A post-forging heat treatment method and auxiliary tool for a water bucket forging

Abstract

The application provides a post-forging heat treatment method and auxiliary tool for a water bucket forging, and relates to the technical field of steel heat treatment. In the application, when the intermediate sample of the water bucket forging formed by forging is subjected to normalizing treatment, the intermediate sample of the water bucket forging is installed in the auxiliary tool provided by the application when the related process step of the transformation of austenite structure into martensite structure is performed, the bottom of the two bucket side walls of the sample is clamped in the corresponding restraint notches, and the inner walls on the left and right sides of the upper ring are attached to the bucket side walls. The auxiliary tool can inhibit the expansion of the sample in the above process step, so that the outward expansion and drooping of the bucket side wall of the intermediate sample of the water bucket forging can be inhibited. In the post-forging heat treatment process, the method provided by the application can inhibit the outward expansion and drooping of the bucket side wall of the intermediate sample of the water bucket forging formed by forging, and ensure that the water bucket forging has a fine grain size.

Description

TECHNICAL FIELD

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

[0002] In a Pelton turbine unit, the runner body usually includes a hub and a water bucket, the hub is a central part connecting the runner and the wheel shaft, and a plurality of water buckets are installed on the outer circle of the hub for receiving the impact force of water flow, converting the kinetic energy of water flow into mechanical energy, and pushing the hub to rotate. With the continuous increase of the capacity of the unit, the strength and toughness indicators of the runner body are becoming more and more stringent, and the runner body is usually welded from a hub forging and a water bucket forging.

[0003] Previously, for smaller water bucket forgings, they can be forged into a pie shape together with the runner forging, and then processed into the form of a water bucket after heat treatment, but for larger water bucket forgings, such as water bucket forgings for 500-700MW level runner forgings, due to the influence of tonnage and material resistance of the forging, they cannot be produced in the form of being forged together with the runner and then processed into a water bucket, and can only be forged or cast separately, but the material density of the cast water bucket is poor, and its ability to withstand large erosion in harsh environments is not enough. The water bucket forging can overcome the drawbacks of the water bucket casting. In order to realize the near-net-shape forging of the water bucket forging, the structure and size of the forged water bucket forging intermediate sample are basically the same as those of the water bucket forging, specifically, as shown in Figures 1-3 The water bucket forging intermediate sample is a symmetrical structure, including a middle part upwardly protruding ridge 11 and symmetrical bucket side walls 12 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 water bucket forging intermediate sample 1 are also respectively provided with a front end notch 14 and a rear end notch 15, which separate the left and right bucket side walls 12 and make the front end of the bucket side wall 12 form a sharp end, and 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 intermediate sample 1 needs to be heat treated after forging, and the bucket side wall 12 of the water bucket forging intermediate sample 1 will be severely expanded and sagged during the heat treatment after forging, resulting in large deformation of the water bucket forging after heat treatment, and it is difficult to realize the near-net-shape forging of the water bucket forging. In addition, the material of the water bucket forging is 04Cr13Ni5Mo steel, and it is also necessary to ensure that the water bucket forging has a fine grain size during production. SUMMARY

[0004] The problems solved by the present application are at least one of the following problems: how to suppress the expansion and sagging of the bucket side wall of the forged water bucket forging intermediate sample during the heat treatment after forging; how to ensure that the water bucket forging with a material of 04Cr13Ni5Mo steel has a fine grain size.

[0005] To solve the above problems, the present application provides an auxiliary tool for restraining the deformation of a water bucket intermediate sample during post-forging heat treatment, wherein the water bucket intermediate sample comprises a ridge part protruding upward in the middle of the transverse direction and bucket side walls symmetrically arranged on the left and right sides of the ridge part, the lower side of the ridge part is concave upward to form a groove corresponding to the ridge part, the middle of the front end of the water bucket intermediate sample is formed with a rearward concave front end notch, and the middle of the rear end of the water bucket intermediate sample is formed with a forward concave rear end notch.

[0006] The auxiliary tool comprises an upper ring, a lower ring, intermediate support columns, and two support frames, the upper ring and the lower ring are arranged oppositely, the lower end surface of the upper ring and the upper end surface of the lower ring are connected by the intermediate support columns to form a cylindrical support structure, the two support frames are arranged symmetrically in the left and right directions inside the cylindrical support structure, the support frame comprises a vertical panel, the middle area of the upper end of the vertical panel is formed with a downward concave restraint notch for clamping the bottom of the bucket side wall, and the inner walls on the left and right sides of the upper ring are matched with the longitudinal curvature of the bucket side wall.

