Post-forging heat treatment method and auxiliary tool for fountain forge piece

Abstract

The invention provides a post-forging heat treatment method and an auxiliary tool for a fountain forge piece, and relates to the technical field of heat treatment of steel. During normalizing treatment of an intermediate sample of the fountain forge piece formed through forging, when relevant process steps of transformation from an austenite structure to a martensite structure exist, the normalizing process is carried out; a middle sample of the water bucket forge piece is installed in the auxiliary tool, the bottoms of the two bucket side walls of the sample are clamped in the corresponding constraint notches, the inner walls of the left side and the right side of the upper ring are attached to the bucket side walls, and the auxiliary tool can play a role in restraining the sample from expanding in the process steps; therefore, external expansion and sagging of the bucket side wall of the middle sample of the water bucket forge piece can be inhibited. In the post-forging heat treatment process, external expansion and sagging of the bucket side wall of the middle sample of the water bucket forge piece formed through forging can be restrained through the method, and it is guaranteed that the water bucket forge piece has the fine grain size.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment of steel, and in particular to a post-forging heat treatment method and auxiliary tool for a bucket forging. Background Art

[0002] In an impulse turbine unit, the runner body usually includes a hub and buckets. The hub is the central part connecting the runner and the axle. Multiple buckets are installed on the outer circle of the hub to receive the impact force of the water flow, convert the kinetic energy of the water flow into mechanical energy, and drive the hub to rotate. As the capacity of the unit continues to increase, the requirements for the strength and toughness of the runner body become more and more stringent. The runner body is usually welded by the hub forging and the bucket forging.

[0003] Previously, smaller bucket forgings could be forged into a pancake shape together with the runner forgings, and then processed into buckets after heat treatment. However, larger bucket forgings, such as bucket forgings used for 500-700MW runner forgings, cannot be produced by forging together with the runner and then processing into buckets due to the tonnage of the forgings and the resistance of the materials. The bucket forgings can only be forged or cast separately. However, the density of cast bucket materials is poor, and the ability to withstand huge erosion when used in harsh environments is insufficient. Bucket forgings can overcome the disadvantages of bucket castings by forging. In order to achieve near-net-shape forging of bucket forgings, the structure and size of the forged bucket forging intermediate sample are basically consistent with those of the bucket forging. Specifically, Figure 1-3 As shown, the middle sample of the water bucket forging is a symmetrical structure, including a ridge 11 protruding upward in the middle part and the bucket side walls 12 symmetrically on the left and right sides of the ridge 11, and the lower side of the ridge 11 has a groove 13 corresponding to the ridge 11; wherein, the front and rear ends of the middle sample 1 of the water bucket forging are also provided with a front end notch 14 and a rear end notch 15 respectively, and the left and right bucket side walls 12 are separated, and the front end of the bucket side wall 12 forms a tip. In order to improve the water flow effect of the water bucket forging, each bucket side wall 12 has a certain longitudinal curvature in the longitudinal direction. The forged water bucket forging middle sample 1 needs to be heat treated after forging. During the heat treatment process, the bucket side wall 12 of the middle sample 1 of the water bucket forging will have serious outward expansion and sagging, resulting in a large deformation of the water bucket forging after heat treatment, making it difficult to achieve the near net shape forging of the water bucket forging. In addition, the material of the water bucket forging is 04Cr13Ni5Mo steel. During the production process, it is also necessary to ensure that the water bucket forging has a finer grain size. Summary of the invention

[0004] The problem solved by the present invention is at least one of the following problems: how to suppress the outward expansion and sagging of the bucket side wall of the intermediate sample of the forged water bucket forging during the post-forging heat treatment process; how to ensure that the water bucket forging made of 04Cr13Ni5Mo steel has a finer grain size.

