Preforming method of high-temperature alloy forge piece
Through two-stage preforming method and solid solution treatment, the problems of inconsistent size and different forming in the process of making traditional high-temperature alloy forgings are solved, and higher molding accuracy and high-temperature performance are achieved.
Patent Information
- Application Number
- CN202411848769.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-03-18
AI Technical Summary
During the process of making traditional high-temperature alloy forgings, the ring blanks are inconsistent in size and large forming differences, resulting in low production efficiency and unstable final product performance.
A two-stage preforming method is adopted, first upsetting through the first membrane, then punching and shaping in the second membrane, combined with solid solution treatment to improve the uniformity and high-temperature performance of the alloy.
It improves the molding accuracy and tissue consistency of the forgings, reduces the load and wear of the mold, extends the service life of the mold, and improves the high temperature strength and oxidation resistance of the forgings.
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Figure CN119634631A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of high-temperature alloy forming, and in particular to a preforming method for high-temperature alloy forgings. Background Art
[0002] High-temperature alloys are a class of metal materials based on iron, nickel, and cobalt that can withstand long-term operation at temperatures exceeding 600°C and under certain stresses. Due to their ability to maintain stable mechanical properties at high temperatures, high-temperature alloys are widely used both domestically and internationally. Different methods of manufacturing can affect the quality of the ring blanks and the performance of the forgings.
[0003] With the development of industrial technology, especially the aviation and aerospace products, the performance requirements of forgings are relatively high, which also means that the size consistency of forging ring blanks is required to ensure the stable performance of the final product. Traditional free forging technology uses upsetting, punching and hole expansion to make blanks: the bar is upset to a certain height using the anvil surface of the press, and the forward and reverse punching or the use of a leaking plate is determined according to the height of the blank. After punching, the punch is used to shape and flatten the end face. The decision of whether to perform forward and reverse punching is made according to the actual situation. After punching, the ring blank is shaped into a full circle. Usually, it is also necessary to decide whether to grind and clean the scratches based on the quality of the punching.
[0004] When making small ring blanks using the traditional forging method, the punching size is small and the hole diameter cannot meet the core shaft size of the ring machine. A hole expansion process is required. At this time, the end face R angle is large, and then a shaping process is performed. When the number of products is large, the forming size and shape of forgings in the same batch vary greatly, reducing production efficiency.
[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention
[0006] In view of the deficiencies of the prior art, the present invention discloses a preforming method for high-temperature alloy forgings.
[0007] The technical solutions adopted in the present invention are as follows:
[0008] A method for preforming a high-temperature alloy forging, comprising the following steps:
[0009] Step S1, blanking:
[0010] Step S2, fetal membrane forging, including step 1 and step 2;
[0011] In the first step, a fetal membrane is designed. The fetal membrane is provided with an inner hole with a diameter gradually decreasing from top to bottom. The forging blank is placed in the fetal membrane for upsetting, and then the forging is returned to the furnace for heat preservation.
[0012] In the second step, a second membrane is designed. The second membrane is provided with an inner hole with a diameter gradually decreasing from top to bottom. The bottom of the inner hole is also provided with a step extending inward. A membrane bottom sheet is placed on the step. The forging is transferred to the second membrane for punching.
[0013] Step S3, pre-rolling;
[0014] Step S4, ring rolling;
[0015] Step S5, solution treatment, the solution temperature of the forging is 1177±14°C, and then cooling.
[0016] Furthermore, the inclination angle of the inner wall of the fetal membrane 1 ranges from 80 to 84 degrees, and the inclination angle of the inner wall of the fetal membrane 2 ranges from 87 to 89 degrees.
[0017] Furthermore, in step 1 of step S2, the furnace heating temperature is 1140±10°C, and the holding time ranges from 115 to 205 minutes.
[0018] Furthermore, in step 1 and step 2 of step S2, the working temperature of fetal membrane 1 and fetal membrane 2 is 250-350°C.
