A hot spinning forming process for super-thick sheet high-temperature alloy

Abstract

The present invention relates to the technical field of sheet metal spinning, and in particular to a hot spinning process for ultra-thick sheet metal high-temperature alloys, comprising the following steps: S1, preheating the original sheet metal; S2, using multiple passes of spinning to process the preheated original sheet metal to obtain a spun product; S3, heat-treating and cooling the spun product to obtain a semi-finished part; S4, using a single pass of die-attached spinning to shape the semi-finished part to obtain a finished part. The present invention uses a heat-assisted multi-pass spinning process + a single pass of die-attached spinning process to successfully process a high-temperature alloy blank of a certain thickness into a qualified grid-type part. The arc tangent method and the spinning trajectory processed along the normal line of the part are used to reduce the feed mark and improve the surface smoothness of the part.

Description

Technical Field

[0001] The invention relates to the technical field of sheet metal spinning, in particular to a hot spinning process for ultra-thick sheet metal high-temperature alloys. Background Art

[0002] Sheet metal rotating parts for aircraft engines are mostly processed using traditional welding and mold forming methods. However, the welding + forming process has disadvantages such as low strength of processed parts, poor processing accuracy, low material utilization, high tooling costs, long processing cycle, and difficulty in controlling welding deformation.

[0003] For large-size thick plate high-temperature alloy parts, the maximum outer diameter of the blank exceeds Φ1000mm and the sheet thickness is 5mm. If a straight blank is directly pressed into shape, the mold size will be too large and the mold outline size will exceed 1300mm. Processing such a mold will have a long processing cycle, high cost, and difficulty in mold repair; if multi-petal welding is used, a large number of blanks will be required, the blank utilization rate will be low, the welding qualification rate will be low, the welding deformation will be difficult to control, and the forming mold will still need to be calibrated after welding, which will result in high mold cost. Summary of the Invention

[0004] In view of the problems of complex process and long processing cycle in the prior art, the present invention provides a hot spin forming process for ultra-thick sheet high-temperature alloy.

[0005] The present invention is achieved through the following technical solutions:

[0006] A hot spin forming process for ultra-thick sheet high-temperature alloy includes the following steps:

[0007] S1, preheating the original sheet;

[0008] S2, using multiple passes of spinning to process the preheated raw sheet to obtain a spinning product;

[0009] S3, heat treating and cooling the spinning product to obtain a semi-finished part;

[0010] S4, using a one-pass die-spinning process to shape the semi-finished parts to obtain finished parts.

[0011] Preferably, in S2, the spinning wheel adopts an arc tangent method when feeding, adopts a spinning trajectory along the normal line of the part when processing, and adopts a spinning trajectory of an arc plus a straight line tangent when retracting.

[0012] Preferably, in S2, during spinning, an anti-deformation structure is provided on the mold, and the anti-deformation structure includes a first anti-deformation angle at the mold profile position and a second anti-deformation angle at the mold outer circle straight line position.

[0013] Preferably, the first anti-deformation angle is -1°.

[0014] Preferably, the second reverse deformation angle is -3°.

[0015] Preferably, in S1, the preheating temperature is 450°C to 500°C.

[0016] Preferably, in S2, the temperature during spinning is greater than or equal to 450°C, and the temperature during spinning is maintained and compensated by a heating flame spray gun.

[0017] Preferably, in S3, during the heat treatment, the heat-treated spinning product is combined with a heat-treated mold and then annealed at 950°C±10°C for 4 hours.

[0018] Preferably, in S3, furnace cooling is adopted during cooling.

[0019] Preferably, in S4, the semi-finished part is heated to 450°C to 500°C before shaping.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention discloses a hot spin forming process for ultra-thick sheet high-temperature alloy, which adopts a heat-assisted multi-pass spinning forming + a one-pass die-attaching spinning method to successfully process parts from a high-temperature alloy (GH3625) blank with a thickness of 5 mm into qualified grid parts.

[0022] Furthermore, the arc tangent method and the spinning trajectory along the part normal are used to reduce the feed mark and improve the surface finish of the part. The arc plus straight line tangent spinning trajectory is used to reduce the curl of the wheel rim.

[0023] Furthermore, the first anti-deformation angle is to avoid the phenomenon of non-adherence to the mold during the spinning process. Since the linear position of the outer circle of the mold is close to the outer circle of the large end of the part, and the linear speed of the rotating edge gradually increases, the rebound trend of the spinning process at this position is more obvious, so the second anti-deformation angle is set.

[0024] Furthermore, the temperature maintenance during spinning is to ensure the temperature of the parts to prevent the parts from dissipating too quickly during the spinning process, thereby causing a more obvious rebound trend. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the spinning roller passes. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain the present invention rather than to limit it.

[0027] The present invention discloses a hot spin forming process for ultra-thick sheet high-temperature alloy, comprising the following steps:

[0028] S1, preheating the original sheet material, wherein the preheating temperature is 450°C to 500°C.

[0029] S2, performing multiple spinning processes on the preheated raw sheet material under the condition that the spinning temperature is greater than or equal to 450° C. to obtain a spinning product.

[0030] The path of the rollers reciprocating as they roll the part's surface during spinning is collectively referred to as a pass. The surface finish, forming accuracy, and the likelihood of cracks and tears during the spinning process are closely related to the rationality of the pass design. Single-pass spinning is typically used when the spun part is made of easily formable materials such as aluminum and copper, or has a simple surface and minimal deformation. Using a single pass during trial processing can result in poor quality and a high risk of springback.

[0031] The motion trajectory of the spinning wheel in multi-pass deep drawing can be a straight line, an arc, a combination of a straight line and an arc, or a combination of arcs and arcs, or other smooth curves such as parabolas. The spinning tests with different trajectories were carried out in combination with the part surface and material properties. Figure 1 The arc tangent method is used when the spinning wheel feeds, the spinning trajectory is processed along the normal line of the part during processing, and the spinning trajectory of the arc plus straight line tangent is used when the tool is retracted.