[0005] In order to solve the above problems, the present invention provides an auxiliary tool for suppressing the deformation of the intermediate sample of the forged bucket forging during the post-forging heat treatment process; the intermediate sample of the bucket forging comprises a ridge protruding upward in the middle of the horizontal direction and bucket side walls symmetrically arranged on the left and right sides of the ridge, and the lower side of the ridge is recessed upward to form a groove corresponding to the ridge; a front end notch concave backward is formed in the middle of the front end of the intermediate sample of the bucket forging, and a rear end notch concave forward is formed in the middle of the rear end of the intermediate sample of the bucket forging;

[0006] The auxiliary tool includes an upper ring, a lower ring, an intermediate support column, and two support frames. The upper ring and the lower ring are arranged opposite to each other in the upper and lower directions. The lower end surface of the upper ring and the upper end surface of the lower ring are connected by multiple intermediate support columns to form a cylindrical support structure; the two support frames are arranged inside the cylindrical support structure in a left-right symmetrical manner, and the support frame includes a vertical panel. A downwardly concave binding notch is formed in the middle area of ​​the upper end of the vertical panel, and the binding notch is used to clamp the bottom of the bucket side wall; the inner wall shapes on the left and right sides of the upper ring match the longitudinal curvature of the bucket side wall.

[0007] Compared with the prior art, when normalizing the intermediate sample of the forged water bucket forging, when performing the relevant process steps involving the transformation of the austenite structure into the martensite structure, the intermediate sample of the water bucket forging is installed in the auxiliary tool provided by the present invention, so that the bottoms of the two bucket side walls of the sample are stuck in the corresponding restraining notches, and the inner walls on the left and right sides of the upper ring are fitted with the bucket side walls. The auxiliary tool can play a role in suppressing the expansion of the sample in the above process steps, thereby suppressing the outward expansion and sagging of the bucket side walls of the intermediate sample of the water bucket forging.

[0008] Optionally, the support frame is fixed on the inner wall of the lower ring.

[0009] Optionally, the plurality of intermediate support columns are evenly distributed along the circumference of the cylindrical support structure.

[0010] The present invention also provides a post-forging heat treatment method for a bucket forging, based on the auxiliary tool as described above, comprising:

[0011] Step S1, normalizing treatment: installing the intermediate sample of the bucket forging obtained by forging in the auxiliary tool, keeping the temperature at 500-540°C for 4-6 hours, cooling the temperature to 100-160°C at a preset cooling rate, keeping the temperature for 4-6 hours, heating the temperature to 500-550°C at a first preset heating rate, taking the obtained sample out of the auxiliary tool, heating the temperature to 960-1020°C at a second preset heating rate, keeping the temperature for 8-12 hours, installing the obtained sample in the auxiliary tool, and air cooling the temperature to 100-160°C;

[0012] Step S2, taking the sample obtained after the normalizing treatment out of the auxiliary tool and performing a tempering treatment.

[0013] Compared with the prior art, in the present invention, the intermediate sample of the bucket forging obtained by forging is installed in the auxiliary tool, and then the intermediate sample of the bucket forging is kept at 500-540°C for 4-6 hours to make the temperature inside and outside the sample consistent, thereby reducing the deformation of the sample caused by thermal stress, and then the sample is cooled to 100-160°C and kept for 4-6 hours. During this process, the austenite structure will transform into the martensite structure. Since the sample is installed in the auxiliary tool at this time, the auxiliary tool can play a role in inhibiting the expansion of the sample, thereby inhibiting the bucket forging. The side wall of the bucket of the middle sample of the forging expands and droops; then the sample is heated to 960-1020℃, and the sample is kept at this temperature for a short time (8-12h) to avoid the grain coarsening of the forging due to long-term heat preservation at a high temperature, and then the sample is air-cooled to 100-160℃. During the process of air-cooling the sample from 960-1020℃ to 100-160℃, the austenite structure will also transform into the martensite structure. Similarly, since the sample is installed in the auxiliary tool at this time, the auxiliary tool can play a role in suppressing the expansion of the sample. In summary, during the post-forging heat treatment process, the method of the present invention can suppress the expansion and droop of the side wall of the bucket of the middle sample of the forged bucket forging, and ensure that the bucket forging has a finer grain size.