[0019] Furthermore, in step 1 and step 2 of step S2, the final forging temperature of the forging is ≥ 950°C.
[0020] Furthermore, in step 1 and step 2 of step S2, the hammer head presses down at a speed of 20 to 70 mm / s.
[0021] Furthermore, in step S3, the final forging temperature is ≥950°C, and after the deformation is completed, the steel is returned to the furnace and heated for 30 minutes to flatten the end surface.
[0022] Furthermore, in step S4, the final forging temperature is ≥950°C, and after the deformation is completed, the steel is returned to the furnace and heated for 30 minutes to flatten the end surface.
[0023] Furthermore, in step S5, the holding time ranges from 90 to 100 minutes.
[0024] Furthermore, in step S5, the forging transfer time is ≤60s, and the cooling method is water cooling.
[0025] The beneficial effects of the present invention are as follows:
[0026] 1. Preforming is divided into two stages, which divides the deformation of large load into two steps of small load. The metal flows evenly during the deformation process, which improves the consistency of the forging structure and the forming accuracy of the forging. The load on the mold is small, which also increases the service life of the mold and avoids the small deformation load required. It can also increase the selectivity of the press tonnage.
[0027] 2. In the pre-formed punching, the mold base and the step form a snap-fit structure. The downward force of the hammer anvil and the upward force of the mold offset each other, and the mold does not get lifted by the interaction force. This improves the stability of deformation and achieves excellent adaptation between the blank and the cavity. The end face radius of the ring blank after forming is less than R5, and there is no edge collapse or meat shortage.
[0028] 3. The two-stage deformation is adopted to improve the punching accuracy and make the wall thickness of the ring blank uniform, thus avoiding the problem of extremely high eccentricity in traditional reverse extrusion closed blank making.
[0029] 4. At the solution temperature, the elements in the alloy will fully dissolve and form a uniform solid solution, eliminating the precipitation phase and grain boundary phase in the alloy, further improving the uniformity and plasticity of the alloy, and the carbides in the alloy will partially or completely dissolve into the solid solution, thereby improving the high temperature strength and oxidation resistance of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 Schematic diagram of the steps of a preforming method for high-temperature alloy forgings.
[0031] Figure 2 This is a structural diagram of tire mold one.
[0032] Figure 3 Schematic diagram of the strain field of the forging in the first step of membrane forging.
[0033] Figure 4 Schematic diagram of the temperature field of the forging in the first step of the membrane forging process.
[0034] Figure 5 Schematic diagram of the load curve of the forging in the first step of membrane forging.
[0035] Figure 6 This is a schematic diagram of the structure of tire mold 2.
[0036] Figure 7 Schematic diagram of the punch structure.
[0037] Figure 8 Schematic diagram of the strain field of the forging in the second step of membrane forging.
[0038] Figure 9 This is a schematic diagram of the temperature field of the forging in the second step of the membrane forging process.
[0039] Figure 10 This is a schematic diagram of the load curve of the forging in the second step of the membrane forging process.
[0040] Figure 11 This is a macrostructure diagram of the forging specimen.
[0041] In the figure: 1, tire mold 1; 2, tire mold 2; 21, step portion; 22, tire mold bottom film. DETAILED DESCRIPTION
[0042] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.
[0043] Example:
[0044] A method for preforming a high temperature alloy forging, such as Figure 1 As shown, the following steps are included:
[0045] Step S1, blanking, the material is HS188, the blanking size is: Φ130 (+3 / 0) × 175 (+3 / 0) mm, and the blanking weight is 21 (+0.5 / 0) kg.
[0046] Step S2, fetal membrane forging, includes step one and step two.
[0047] First, the blank is heated for forging, the temperature range is 1140±10℃, and the holding time range is 115~205min.
[0048] Step 1: Figure 2 As shown, the design includes a membrane 1, with an inner hole that tapers from top to bottom. The inner wall of membrane 1 is inclined at an angle of 82°, which is the angle used in this embodiment. Membrane 1 is preheated in advance to a temperature range of 250-350°C. The blank is placed in membrane 1 and upset at a hammer speed of 20-70 mm / s. The final forging temperature of the forging is ≥950°C, followed by a 50-minute re-melting hold at a temperature of 1140±10°C.