[0032] During spinning, an anti-deformation structure is set on the mold, which includes a first anti-deformation angle at the mold surface position and a second anti-deformation angle at the mold outer circle straight line position, wherein the first anti-deformation angle is -1° and the second anti-deformation angle is -3°.

[0033] High-temperature alloy (GH3625) has high tensile strength and low elongation coefficient at room temperature. When spinning this material at room temperature, the blank exhibits a significant springback tendency. After machining to 1 / 2 diameter, the outer diameter completely curls upward, directly interfering with the roller rotation and rendering the part scrapped. As the heating temperature gradually increases during machining, the tensile strength of the high-temperature alloy (GH3625) decreases, while the elongation coefficient increases. This significantly reduces machining difficulty and improves forming accuracy. A heated flame spray gun is used to maintain and compensate for the temperature during spinning.

[0034] Selection of roller arc: After comparison during the trial processing of parts, the larger the roller arc, the higher the processing efficiency, but the lower the surface finish. The smaller the roller arc, the lower the processing efficiency and the higher the surface finish, but the excessive spinning of the blank surface will cause greater work hardening and more obvious part springback.

[0035] S3, heat treatment and cooling of the spinning product to obtain semi-finished parts.

[0036] During heat treatment, the heat-treated spinning product is combined with the heat-treated mold and then annealed at 950℃±10℃ for 4 hours. Furnace cooling is used for cooling.

[0037] S4, using a one-pass die-spinning process to shape the semi-finished part to obtain the finished part. Before shaping, the semi-finished part is heated to 450°C to 500°C.

[0038] Take the blank as an example. The material is a high-temperature alloy (GH3625) with a thickness of 5mm. The spin-formed part is a tapered part with a diameter of ΦAmm and a height of Bmm. The material has high strength and high processing resistance. It is easy to rebound during forming and curling occurs. The specific processing steps are as follows:

[0039] (1) Use a machine tool to copy the spinning mold, and design a safety distance (i.e., the gap between the spinning wheel and the core mold) of 3.8 mm to avoid overcutting during the spinning process and damaging the parts and the mold. After the copying is completed, the parts are clamped and tightened, and lubricating oil is applied. Enter the parameters such as the spinning roller pass, speed, and feed. In this embodiment, the spindle speed n is 100 rpm and the spinning wheel feed ratio fz is 0.8 mm / r.

[0040] (2) Start the equipment and use a flame spray gun to preheat the blank and mold at a low speed, heating the blank to 450℃~500℃.

[0041] (3) Start the program for spinning. During the spinning process, the spray gun continuously heats the blank along the spinning path to ensure that the temperature of the blank is not lower than 450°C. After spinning to 1 / 2 diameter, in order to compensate for heat dissipation, the number of heating flame spray guns is increased to 3, and the heating temperature is maintained at not lower than 450°C until the processing is completed.

[0042] (4) After the spinning process is completed, stop heating and continue to keep the equipment and mold rotating to allow the parts and mold to cool quickly in the air. After removing the parts, anneal them. Anneal the mold with the heat treatment to avoid deformation due to stress release during the heat treatment process. The heat treatment temperature is 950℃±10℃ and the heat treatment time is 4 hours. Cool with the furnace and do not allow air cooling. The parts can be taken out only after the parts and mold are completely cooled.

[0043] (5) After annealing, the part is re-clamped on the mold and preheated to 450℃~500℃ according to step (2). The processing parameters and mold are not adjusted. The part is shaped by one-pass die-spinning. After cooling, the part is removed, the wall thickness is measured, and the mold surface is inspected. The part processing process is completed.

[0044] The above are merely preferred embodiments of the present invention and are not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and replacements, and these modifications and replacements are also within the scope of protection covered by the claims.

Claims

1. A hot spin forming process for ultra-thick sheet high-temperature alloy, characterized in that: The following steps are involved: S1, preheating the original sheet; wherein the sheet thickness is 5mm; S2, using multiple spinning passes to process the preheated raw sheet to obtain a spinning product; Among them, the spinning wheel adopts the arc tangent method when feeding, adopts the spinning trajectory along the normal line of the part when processing, and adopts the spinning trajectory of arc plus straight line tangent when retracting; During spinning, an anti-deformation structure is set on the mold, which includes a first anti-deformation angle at the mold surface position and a second anti-deformation angle at the mold outer circle straight line position; the first anti-deformation angle is -1°; the second anti-deformation angle is -3°; S3, heat treating and cooling the spinning product to obtain a semi-finished part; S4, using a one-pass die-spinning process to shape the semi-finished parts to obtain finished parts.

2. The ultra-thick sheet high-temperature alloy hot spin forming process according to claim 1, characterized in that: In S1, the temperature during preheating is 450°C to 500°C.

3. The ultra-thick sheet high-temperature alloy hot spin forming process according to claim 1, characterized in that: In S2, the temperature during spinning is greater than or equal to 450°C, and the temperature during spinning is maintained and compensated by a heating flame spray gun.

4. The ultra-thick sheet high-temperature alloy hot spin forming process according to claim 1, characterized in that: In S3, during the heat treatment, the heat-treated spinning product is combined with the heat-treated mold and then annealed at 950°C ± 10°C for 4 hours.

5. The ultra-thick sheet high-temperature alloy hot spin forming process according to claim 1, characterized in that: In S3, furnace cooling is used for cooling.

6. The ultra-thick sheet high-temperature alloy hot spin forming process according to claim 1, characterized in that: In S4, the semi-finished parts are heated to 450°C to 500°C before shaping.

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