[0014] Optionally, in step S1, the preset cooling rate is below 10°C / h.

[0015] Optionally, in step S1, the first preset heating rate is 30-40°C / h.

[0016] Optionally, in step S1, the second preset heating rate is 50-80°C / h.

[0017] Optionally, in step S2, after taking out the sample obtained after normalizing treatment from the auxiliary tool, tempering treatment is performed, including: after taking out the sample obtained after normalizing treatment from the auxiliary tool, keeping it warm at 100-160°C for 4-6 hours, heating it to 560-610°C at a third preset heating rate, keeping it warm for 10-15 hours, cooling it in the furnace to 190-200°C, and cooling it out of the furnace.

[0018] Optionally, in step S2, the third preset heating rate is 30-40°C / h.

[0019] Optionally, the material of the intermediate sample of the water bucket forging is 04Cr13Ni5Mo steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a schematic diagram of the three-dimensional structure of the intermediate sample of the bucket forging in the embodiment of the present invention;

[0021] Figure 2 It is a front view of the intermediate sample of the bucket forging in the embodiment of the present invention;

[0022] Figure 3 A top view of an intermediate sample of a bucket forging in an embodiment of the present invention;

[0023] Figure 4 It is a structural schematic diagram of an auxiliary tool in an embodiment of the present invention;

[0024] Figure 5 It is a structural schematic diagram of the embodiment of the present invention when the intermediate sample of the bucket forging is installed in the auxiliary tool;

[0025] Figure 6 This is a front view of the intermediate sample of the water bucket forging when it is installed in the auxiliary tool in an embodiment of the present invention.

[0026] Description of reference numerals:

[0027] 1. Middle sample of bucket forging; 11. Ridge; 12. Bucket side wall; 13. Groove; 14. Front notch; 15. Rear notch; 2. Upper ring; 3. Lower ring; 4. Middle support column; 5. Support frame; 51. Vertical panel; 52. Constraint notch; 53. Bottom column. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0030] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0031] It should be noted that the X-axis in the accompanying drawings represents the longitudinal direction, that is, the front-to-back direction, and the positive direction of the X-axis represents the front, and the negative direction of the X-axis represents the back; the Y-axis in the accompanying drawings represents the transverse direction, that is, the left-to-right direction, and the positive direction of the Y-axis represents the right, and the negative direction of the Y-axis represents the left; the Z-axis in the accompanying drawings represents the vertical direction, that is, the up-and-down direction, and the positive direction of the Z-axis represents the top, and the negative direction of the Z-axis represents the bottom.

[0032] The material of the water bucket forging is 04Cr13Ni5Mo steel. The intermediate sample of the forged water bucket forging needs to be heat treated after forging. The post-forging heat treatment process generally includes normalizing and tempering. During the normalizing process, the austenite structure in the sample will be transformed into martensite structure. The transformation of austenite into martensite will cause a large volume expansion of the sample, resulting in serious outward expansion and sagging of the bucket side wall of the intermediate sample of the water bucket forging, causing a large deformation of the water bucket forging after heat treatment, making it difficult to achieve near-net-shape forging of the water bucket forging.

[0033] In view of the problems existing in the above-mentioned related technologies, this embodiment provides an auxiliary tool for suppressing the deformation of the intermediate sample 1 of the forged bucket forging during the post-forging heat treatment process; Figure 1-3 As shown, the water bucket forging intermediate sample 1 comprises a ridge 11 protruding upward in the middle of the horizontal direction and bucket side walls 12 symmetrically arranged on the left and right sides of the ridge 11, and the lower side of the ridge 11 is recessed upward to form a groove 13 corresponding to the ridge 11; a front end notch 14 concave backward is formed in the middle of the front end of the water bucket forging intermediate sample 1, and a rear end notch 15 concave forward is formed in the middle of the rear end of the water bucket forging intermediate sample 1;

