has excessive forging resistance. The theoretical maximum thickness of martensitic stainless steel forged by the largest domestic open-die forging press (18,500-ton press) is no more than 1,200 mm, making it incapable of manufacturing thicker forgings. However, with technological advancements and the needs of domestic power plants, there is an urgent need to expand the capacity of impact units to the million-kilowatt level, requiring a corresponding forged blank thickness of 1,600 mm. This demand far exceeds the manufacturing capacity of these equipment.

[0004] like Figure 2 As shown in the figure, the applicant has proposed a process for manufacturing the root buckets of an impact runner. This process uses partial forgings to create the high-stress areas of the center body and root buckets, and then uses additive manufacturing to create the low-stress root buckets on the center body. This process can address the technical issues of large forging thickness and poor forging quality associated with the use of monolithic forgings in existing impact runner manufacturing. However, in this process, the additive manufacturing of the root buckets on the center body causes the inclination angle of the low-stress root buckets to be too large, which can easily cause the molten pool to flow during the additive manufacturing process, seriously affecting the manufacturing quality of the impact runner root buckets. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for manufacturing a water bucket in the low-stress area at the root of an impact runner, aiming to solve the technical problem of low manufacturing quality of the root water bucket caused by molten pool flow when the water bucket in the low-stress area of ​​the root of the impact runner is manufactured by additive manufacturing.

[0006] To achieve the above-mentioned object, the present invention provides a method for manufacturing a water bucket in a low-stress zone at the root of an impact runner, the method comprising the following steps:

[0007] S1: Establish a root bucket model of the target impact runner, calculate the root bucket stress distribution, and divide the low stress area;

[0008] S2: Dividing the root low stress area bucket into a vertical welding area and an arc welding area according to the root low stress area bucket in the root bucket model;

[0009] S3: generating a first automatic additive program corresponding to the vertical welding area and a second automatic additive program corresponding to the arc welding area respectively;

[0010] S4: using the additive equipment to execute a first automatic additive process to additively manufacture a vertical welding area of ​​the root low stress zone bucket on the center body forging;

[0011] S5: Welding a support plate at the inner edge of the vertical welding area, using the additive equipment to execute a second automatic additive process, and additively manufacturing the arc-shaped welding area of ​​the root low-stress zone bucket on the center body forging through the support plate.

[0012] Optionally, in step S2, the vertical welding area is configured as an area of ​​the root low stress zone hopper where the uppermost welding segment and the lowermost welding segment meet the preset misalignment requirements when performing each layer of additive manufacturing, and the arc welding area is an area of ​​the root low stress zone hopper where the uppermost welding segment and the lowermost welding segment do not meet the preset misalignment requirements when performing each layer of additive manufacturing.

[0013] Optionally, during the process of additive manufacturing the arc-shaped welding area on the center body forging, the support plate abuts against a preset position of the arc-shaped welding area.

[0014] Optionally, step S4 specifically includes:

[0015] S401: Determine the welding position of the water bucket in the root low stress area of ​​the center body forging;

[0016] S402: Executing a first automatic additive process using the additive equipment to perform additive manufacturing on a vertical welding area of ​​the root low stress zone bucket at a welding position on the center body forging.

[0017] Optionally, in step S402 , before additive manufacturing is performed on the vertical welding area of ​​the root low stress zone bucket at the welding position on the center body forging, position calibration is performed on the additive equipment and the center body forging.

[0018] Optionally, step S1 specifically includes:

[0019] S101: Acquire test data of a target impact wheel, and divide the target impact wheel into a root bucket high stress area and a root bucket low stress area according to the test data;

[0020] S102: Establishing an overall model of a target impact runner, and determining a root bucket model of the target impact runner based on a root bucket high stress area and a root bucket low stress area of ​​the target impact runner.

[0021] Optionally, the test data includes stress distribution test data and processing accessibility test data of the target impact wheel.