[0007] Compared with the prior art, when the water bucket intermediate sample is subjected to normalizing treatment, the water bucket intermediate sample is installed in the auxiliary tool provided by the present application when the relevant process step of austenite to martensite transformation is performed, the bottom of the two bucket side walls of the sample is clamped in the corresponding restraint notch, the inner walls on the left and right sides of the upper ring are matched with the bucket side wall, and the auxiliary tool can restrain the expansion of the sample in the above process step, thereby restraining the outward expansion and sagging of the bucket side wall of the water bucket intermediate sample.

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

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

[0010] The present application also provides a post-forging heat treatment method for a water bucket intermediate sample, which is based on the auxiliary tool described above and comprises the following steps:

[0011] Step S1, normalizing treatment: the water bucket intermediate sample obtained by forging is installed in the auxiliary tool, is kept at 500-540℃ for 4-6h, is cooled at a preset cooling rate to 100-160℃, is kept at 100-160℃ for 4-6h, is heated at a first preset heating rate to 500-550℃, is taken out of the auxiliary tool, is heated at a second preset heating rate to 960-1020℃, is kept at 960-1020℃ for 8-12h, and is installed in the auxiliary tool and is air-cooled to 100-160℃.

[0012] Step S2, after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, tempering treatment is performed.

[0013] Compared with the prior art, in the present application, the water bucket forged intermediate sample obtained by forging is installed in the auxiliary tool, then the water bucket forged intermediate sample is kept at 500-540℃ for 4-6h to make the temperature inside and outside the sample consistent, thereby reducing the sample deformation caused by thermal stress, then the sample is cooled to 100-160℃ and kept for 4-6h, during which the austenite organization is transformed into martensite organization, and 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 outward expansion and drooping of the bucket side wall of the water bucket forged intermediate sample; then the sample is heated to 960-1020℃, and the sample is kept at this temperature for a short time (8-12h), which can avoid the grain coarsening of the forged product caused by long-time keeping at a high temperature, then the sample is air-cooled to 100-160℃, and during the process of air-cooling the sample from 960-1020℃ to 100-160℃, the austenite organization is also transformed into martensite organization, and 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. In summary, during the post-forging heat treatment, the method of the present application can inhibit the outward expansion and drooping of the bucket side wall of the water bucket forged intermediate sample formed by forging, and ensure that the water bucket forged product has a fine grain size.

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

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

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

[0017] Optionally, in the step S2, after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, tempering treatment is performed, which comprises: after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, keeping at 100-160℃ for 4-6h, heating to 560-610℃ at a third preset heating rate, keeping for 10-15h, furnace cooling to 190-200℃, and furnace cooling.

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

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

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

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

[0022] Figure 3 It is a top view of the water bucket forging intermediate sample in the embodiment of the present application;

[0023] Figure 4 It is a structure schematic view of the auxiliary tool in the embodiment of the present application;

[0024] Figure 5 It is a structure schematic view when the water bucket forging intermediate sample is installed in the auxiliary tool in the embodiment of the present application;

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

[0026] Explanation of reference signs:

[0027] 1, water bucket forging intermediate sample; 11, ridge; 12, bucket side wall; 13, groove; 14, front end notch; 15, rear end notch; 2, upper ring; 3, lower ring; 4, intermediate support column; 5, support frame; 51, vertical panel; 52, restraint notch; 53, bottom column. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purpose, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below in combination with the drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be realized in various forms, and should not be interpreted as being limited to the embodiments described herein, on the contrary, these embodiments are provided in order to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes, and are not intended to limit the scope of protection of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application in the specification are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application;

[0030] The term "include" and variations thereof, as used in this document, mean the same as "comprise" or "comprises." The term "based on" means "based, at least in part, on." The term "one embodiment" means "at least one embodiment." The term "another embodiment" means "at least one additional embodiment." The term "some embodiments" means "at least some embodiments." The term "optional" means "optional in at least some embodiments." Related terms such as "one embodiment," "an embodiment," "some embodiments," and "another embodiment" refer to "one selected embodiment," "an

[0031] It should be noted that the X-axis in the drawings represents the longitudinal direction, that is, the front-rear direction, and the positive direction of the X-axis represents the front, and the negative direction of the X-axis represents the rear; the Y-axis in the drawings represents the lateral direction, that is, the left-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 drawings represents the vertical direction, that is, the up-down direction, and the positive direction of the Z-axis represents the up, and the negative direction of the Z-axis represents the down.