[0034] like Figure 4As shown, the auxiliary tool includes an upper ring 2, a lower ring 3, an intermediate support column 4, and two support frames 5. The upper ring 2 and the lower ring 3 are arranged opposite to each other in the upper and lower directions. The lower end surface of the upper ring 2 and the upper end surface of the lower ring 3 are connected by multiple intermediate support columns 4, thereby forming a cylindrical support structure; the two support frames 5 are arranged inside the cylindrical support structure in a left-right symmetrical manner, and the support frame 5 includes a vertical panel 51. The middle area of ​​the upper end of the vertical panel 51 forms a downwardly concave binding notch 52, and the binding notch 52 is used to clamp the bottom of the bucket side wall 12; the inner wall shapes on the left and right sides of the upper ring 2 match the longitudinal curvature of the bucket side wall 12.

[0035] When used, when normalizing the intermediate sample 1 of the forged bucket forging, when performing the relevant process steps of the transformation from austenite structure to martensite structure, such as Figure 5 and Figure 6 As shown, the intermediate sample 1 of the water bucket forging is installed in the auxiliary tool provided in the embodiment of the present invention, so that the bottoms of the two bucket side walls 12 of the sample are stuck in the corresponding binding notches 52, and the inner walls on the left and right sides of the upper ring 2 are fitted with the bucket side walls 12. The auxiliary tool can play a role in suppressing the expansion of the sample in the above-mentioned process steps, thereby suppressing the bucket side walls 12 of the intermediate sample 1 of the water bucket forging from expanding outward and sagging.

[0036] In some embodiments of the present invention, Figure 4 As shown, the support frame 5 is fixed on the inner wall of the lower ring 3. Specifically, the support frame 5 includes a bottom column 53 and a vertical panel 51, both ends of the bottom column 53 in the length direction are respectively connected to the inner wall of the lower ring 3, and the vertical panel 51 is fixed on the upper end surface of the bottom column 53.

[0037] In some embodiments of the present invention, Figure 4 As shown, the plurality of intermediate support columns 4 are evenly distributed along the circumference of the cylindrical support structure. Specifically, six intermediate support columns 4 are evenly distributed along the circumference of the cylindrical support structure.

[0038] The embodiment of the present invention further provides a post-forging heat treatment method for a bucket forging, based on the auxiliary tool as described above, comprising:

[0039] Step S1, normalizing treatment: Figure 5 and Figure 6As shown, the intermediate sample of the bucket forging obtained by forging is installed in the auxiliary tool, kept at 500-540°C for 4-6h, cooled to 100-160°C at a preset cooling rate, kept for 4-6h, heated to 500-550°C at a first preset heating rate, the obtained sample is taken out of the auxiliary tool, and then heated to 960-1020°C at a second preset heating rate, kept for 8-12h, the obtained sample is installed in the auxiliary tool, and air-cooled to 100-160°C;

[0040] Step S2, taking the sample obtained after the normalizing treatment out of the auxiliary tool and performing a tempering treatment.

[0041] In the embodiment of the present invention, Figure 5 and Figure 6 As shown, the intermediate sample of the water bucket forging obtained by forging is installed in the auxiliary tool, and then the intermediate sample of the water bucket forging is kept at 500-540°C for 4-6 hours to make the temperature inside and outside the sample consistent, thereby reducing the deformation of the sample caused by thermal stress, and then the sample is cooled to 100-160°C and kept for 4-6 hours. During this process, the austenite structure will transform into the martensite structure. Since the sample is installed in the auxiliary tool at this time, the auxiliary tool can play a role in suppressing the expansion of the sample, thereby suppressing the deformation of the intermediate sample of the water bucket forging. The side walls of the bucket expand outward and sag; then the sample is heated to 960-1020℃, and then the sample is kept at this temperature for a short time (8-12h), which can avoid the coarsening of the forging grains due to long-term heat preservation at a high temperature, and then the sample is air-cooled to 100-160℃. During the process of air-cooling the sample from 960-1020℃ to 100-160℃, the austenite structure will also transform into the martensite structure. Similarly, since the sample is installed in the auxiliary tool at this time, the auxiliary tool can play a role in suppressing the expansion of the sample. In summary, during the post-forging heat treatment process, the method of the embodiment of the present invention can suppress the expansion and sagging of the side walls of the bucket of the intermediate sample of the forged bucket forging, and ensure that the bucket forging has a finer grain size.