[0049] The strain field of the forging, such as Figure 3 As shown in Figure 2, the strain distribution is uniform and there is no local excessive strain.
[0050] The temperature field of the forging, such as Figure 4 As shown, the temperature in the forging structure is uniform, which is conducive to metal flow.
[0051] The load of the forging, such as Figure 5 As shown in the figure, there is no sudden increase in the load curve.
[0052] Step 2: Figure 6 As shown, the fetal membrane 2 is designed, and the fetal membrane 2 is provided with an inner hole with a diameter gradually decreasing from top to bottom, and the inner wall of the fetal membrane 2 is inclined at an angle of 88 degrees. The bottom of the inner hole is also provided with an inwardly extending step portion 21, and the fetal membrane bottom plate 22 is placed on the step portion.
[0053] Preheat the second membrane in advance, place the blank into the second membrane punch, press down the hammer at a speed of 20 to 70 mm / s, and the final forging temperature of the forging is ≥950°C. Then return to the furnace and keep warm for 50 minutes at a temperature of 1140±10°C. The final forging size is Φ190(+5 / 0)×Φ100(+5 / -2)×98(+3 / -3)mm.
[0054] Since the temperature of the blank making process is high, such as Figure 7 As shown, the punch used is the GH4169 punch, which has good high temperature resistance, avoids the hardness of the punch decreasing, and reduces the possibility of safety hazards. The bottom edge of the punch is rounded R5.
[0055] The strain field of the forging, such as Figure 8 As shown in Figure 2, the strain distribution is uniform and there is no local excessive strain.
[0056] The temperature field of the forging, such as Figure 9 As shown, the temperature in the forging structure is uniform, which is conducive to metal flow.
[0057] The load of the forging, such as Figure 10 As shown in the figure, there is no sudden increase in the load curve.
[0058] When the volume of the high-temperature alloy ring blank is large, the cavity volume is slightly larger or smaller than the actual material used, which has little impact on the ring blank's forming. In this case, regardless of the blanking method, a ring blank with acceptable dimensions can be forged. Conversely, the smaller the ring blank, the more precise the cavity design must be. Therefore, combined with finite element numerical simulation of the preforming process and observation of the deformation process, it can be seen that the bottom of the ring membrane is difficult to fill tightly, and the ring blank and the die are lifted together, causing some material to overflow from the lower end face. When the ring blank is large, this overflow has little impact on the loss of the upper end face, resulting in no significant large R angle on either end face and no impact on the overall forming. When the ring blank is small, any volume loss on the upper end face is likely to result in an excessively large R angle, requiring reshaping to eliminate the R angle. Otherwise, after the ring is rolled, the forging will not meet the required dimensions as per the drawing. In summary, the design of the ring membrane must draw on finite element numerical simulation to pre-judge the forming conditions. This determines the matching relationship between the blank weight and the die cavity, the relationship between the cavity form and the load, and the inclination angle of the inner wall of the ring membrane.
[0059] Step S3, pre-rolling,
[0060] Step S4: Ring rolling with dimensions of 205(+5 / -5)×130(+5 / -5)×98(+3 / -3)mm. The ring is then returned to the furnace for heating at 1140±10°C for 30 minutes, and the end face of the forging is then leveled.
[0061] Step S5, solutionizing: After ring rolling, the forging is transferred to a furnace for solutionizing at ≤1100°C, with the transfer time being less than 60 seconds. The solutionizing temperature range is 1177±14°C, and the holding time range is 90-100 minutes. It is then water-cooled to room temperature.
[0062] Finally, x parts are selected from each batch of parts for comprehensive physical and chemical performance testing.