[0032] The material of the water bucket forging is 04Cr13Ni5Mo steel. The intermediate sample of the water bucket forging formed by forging needs to be subjected to post-forging heat treatment. The post-forging heat treatment process generally includes normalizing treatment and tempering treatment. In the normalizing treatment 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 a serious outward expansion and sag of the side wall of the intermediate sample of the water bucket forging, so that the water bucket forging after heat treatment is deformed greatly, and it is difficult to realize near-net forming forging of the water bucket forging.

[0033] To solve the problems in the related art, the embodiment provides an auxiliary tool for inhibiting the deformation of the intermediate sample 1 of the water bucket forging formed by forging during the post-forging heat treatment process. As shown in Figures 1-3 The intermediate sample 1 of the water bucket forging includes a ridge 11 protruding upward in the transverse middle part and 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. The middle part of the front end of the intermediate sample 1 of the water bucket forging is formed with a front end notch 14 recessed inwardly rearward, and the middle part of the rear end of the intermediate sample 1 of the water bucket forging is formed with a rear end notch 15 recessed inwardly forward.

[0034] As shown in Figure 4As shown, the auxiliary tool includes an upper ring 2, a lower ring 3, intermediate support columns 4, and two support frames 5. The upper ring 2 and the lower ring 3 are arranged oppositely, and the lower end surface of the upper ring 2 and the upper end surface of the lower ring 3 are connected by the intermediate support columns 4, thereby forming a cylindrical support structure. The two support frames 5 are arranged symmetrically inside the cylindrical support structure. The support frame 5 includes a vertical panel 51, and the upper end middle area of the vertical panel 51 forms a downwardly recessed restraint notch 52 for clamping the bottom of the bucket side wall 12. The inner walls on the left and right sides of the upper ring 2 match the longitudinal curvature of the bucket side wall 12.

[0035] In use, when the water bucket forging intermediate sample 1 is subjected to normalizing treatment, during the relevant process step in which the austenite structure is transformed into the martensite structure, as shown in Figure 5 and Figure 6 the water bucket forging intermediate sample 1 is installed in the auxiliary tool provided by the embodiment of the present application, and the bottom of the two bucket side walls 12 of the sample is clamped in the corresponding restraint notch 52, and the inner walls on the left and right sides of the upper ring 2 are in contact with the bucket side wall 12. The auxiliary tool can inhibit the expansion of the sample during the above process step, thereby inhibiting the outward expansion and sagging of the bucket side wall 12 of the water bucket forging intermediate sample 1.

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

[0037] In some embodiments of the present application, as shown in Figure 4 the intermediate support columns 4 are uniformly distributed along the circumference of the cylindrical support structure. Specifically, six intermediate support columns 4 are uniformly distributed along the circumference of the cylindrical support structure.

[0038] The embodiment of the present application also provides a post-forging heat treatment method for a water bucket forging, based on the auxiliary tool as described above, including:

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

[0040] After the sample obtained by normalizing is taken out from the auxiliary tool, the sample is subjected to tempering.

[0041] In the embodiment of the present application, as shown in the figure, Figure 5 and Figure 6 As shown in the figure, the water bucket forging intermediate sample obtained by forging is installed in the auxiliary tool, and then, the water bucket forging intermediate sample is kept at 500-540 DEG C for 4-6 h, so that the temperature inside and outside the sample is consistent, thereby reducing the deformation of the sample caused by thermal stress, and then, the sample is cooled to 100-160 DEG C and is kept at 100-160 DEG C for 4-6 h, and in this process, the austenite structure is transformed into the martensite structure, and since the sample is installed in the auxiliary tool at this time, the auxiliary tool can inhibit the expansion of the sample, thereby inhibiting the outward expansion and sagging of the bucket side wall of the water bucket forging intermediate sample; then, the sample is heated to 960-1020 DEG C, and the sample is kept at this temperature for a short time (8-12 h), which can avoid the grain coarsening of the forging caused by long-time keeping at a high temperature, and then, the sample is air-cooled to 100-160 DEG C, and in the process of air-cooling the sample from 960-1020 DEG C to 100-160 DEG C, the austenite structure is also transformed into the martensite structure, and since the sample is installed in the auxiliary tool at this time, the auxiliary tool can inhibit the expansion of the sample. In summary, in the post-forging heat treatment process, the method of the embodiment of the present application can inhibit the outward expansion and sagging of the bucket side wall of the water bucket forging intermediate sample formed by forging, and can ensure that the water bucket forging has a fine grain size.