[0042] In some embodiments of the present invention, in step S1, the preset cooling rate is below 10°C / h. In this embodiment, due to the slow cooling rate, the austenite structure in the inner and outer regions of the sample can be transformed into the martensite structure at the same time, thereby reducing the tissue stress and further reducing the deformation of the sample.

[0043] In some embodiments of the present invention, in step S1, the first preset heating rate is 30-40°C / h. In this embodiment, due to the slow heating rate (30-40°C / h), the martensite recovers slowly, which can effectively reduce the thermal stress and tissue stress of the sample, and further reduce the deformation of the sample.

[0044] In some embodiments of the present invention, in step S1, the second preset heating rate is 50-80°C / h. In this embodiment, since the heating rate is relatively fast (50-80°C / h), the driving force for nucleation of the material can be effectively increased, promoting the nucleation of grains, thereby effectively refining the grains.

[0045] In some embodiments of the present invention, in step S2, after taking out the sample obtained after normalizing treatment from the auxiliary tool, tempering treatment is performed, including: after taking out the sample obtained after normalizing treatment from the auxiliary tool, keeping it warm at 100-160°C for 4-6 hours, heating it to 560-610°C at a third preset heating rate, keeping it warm for 10-15 hours, cooling it in the furnace to 190-200°C, and cooling it out of the furnace.

[0046] In some embodiments of the present invention, in step S2, the third preset heating rate is 30-40°C / h.

[0047] In some embodiments of the present invention, the material of the intermediate sample of the bucket forging is 04Cr13Ni5Mo steel, and the components include: C: 0.01-0.04%, Si: 0-0.6%, Mn: 0.50-1.00%, Cr: 12.0-13.5%, Mo: 0.40-0.80%, Ni: 4.5-6.0%, V: 0-0.07%, Cu: 0-0.50%, W: 0-0.10%, S: 0-0.008%, P: 0-0.020%, and the remainder is Fe and unavoidable impurities; wherein, the sum of the mass fractions of V, Cu and W is 0-0.50%.

[0048] The present invention is further described below in conjunction with specific embodiments.

[0049] Example 1

[0050] A1. Normalizing treatment: The intermediate sample of the bucket forging obtained by forging is installed in the auxiliary tool provided by the embodiment of the present invention, kept at 520°C for 5 hours, cooled to 130°C at a preset cooling rate, kept at this temperature for 5 hours, heated to 525°C at a first preset heating rate, the obtained sample is taken out of the auxiliary tool, and then heated to 990°C at a second preset heating rate, kept at this temperature for 10 hours, the obtained sample is installed in the auxiliary tool, and air-cooled to 130°C; wherein the preset cooling rate is 5°C / h, the The first preset heating rate is 35°C / h, and the second preset heating rate is 65°C / h; in terms of weight percentage, the components of the intermediate sample of the bucket forging include: C: 0.02%, Si: 0.3%, Mn: 0.70%, Cr: 12.5%, Mo: 0.60%, Ni: 5.0%, V: 0.03%, Cu: 0.20%, W: 0.05%, S: 0.004%, P: 0.010%, and the balance is Fe and unavoidable impurities.

[0051] A2. Tempering treatment: After taking the sample obtained after normalizing treatment out of the auxiliary tool, keep it at 130°C for 5 hours, heat it to 585°C at a third preset heating rate, keep it for 13 hours, cool it to 195°C in the furnace, cool it out of the furnace, and obtain the final bucket forging sample; wherein, the third preset heating rate is 35°C / h.