[0022] An embodiment of the present invention provides a method for manufacturing a low-stress bucket in the root of an impact runner. The method includes establishing a root bucket model of a target impact runner, dividing the root low-stress bucket into a vertical welding area and a curved welding area, generating a first automatic additive program and a second automatic additive program, respectively, using the additive equipment to execute the first automatic additive program, additively manufacturing the vertical welding area of ​​the root low-stress bucket on a center body forging, welding a support plate to the inner edge of the vertical welding area, and executing the second automatic additive program using the additive equipment to additively manufacture the curved welding area of ​​the root low-stress bucket on the center body forging using the support plate. The present invention divides the root low-stress bucket of the impact runner into a vertical welding area and a curved welding area, and after completing additive welding in the vertical welding area, additively welding the curved welding area by providing a support plate. This solves the technical problem of low manufacturing quality of the root bucket of the impact runner caused by molten pool flow when additively manufacturing the root low-stress bucket of the impact runner. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a schematic diagram showing the principle of manufacturing an existing impact runner through integral forging.

[0024] Figure 2 This is a schematic diagram of the principle of manufacturing the impact-type runner root bucket using some forgings of the present invention.

[0025] Figure 3 The figure is a schematic flow chart of the method for manufacturing the water bucket in the low stress zone at the root of the impact wheel of the present invention.

[0026] Figure 4 Schematic diagram of the present invention using a support plate to perform additive manufacturing on an arc-shaped welding area.

[0027] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0028] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] At present, in the relevant technical field, when the additive manufacturing of the root low-stress zone water bucket is performed on the center body, the inclination angle of the root low-stress zone water bucket is too large, which easily causes the molten pool to flow during the additive manufacturing, seriously affecting the manufacturing quality of the impact runner root water bucket.

[0030] To address this issue, various embodiments of the present invention are provided for a method for manufacturing a low-stress bucket in the root of an impact runner. The method divides the low-stress bucket in the root of an impact runner into a vertical welding area and an arc-shaped welding area. After additive welding is completed in the vertical welding area, a support plate is provided to perform additive welding in the arc-shaped welding area. This method solves the current technical problem of low manufacturing quality of the low-stress bucket in the root of an impact runner caused by molten pool flow when additively manufacturing the low-stress bucket.

[0031] The embodiment of the present invention provides a method for manufacturing a water bucket in a low stress zone at the root of an impact wheel, referring to Figure 3 , Figure 3 Schematic diagram of the process of manufacturing the water bucket in the low stress zone at the root of the impact wheel according to the first embodiment of the present invention.

[0032] In this embodiment, the method for manufacturing the water bucket in the low stress zone at the root of the impact wheel includes the following steps:

[0033] S1: Establish a root bucket model of the target impact wheel, calculate the root bucket stress distribution, and divide the low stress area.

[0034] It should be noted that when establishing the root bucket model of the target impact wheel, it is necessary to delineate the root bucket high stress area and the root bucket low stress area based on the stress distribution of the target impact wheel and the processing accessibility simulation analysis results.

[0035] Specifically, by obtaining the test data of the target impact runner, the root bucket high stress area and the root bucket low stress area of ​​the target impact runner are divided according to the test data, and then the overall model of the target impact runner is established. Based on the root bucket high stress area and the root bucket low stress area of ​​the target impact runner, the root bucket model of the target impact runner is determined, and the root bucket model composed of the root bucket high stress area and the root bucket low stress area is determined.

[0036] The test data include stress distribution test data and processing accessibility test data of the target impact runner.

[0037] S2: According to the root low stress area bucket in the root bucket model, the root low stress area bucket is divided into a vertical welding area and an arc welding area.

[0038] To address the issue of molten pool flow caused by the water bucket in the root low-stress area during material addition on the center body, which in turn affects the production quality of the water bucket in the root low-stress area, this embodiment divides the water bucket in the root low-stress area into a vertical welding area that does not cause molten pool flow and an arc welding area that does cause molten pool flow.

[0039] Furthermore, when performing the subsequent additive welding of the water bucket in the low-stress zone of the root, the vertical welding area and the arc welding area are welded independently, which can improve the additive welding efficiency as much as possible while solving the problem of molten pool flow.

[0040] Specifically, the vertical welding area is configured as the area of ​​the root low-stress zone where the top weld segment and the bottom weld segment meet the preset misalignment requirement during each layer of additive manufacturing. The arc welding area is configured as the area of ​​the root low-stress zone where the top weld segment and the bottom weld segment do not meet the preset misalignment requirement during each layer of additive manufacturing.

[0041] S3: Generate a first automatic additive program corresponding to the vertical welding area and a second automatic additive program corresponding to the arc welding area respectively.