[0042] In some embodiments of the present application, in the step S1, the preset cooling rate is below 10 DEG C / h. In this embodiment, since the cooling rate is slow, the transformation of the austenite structure into the martensite structure can occur in the internal and external regions of the sample at the same time, thereby reducing the structure stress and further reducing the deformation of the sample.

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

[0044] In some embodiments of the present application, in the step S1, the second preset heating rate is 50-80℃ / h. In this embodiment, the material nucleation driving force can be effectively increased due to the fast heating rate (50-80℃ / h), so that the grain nucleation is promoted, thereby effectively refining the grains.

[0045] In some embodiments of the present application, in the step S2, after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, the sample is subjected to tempering treatment, which comprises: after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, the sample is heated to 560-610℃ at a third preset heating rate, and then the sample is kept at the temperature for 10-15h, and then the sample is furnace-cooled to 190-200℃, and then the sample is taken out and cooled.

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

[0047] In some embodiments of the present application, the material of the water bucket forging intermediate sample 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 balance is Fe and inevitable impurities; wherein the sum of the mass fractions of V, Cu and W is 0-0.50%.

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

[0049] Embodiment 1

[0050] A1, normalizing treatment: the water bucket forging intermediate sample obtained by forging is installed in the auxiliary tool provided by the embodiment of the present application, and then the sample is kept at 520℃ for 5h, and then the sample is cooled to 130℃ at a preset cooling rate, and then the sample is kept at 130℃ for 5h, and then the sample is heated to 525℃ at a first preset heating rate, and then the sample obtained is taken out from the auxiliary tool, and then the sample is heated to 990℃ at a second preset heating rate, and then the sample is kept at 990℃ for 10h, and then the sample obtained is installed in the auxiliary tool, and then the sample is air-cooled to 130℃; wherein the preset cooling rate is 5℃ / h, the first preset heating rate is 35℃ / h, and the second preset heating rate is 65℃ / h; the components of the water bucket forging intermediate sample include, by weight percentage: 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 inevitable impurities.

[0051] A2, tempering treatment: after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, it is kept at 130℃ for 5h, heated to 585℃ at a third preset heating rate, kept at 585℃ for 13h, furnace cooled to 195℃, and taken out for cooling, to obtain a final water bucket forging sample; wherein the third preset heating rate is 35℃ / h.

[0052] It is detected that the bucket side wall of the final water bucket forging sample prepared in Example 1 does not appear to be outwardly expanded and sagged.

[0053] Example 2

[0054] A1, normalizing treatment: the water bucket forging intermediate sample is installed in the auxiliary tool provided by the embodiment of the application, kept at 540℃ for 4h, cooled to 160℃ at a preset cooling rate, kept at 160℃ for 4h, heated to 550℃ at a first preset heating rate, taken out from the auxiliary tool, heated to 1020℃ at a second preset heating rate, kept at 1020℃ for 8h, installed in the auxiliary tool, and air cooled to 130℃; wherein the preset cooling rate is 5℃ / h, the first preset heating rate is 40℃ / h, and the second preset heating rate is 80℃ / h; the components of the water bucket forging intermediate sample include, by weight percentage: 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 of Fe and inevitable impurities.

[0055] A2, tempering treatment: after the sample obtained after the normalizing treatment is taken out from the auxiliary tool, it is kept at 160℃ for 4h, heated to 610℃ at a third preset heating rate, kept at 610℃ for 10h, furnace cooled to 195℃, and taken out for cooling, to obtain a final water bucket forging sample; wherein the third preset heating rate is 40℃ / h.

[0056] It is detected that the bucket side wall of the final water bucket forging sample prepared in Example 2 does not appear to be outwardly expanded and sagged.

[0057] Example 3

[0058] A1, normalizing treatment: the water bucket forging intermediate sample obtained by forging is installed in the auxiliary tool provided by the embodiment of the application, is kept at 500℃ for 6h, is cooled to 100℃ at a preset cooling rate, is kept at 100℃ for 6h, is heated to 500℃ at a first preset heating rate, is taken out of the auxiliary tool, is heated to 960℃ at a second preset heating rate, is kept at 960℃ for 12h, is installed in the auxiliary tool, and is air-cooled to 130℃; wherein the preset cooling rate is 5℃ / h, the first preset heating rate is 30℃ / h, and the second preset heating rate is 50℃ / h; the components of the water bucket forging intermediate sample include, by weight percentage, 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 of Fe and inevitable impurities.

