Isothermal extrusion forming method for journal forge piece
Through the near isothermal forging and extrusion forming method of annular blank, the problem of uneven deformation of GH4169 alloy journal forging during die forging and machine-plugging and opening of holes is solved, and uniform structure and high-quality forming of the forging are achieved.
Patent Information
- Application Number
- CN202311839784.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
The prior art is difficult to meet the problems of uneven deformation, unsatisfactory structure and impact on the quality of the forging parts during die forging and machine opening.
The near isothermal forging and extrusion forming method of annular blank is adopted to achieve uniform deformation and tissue optimization of the journal forging through the mold cavity design and control of the downward pressure speed, including heating, upsetting, punching, pre-rolling and chamfering treatment, combined with the downward pressure speed control of v1 and v2.
The deformation amount and tissue uniformity of the forging are improved, and the fine and uniform forged tissue is obtained, the strength and low-circumference fatigue performance of the forging are improved, the temperature rise is avoided, and the quality of the forging is improved.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a forming method, in particular to an isothermal extrusion forming method for a journal forging. Background Art
[0002] The GH4169 alloy journal forging is a hollow thin-walled special-shaped part. The upper end of the shape is a large flared opening, and the lower end is provided with a cylindrical barrel. The wall thickness at the flared opening is thin while the diameter is large, and the wall thickness of the barrel is relatively thin. Since this forging is a key rotating part of an aircraft engine and the working conditions are extremely harsh, it is required that the forging has high strength, fracture toughness, and good low-cycle fatigue performance, etc. It is very difficult to meet these performance requirements by using ordinary die forging and free forging. Currently, this type of forging is mainly formed by closed die forging of a bar blank and then produced by machining to drill holes. However, on the one hand, during die forging, uneven deformation occurs, and the deformation amount of the rod part is small, resulting in an unsatisfactory structure of the rod part of the forging, and complete, thick, straight and continuous grain boundary α-phase appears on the original β grain boundary of the rod part; on the other hand, machining to drill holes will cut off the forging streamline of the forging, thus affecting the quality of the forging. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a near-isothermal forging and extrusion forming method using an annular blank. During the extrusion forming process, the middle variable step of the mold cavity functions as an extrusion die, and the upper maximum outer diameter cavity functions as an extrusion cylinder, which greatly improves the deformation of the rod part of the journal forging. The deformation amount of the blank is large, which is beneficial to obtaining a fine and uniform forged structure.
[0004] To solve the above technical problem, the isothermal extrusion forming method for the journal forging of the present invention includes the following technical solutions:
[0005] Heat the GH4169 alloy bar stock cut according to specifications in a forging heating furnace. First, heat the bar stock to 880°C - 900°C for insulation, and the insulation time is calculated according to 0.4 min / mm - 0.6 min / mm; then raise the temperature to 990°C - 1020°C for insulation, and the insulation time is calculated according to 0.6 min / mm - 0.8 min / mm; after insulation, upset, punch, pre-roll the bar stock, and chamfer the upper part of the inner diameter and the lower part of the outer diameter to obtain a rectangular ring blank;
[0006] Place the rectangular ring blank into a forming mold, drive the upper mold to extrude at a downward pressure speed of v1 = 1.5 mm / s - 2 mm / s. When the upper mold and the lower mold are closed, reduce the downward pressure speed to v2 = (0.3 - 0.5)v1, extrude the intermediate blank until the forming is complete, and obtain the GH4169 alloy journal forging.
[0007] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0008] The isothermal extrusion forming method of the journal forging of the present invention increases the deformation amount during forging, fully breaks the original grains, and obtains a fine and uniform structure. The downward pressing speed is first v1 = 1.5 mm / s to 2 mm / s. When the upper die and the lower die are closed, the downward pressing speed is reduced to v2 = (0.3 - 0.5)v1, which not only prevents the temperature rise phenomenon but also can reasonably distribute the deformation amount of each part of the forging and obtain the best-matched tissue properties. Improving the uniformity of cooling after forging is beneficial to improving the uniformity of the forging structure and obtaining a forging structure with a high consistency in the cross-section state. Moreover, chamfers are made at the upper part of the inner diameter and the lower part of the outer diameter of the rectangular ring blank, so that the rectangular ring blank can better fit with the forming die. Brief Description of the Drawings
[0009] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.
[0010] Figure 1 It is a schematic structural diagram of a rectangular ring blank.
[0011] Figure 2 It is a schematic diagram of loading the rectangular ring blank into the die.
[0012] Figure 3 It is a schematic diagram of the upper die and the lower die being closed.
[0013] Figure 4 It is a schematic diagram of forging forming.
[0014] Figure 5 It is a schematic structural diagram of the journal forging. Specific Embodiments
[0015] To implement the isothermal extrusion forming method of the journal forging of the present invention, equipment such as a forging heating furnace, a press, and a manipulator need to be provided. The specific implementation method is as follows:
[0016] The main chemical element contents (weight percentages) of this GH4169 alloy are: C content ≤ 0.08%, Cr content 17.0% - 21.0%, Ni content 50.0% - 55.0%, Co content ≤ 1.0%, Mo content 2.80% - 3.30%, Al content 0.30% - 0.70%, Ti content 0.75% - 1.15%, Nb content 4.75% - 5.50%, B content ≤ 0.006%, Mg content ≤ 0.01%, Mn content ≤ 0.35%, Si content ≤ 0.35%, P content ≤ 0.015%, S content ≤ 0.015%, Cu content ≤ 0.30%, Ca content ≤ 0.01%, Pb content ≤ 0.0005%, Se content ≤ 0.0003%, and the balance is Fe.
[0017] The steps of this method are as follows:
[0018] Heat the GH4169 alloy bars cut according to specifications in a forging heating furnace. First, heat the bars to 880°C - 900°C and hold for a time calculated as 0.4 min / mm - 0.6 min / mm; then raise the temperature to 990°C - 1020°C and hold for a time calculated as 0.6 min / mm - 0.8 min / mm. After holding, perform upsetting, punching, pre-rolling, and chamfering on the bars to obtain a rectangular ring blank 3, as Figure 1 shown;
[0019] As Figure 2 shown, place the rectangular ring blank 3 into a forming die, and drive the upper die 1 to extrude at a downward pressing speed of v1 = 1.5 mm / s - 2 mm / s. When the upper die 1 and the lower die 2 are closed, as Figure 3 shown, reduce the downward pressing speed to v2 = (0.3 - 0.5)v1 and extrude the intermediate blank 4 until the forming is complete, as Figure 4 shown, to obtain a GH4169 alloy journal forging 5, as Figure 5 shown.
Claims
1. An isothermal extrusion forming method for a journal forging, characterized in that, The steps include: Heat the GH4169 alloy bars cut according to specifications in a forging heating furnace. First, heat the bars to 880°C - 900°C for insulation, and the insulation time is calculated according to 0.4 min / mm - 0.6 min / mm; then raise the temperature to 990°C - 1020°C for insulation, and the insulation time is calculated according to 0.6 min / mm - 0.8 min / mm; after insulation, upset, punch, pre-roll the bars, and chamfer the upper part of the inner diameter and the lower part of the outer diameter to obtain a rectangular ring blank; place the rectangular ring blank into a forming die, drive the upper die to extrude at a downward pressure speed of v1 = 1.5 mm / s - 2 mm / s. When the upper die and the lower die are closed, reduce the downward pressure speed to v2 = (0.3 - 0.5)v1, and extrude the intermediate blank until the forming is complete to obtain a GH4169 alloy journal forging.