[0042] After the root low stress area bucket in the root bucket model is divided into a vertical welding area and an arc welding area, a first automatic additive program corresponding to the vertical welding area and a second automatic additive program for the arc welding area can be generated according to the divided areas, so that the additive equipment can use independent welding for the vertical welding area and the arc welding area when executing the additive program.

[0043] S4: Executing a first automatic additive process using the additive equipment to perform additive manufacturing on a vertical welding area of ​​a root low stress zone bucket on a center body forging.

[0044] It should be noted that the additive manufacturing of the vertical welding area is carried out by determining the welding positions of the water buckets in the root low stress area on the center body forging, and then using the additive equipment to execute the first automatic additive program to additively manufacture the vertical welding area of ​​the water buckets in the root low stress area at the welding positions on the center body forging.

[0045] S5: Welding a support plate at the inner edge of the vertical welding area, using the additive equipment to execute a second automatic additive process, and additively manufacturing the arc-shaped welding area of ​​the root low-stress zone bucket on the center body forging through the support plate.

[0046] It should be noted that if Figure 4As shown, during additive manufacturing of the curved weld area on the center body forging, the support plate abuts a predetermined portion of the curved weld area. This predetermined portion can be selected based on the size of the root low-stress bucket and the weight of the material. The support plate abuts the curved weld area to provide upward support during additive manufacturing, preventing the molten pool from flowing.

[0047] In a preferred embodiment, before performing additive manufacturing on the vertical welding area of ​​the root low stress zone bucket at the welding position on the center body forging, it is also necessary to perform position calibration on the additive equipment and the center body forging.

[0048] This embodiment provides a method for manufacturing a water bucket in the low-stress area at the root of an impact runner. By setting a support plate to perform additive welding on the arc welding area, it solves the technical problem of low manufacturing quality of the root water bucket caused by molten pool flow when the water bucket in the low-stress area at the root of the impact runner is currently manufactured by additive manufacturing.

[0049] The above are only preferred embodiments of the invention and are not intended to limit the patent scope of the invention. Any equivalent structure or equivalent process transformation made using the contents of the invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the invention.

Claims

1. A method for manufacturing a water bucket in a low stress zone at the root of an impact runner, characterized in that: The method comprises the following steps: S1: Establish a root bucket model of the target impact runner, calculate the root bucket stress distribution, and divide the low stress area; S2: Dividing the root low stress zone bucket in the root bucket model into a vertical welding area and an arc welding area; the vertical welding area is configured as an area of ​​the root low stress zone bucket where the uppermost welding segment and the lowermost welding segment meet a preset misalignment requirement when performing additive manufacturing of each layer; and the arc welding area is an area of ​​the root low stress zone bucket where the uppermost welding segment and the lowermost welding segment do not meet the preset misalignment requirement when performing additive manufacturing of each layer; S3: generating a first automatic additive program corresponding to the vertical welding area and a second automatic additive program corresponding to the arc welding area respectively; S4： S401: Determine the welding position of the water bucket in the root low stress area of ​​the center body forging; S402: Using an additive manufacturing device to execute a first automatic additive manufacturing process, additive manufacturing is performed on a vertical welding area of ​​a root low stress zone bucket at a welding position on the center body forging; S5: Welding a support plate at the inner edge of the vertical welding area, using the additive equipment to execute a second automatic additive program, and additively manufacturing the arc welding area of ​​the water bucket in the root low stress area on the center body forging through the support plate; during the process of additively manufacturing the arc welding area on the center body forging, the support plate abuts against a preset position of the arc welding area.

2. The method for manufacturing the low stress zone bucket at the root of an impact wheel according to claim 1, characterized in that: In step S402 , before additive manufacturing is performed on the vertical welding area of ​​the root low stress zone bucket at the welding position on the center body forging, the position of the additive equipment and the center body forging is calibrated.

3. The method for manufacturing a low stress bucket at the root of an impact wheel according to claim 1, wherein: The step S1 specifically includes: S101: Acquire test data of a target impact wheel, and divide the target impact wheel into a root bucket high stress area and a root bucket low stress area according to the test data; S102: Establishing an overall model of a target impact runner, and determining a root bucket model of the target impact runner based on a root bucket high stress area and a root bucket low stress area of ​​the target impact runner.

4. The method for manufacturing a low stress bucket at the root of an impact wheel according to claim 3, wherein: The test data include stress distribution test data and process accessibility test data of the target impact wheel.

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