[0059] A2, tempering treatment: after the sample obtained by the normalizing treatment is taken out of the auxiliary tool, the sample is heated to 560℃ at a third preset heating rate at 100℃ for 6h, is kept at 560℃ for 15h, is furnace-cooled to 195℃, is taken out of the furnace, and is cooled to obtain a final water bucket forging sample; wherein the third preset heating rate is 30℃ / h.

[0060] It is detected that the bucket side wall of the final water bucket forging sample obtained in Example 3 does not appear to be outwardly expanded and sagged.

[0061] Comparative example (without using the auxiliary tool provided by the embodiment of the application in the normalizing process)

[0062] The difference from Example 1 is that step A1 is: the water bucket forging intermediate sample obtained by forging is kept at 540℃ for 4h, is cooled to 160℃ at a preset cooling rate, is kept at 160℃ for 4h, is heated to 550℃ at a first preset heating rate, is heated to 1020℃ at a second preset heating rate, is kept at 1020℃ for 8h, and is air-cooled to 130℃; wherein the preset cooling rate is 5℃ / h, the first preset heating rate is 40℃ / h, and the second preset heating rate is 80℃ / h; the components of the water bucket forging intermediate sample include, by weight percentage, 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 of Fe and inevitable impurities.

[0063] It is detected that the bucket side wall of the final water bucket forging sample obtained in the comparative example appears to be severely outwardly expanded and sagged.

[0064] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the application, and it is intended to include all such changes and modifications as fall within the scope of the application.

Claims

1. An assistive device, comprising: The application relates to a water bucket intermediate sample (1) for restraining deformation of a water bucket intermediate sample in a post-forging heat treatment process, wherein the water bucket intermediate sample (1) comprises a ridge (11) upwardly protruding in the middle of the transverse direction, bucket side walls (12) symmetrically arranged on the left and right sides of the ridge (11), and a groove (13) upwardly recessed on the lower side of the ridge (11) and corresponding to the ridge (11); a front end notch (14) is formed in the middle of the front end of the water bucket intermediate sample (1) and is inwardly recessed towards the rear end; and a rear end notch (15) is formed in the middle of the rear end of the water bucket intermediate sample (1) and is inwardly recessed towards the front end. The auxiliary tool comprises an upper ring (2), a lower ring (3), intermediate support columns (4), and two support frames (5), the upper ring (2) and the lower ring (3) are arranged oppositely, the lower end surface of the upper ring (2) and the upper end surface of the lower ring (3) are connected through the intermediate support columns (4) to form a cylindrical support structure, the two support frames (5) are arranged symmetrically in the inside of the cylindrical support structure, the support frame (5) comprises a vertical panel (51), the middle area of the upper end of the vertical panel (51) is formed with a restraint notch (52) downwardly recessed, the restraint notch (52) is used for clamping the bottom of the bucket side wall (12), and the inner wall of the left and right sides of the upper ring (2) is matched with the longitudinal curvature of the bucket side wall (12).

2. The assistive device of claim 1, wherein, The support frame (5) is fixed on the inner wall of the lower ring (3).

3. The assistive device of claim 1, wherein, The intermediate support columns (4) are uniformly distributed along the circumferential direction of the cylindrical support structure.

4. A method of post-forgmg heat treatment of a water bucket forging, characterized by, The auxiliary tool is based on any one of claims 1-3, comprising: In step S1, normalizing treatment: the water bucket intermediate sample obtained through forging is installed in the auxiliary tool, is kept at 500-540 DEG C for 4-6 h, is cooled at a preset cooling rate to 100-160 DEG C, is heated at a first preset heating rate to 500-550 DEG C, is taken out from the auxiliary tool, is heated at a second preset heating rate to 960-1020 DEG C, is kept for 8-12 h, is installed in the auxiliary tool, and is air-cooled to 100-160 DEG C. In step S2, after the sample obtained through the normalizing treatment is taken out from the auxiliary tool, tempering treatment is carried out.

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

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

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

8. The method for post-forgmg heat treatment of a ladle forging according to claim 4, characterized by In step S2, after the sample obtained through the normalizing treatment is taken out from the auxiliary tool, tempering treatment is carried out, which comprises the following steps: after the sample obtained through the normalizing treatment is taken out from the auxiliary tool, the sample is kept at 100-160 DEG C for 4-6 h, is heated at a third preset heating rate to 560-610 DEG C, is kept for 10-15 h, is furnace-cooled to 190-200 DEG C, and is taken out for cooling.

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

10. The method for post-forgmg heat treatment of a ladle forging according to claim 4, characterized by The material of the water bucket intermediate sample is 04Cr13Ni5Mo steel.

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