[0052] After testing, the side wall of the bucket of the final bucket forging sample prepared in Example 1 did not show outward expansion and sagging.

[0053] Example 2

[0054] A1. Normalizing treatment: The intermediate sample of the bucket forging obtained by forging is installed in the auxiliary tool provided by the embodiment of the present invention, kept at 540°C for 4 hours, cooled to 160°C at a preset cooling rate, kept at this temperature for 4 hours, heated to 550°C at a first preset heating rate, the obtained sample is taken out of the auxiliary tool, heated to 1020°C at a second preset heating rate, kept at this temperature for 8 hours, the obtained sample is installed in the auxiliary tool, and air-cooled to 130°C; wherein the preset cooling rate is 5°C / h, the The first preset heating rate is 40°C / h, and the second preset heating rate is 80°C / h; in terms of weight percentage, the components of the intermediate sample of the bucket forging include: C: 0.02%, Si: 0.3%, Mn: 0.70%, Cr: 12.5%, Mo: 0.60%, Ni: 5.0%, V: 0.03%, Cu: 0.20%, W: 0.05%, S: 0.004%, P: 0.010%, and the balance is Fe and unavoidable impurities.

[0055] A2. Tempering treatment: After taking the sample obtained after normalizing treatment out of the auxiliary tool, keep it at 160°C for 4 hours, heat it to 610°C at a third preset heating rate, keep it for 10 hours, cool it to 195°C in the furnace, cool it out of the furnace, and obtain the final bucket forging sample; wherein, the third preset heating rate is 40°C / h.

[0056] After testing, the side wall of the bucket of the final water bucket forging sample prepared in Example 2 did not show any outward expansion or sagging.

[0057] Example 3

[0058] A1. Normalizing treatment: The intermediate sample of the bucket forging obtained by forging is installed in the auxiliary tool provided by the embodiment of the present invention, kept at 500°C for 6 hours, cooled to 100°C at a preset cooling rate, kept at this temperature for 6 hours, heated to 500°C at a first preset heating rate, the obtained sample is taken out of the auxiliary tool, and then heated to 960°C at a second preset heating rate, kept at this temperature for 12 hours, the obtained sample is installed in the auxiliary tool, and air-cooled to 130°C; wherein the preset cooling rate is 5°C / h, the The first preset heating rate is 30°C / h, and the second preset heating rate is 50°C / h; in terms of weight percentage, the components of the intermediate sample of the bucket forging include: C: 0.02%, Si: 0.3%, Mn: 0.70%, Cr: 12.5%, Mo: 0.60%, Ni: 5.0%, V: 0.03%, Cu: 0.20%, W: 0.05%, S: 0.004%, P: 0.010%, and the balance is Fe and unavoidable impurities.

[0059] A2. Tempering treatment: After taking the sample obtained after normalizing treatment out of the auxiliary tool, keep it at 100°C for 6 hours, heat it to 560°C at a third preset heating rate, keep it for 15 hours, cool it to 195°C in the furnace, cool it out of the furnace, and obtain the final bucket forging sample; wherein, the third preset heating rate is 30°C / h.

[0060] After testing, the side wall of the bucket of the final water bucket forging sample prepared in Example 3 did not show outward expansion and sagging.

[0061] Comparative Example (the auxiliary tool provided by the embodiment of the present invention is not used during the normalizing process)

[0062] The difference from Example 1 is that step A1 is: keeping the intermediate sample of the water bucket forging obtained by forging at 540°C for 4h, cooling it to 160°C at a preset cooling rate, keeping it for 4h, heating it to 550°C at a first preset heating rate, and then heating it to 1020°C at a second preset heating rate, keeping it for 8h, and air cooling it to 130°C; wherein the preset cooling rate is 5°C / h, the first preset heating rate is 40°C / h, and the second preset heating rate is 80°C / h; in terms of weight percentage, the components of the intermediate sample of the water bucket forging include: C: 0.02%, Si: 0.3%, Mn: 0.70%, Cr: 12.5%, Mo: 0.60%, Ni: 5.0%, V: 0.03%, Cu: 0.20%, W: 0.05%, S: 0.004%, P: 0.010%, and the remainder is Fe and unavoidable impurities.