[0063] The test results are as follows:
[0064] 1. Room temperature tensile test. Test results are shown in Table 1:
[0065]
[0066] Table 1
[0067] Analysis of test results:
[0068] Tensile strength: The tensile strength of the product is above 935Mpa, which exceeds the standard by nearly 80Mpa.
[0069] Yield strength: The yield strength of the product is above 450Mpa, which exceeds the standard by nearly 70~100Mpa.
[0070] Sectional shrinkage rate: The section shrinkage of the product is over 53%, exceeding the standard by nearly 8%.
[0071] At room temperature, the macroscopic indicators of the forgings meet the standards and have good mechanical properties, which indirectly shows that the forgings have uniform structure and achieve fine grain strengthening.
[0072] 2. Hardness test, test results are shown in Table 2:
[0073]
[0074] Table 2
[0075] The forgings are not too hard or brittle.
[0076] 3. High temperature endurance test, test results are shown in Table 3:
[0077]
[0078] Table 3
[0079] Analysis of test results:
[0080] Lifespan: The lifespan of the sample is over 35 hours, which exceeds the standard by nearly 12 hours.
[0081] Elongation: The elongation of the specimen is 84%, exceeding the standard requirement of 15%.
[0082] Under high temperature load, forgings have a long service life and high elongation, which reflects the good toughness of the structure.
[0083] 4. Forging structure inspection:
[0084] like Figure 11 As shown, the surface of the sample is evenly oxidized without overoxidation. The average depth of the single-sided oxidation penetration layer is 0.02173 mm. No metallurgical defects such as porosity, pinholes, cracks, shrinkage cavities and slag inclusions are found.
[0085] 5. Forging flaw detection:
[0086] The probe frequency is 5MHz, the amplitude of the defect display is no greater than the amplitude displayed by an equivalent flat-bottom hole with a diameter of 1.5mm, and the bottom wave loss does not exceed 6dB.
[0087] The ultrasonic detection signal loss does not exceed 6dB, and the forging ultrasonic detection is qualified.
[0088] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0089] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.
Claims
1. A method for preforming a high temperature alloy forging, characterized in that: The following steps are involved: Step S1, unloading: Step S2, fetal membrane forging, including step one and step two; In the first step, a fetal membrane is designed, wherein the fetal membrane is provided with an inner hole with a diameter gradually decreasing from top to bottom, and the forging blank is placed in the fetal membrane for upsetting, and then the forging is returned to the furnace for heat preservation; Step 2: designing a second fetal membrane, the second fetal membrane is provided with an inner hole with a diameter gradually decreasing from top to bottom, and a step portion extending inward is also provided at the bottom of the inner hole, a fetal membrane bottom sheet is placed on the step portion, and the forging is transferred to the second fetal membrane for punching; Step S3, pre-rolling; Step S4, ring rolling; Step S5, solution treatment, the solution temperature of the forging is 1177±14°C, and then cooling.
2. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: The inner wall inclination angle of the fetal membrane 1 ranges from 80 to 84 degrees, and the inner wall inclination angle of the fetal membrane 2 ranges from 87 to 89 degrees.
3. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In the first step of step S2, the heating temperature is 1140±10°C, and the holding time ranges from 115 to 205 minutes.
4. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In step 1 and step 2 of step S2, the working temperature of fetal membrane 1 and fetal membrane 2 is 250-350°C.
5. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In step 1 and step 2 of step S2, the final forging temperature of the forging is ≥ 950°C.
6. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In the first and second steps of step S2, the hammer head presses down at a speed of 20 to 70 mm / s.
7. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In step S3, the final forging temperature is ≥950°C, and after the deformation is completed, the steel is returned to the furnace for heating for 30 minutes to flatten the end surface.
8. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In step S4, the final forging temperature is ≥950°C, and after the deformation is completed, the steel is returned to the furnace for heating for 30 minutes to flatten the end surface.
9. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In step S5, the insulation time ranges from 90 to 100 minutes.
10. The method for preforming a high temperature alloy forging according to claim 1, characterized in that: In step S5, the forging transfer time is ≤60s, and the cooling method is water cooling.