[0063] After testing, it was found that the side wall of the bucket of the final water bucket forging sample prepared in the comparative example showed serious outward expansion and sagging.

[0064] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An auxiliary tool, characterized in that: Used to suppress the deformation of a forged bucket forging intermediate sample (1) during a post-forging heat treatment process; the bucket forging intermediate sample (1) comprises a ridge (11) protruding upward in the middle of the horizontal direction and bucket side walls (12) symmetrically arranged on the left and right sides of the ridge (11); the lower side of the ridge (11) is recessed upward to form a groove (13) corresponding to the ridge (11); a front end notch (14) concave backward is formed in the middle of the front end of the bucket forging intermediate sample (1), and a rear end notch (15) concave forward is formed in the middle of the rear end of the bucket forging intermediate sample (1); The auxiliary tool comprises an upper ring (2), a lower ring (3), an intermediate support column (4), and two support frames (5); the upper ring (2) and the lower ring (3) are arranged opposite to each other in the upper and lower directions; the lower end surface of the upper ring (2) and the upper end surface of the lower ring (3) are connected via a plurality of intermediate support columns (4), thereby forming a cylindrical support structure; the two support frames (5) are arranged inside the cylindrical support structure in a left-right symmetrical manner; the support frame (5) comprises a vertical panel (51); a downwardly concave binding notch (52) is formed in the middle area of ​​the upper end of the vertical panel (51); the binding notch (52) is used to clamp the bottom of the bucket side wall (12); the inner wall shapes on the left and right sides of the upper ring (2) match the longitudinal curvature of the bucket side wall (12).

2. The assistive device according to claim 1, characterized in that: The support frame (5) is fixed on the inner wall of the lower ring (3).

3. The assistive device according to claim 1, characterized in that: The plurality of intermediate support columns (4) are evenly distributed along the circumference of the cylindrical support structure.

4. A post-forging heat treatment method for a bucket forging, characterized in that: Based on the assistive device according to any one of claims 1 to 3, comprising: Step S1, normalizing treatment: installing the intermediate sample of the bucket forging obtained by forging in the auxiliary tool, keeping the temperature at 500-540°C for 4-6 hours, cooling the temperature to 100-160°C at a preset cooling rate, keeping the temperature for 4-6 hours, heating the temperature to 500-550°C at a first preset heating rate, taking the obtained sample out of the auxiliary tool, heating the temperature to 960-1020°C at a second preset heating rate, keeping the temperature for 8-12 hours, installing the obtained sample in the auxiliary tool, and air cooling the temperature to 100-160°C; Step S2, taking the sample obtained after the normalizing treatment out of the auxiliary tool and performing a tempering treatment.

5. The post-forging heat treatment method of a bucket forging according to claim 4, characterized in that: In the step S1, the preset cooling rate is below 10°C / h.

6. The post-forging heat treatment method of a bucket forging according to claim 4, characterized in that: In the step S1, the first preset heating rate is 30-40°C / h.

7. The post-forging heat treatment method of a bucket forging according to claim 4, characterized in that: In the step S1, the second preset heating rate is 50-80°C / h.

8. The post-forging heat treatment method of a bucket forging according to claim 4, characterized in that: In the step S2, after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, a tempering treatment is performed, including: after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, it is kept warm at 100-160°C for 4-6 hours, heated to 560-610°C at a third preset heating rate, kept warm for 10-15 hours, cooled to 190-200°C in the furnace, and cooled out of the furnace.

9. The post-forging heat treatment method of a bucket forging according to claim 8, characterized in that: In the step S2, the third preset heating rate is 30-40°C / h.

10. The post-forging heat treatment method of a bucket forging according to claim 4, characterized in that: The material of the intermediate sample of the water bucket forging is 04Cr13Ni5Mo steel.

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