Machining method of large-size copper blade

Abstract

The invention discloses a large-size copper blade machining method which comprises the following steps that S1, a blank is placed in a head upsetting tool to be subjected to head upsetting, and a head upsetting blank is obtained; s2, the pier head blank is placed in a pre-forging tool to be subjected to air entraining cavity size pre-forging forming so as to obtain a pre-forged blade, and the pre-forging tool is designed according to a deformation degree calculation formula of the pre-forged blade so as to guarantee that the deformation degree of the pre-forged blade meets the final forging requirement; and S3, the pre-forged blade is placed in a finish forging tool for air-entraining cavity size finish forging forming so as to obtain a finish-forged blade, the finish forging tool is designed according to a die cavity shrinkage amount calculation formula of the finish-forged blade, and the torsion angle amount is increased on the air-entraining cavity tangent plane, close to the blade tip, of the finish forging tool so as to ensure that the air-entraining cavity compensation allowance of the finish forging tool meets the requirement. Compared with the prior art, the air entraining cavity of the large-size copper blade obtained through machining is small and uniform in deformation and high in percent of pass, the production cost can be greatly reduced, and the method is suitable for wide application and popularization.

Description

Technical Field

[0001] The invention relates to the technical field of blade processing, and in particular to a processing method for a large-size copper blade. Background Art

[0002] At present, most of the copper blades in aircraft engines are small in size. The production of small-sized copper blades often adopts die forging technology, and its process flow is: heating-pre-forging-trimming-heating-pre-forging-trimming-heating-pre-forging-trimming-heating-pre-forging-precision pressing. The notable characteristics of this process are complicated procedures, multiple forging forming is required, the air bleed cavity is easy to deform, the margin cannot be compensated, the dimensional accuracy is not high, and it is easy to cause scrapping. The air bleed cavity needs to be machined for multiple adjustments to the processing benchmark forming, and the processing cost is high. However, since the air bleed cavity forming margin of small-sized copper blades is large (>1mm), and the size is small, the deformation is relatively small. Therefore, the above process can basically meet the processing requirements of small-sized copper blades.

[0003] However, a certain type of aircraft engine requires the use of large-sized copper blades (blade body > 200mm). The large-sized copper blades have relatively high requirements for the forming margin of the air entrainment cavity (less than 1mm), and the blades are large in size and have relatively large deformation. Therefore, when the above process is applied to the processing of large-sized copper blades, it is easy to cause large deformation of the air entrainment cavity of the large-sized copper blades, high scrap rate, and greatly increased production costs. Summary of the invention

[0004] The invention provides a method for processing a large-sized copper blade, so as to solve the technical problem that the deformation of the air entrainment cavity is large in the existing processing of the large-sized copper blade.

[0005] According to one aspect of the present invention, a processing method for large-sized copper blades is provided, comprising the following steps: S1, placing a blank into a header tool for headering to obtain a header blank, wherein the header tool is designed according to a volume calculation formula for a transition zone of the header blank to ensure that the volume of the transition zone of the header blank meets the pre-forging requirement; S2, placing the header blank into a pre-forging tool for pre-forging of an air-inducing cavity size to obtain a pre-forged blade, wherein the pre-forging tool is designed according to a deformation degree calculation formula for the pre-forged blade to ensure that the deformation degree of the pre-forged blade meets the final forging requirement; S3, placing the pre-forged blade into a final forging tool for final forging of an air-inducing cavity size to obtain a final forged blade, wherein the final forging tool is designed according to a cavity shrinkage calculation formula for the final forging blade, and a torsion angle is increased on the air-inducing cavity section near the blade tip of the final forging tool to ensure that the air-inducing cavity compensation margin of the final forging tool meets the requirement.

[0006] Furthermore, in step S1, the volume calculation formula of the transition zone of the pier head blank is:

[0007]

[0008] Among them, R1 is the short axis fillet of the elliptical transition zone of the pier head blank, R2 is the short axis fillet of the transition zone of the pier head blank, and H is the length between the pier head and the bottom of the rod.

[0009] Furthermore, in step S2, the deformation degree of the pre-forged blade is calculated by the formula:

[0010]

[0011] Among them, h0 is the maximum thickness of the pre-forged blade, h1 is the maximum thickness of the final forged blade, and ε is the maximum deformation degree allowed by the material.

[0012] Furthermore, in step S3, the calculation formula for the die cavity shrinkage of the final forged blade is:

[0013] A'=L(1+6%)×1.008

[0014] Among them, A' is the shrinkage of the special die cavity, L is the pre-forging size, and δ% is the blade shrinkage rate under the final forging temperature condition.

[0015] Furthermore, in step S3, the torsion angle should satisfy the following conditions:

[0016]

[0017] Among them, θ' is the twist angle, and α is the angle between the chord line of each section of the copper blade profile and the center line of the blade root.

[0018] Furthermore, in step S3, the air entrainment cavity compensation margin should meet the following conditions:

[0019] Among them, X is the compensation amount of the air entrainment cavity, P is the impact force required at the air entrainment cavity, h1 is the maximum thickness of the final forged blade, and h2 is the air entrainment cavity allowance.

[0020] Furthermore, in step S2, when the deformation degree of the pre-forged blade is between 20% and 30%, the final forging requirement is met.

[0021] Furthermore, before step S1, the method further includes the following step: S0, placing the blank into a heater, heating the blank to 720° C.-780° C., and keeping the temperature for 160 min-180 min.

[0022] Furthermore, between step S1 and step S2, there is also a step of heating the pre-forging tool to a temperature between 250°C and 350°C.

[0023] Furthermore, between step S2 and step S3, there is also a step of heating the final forging tool to between 250°C and 350°C.

[0024] The present invention has the following beneficial effects:

[0025] The processing method of the large-sized copper blade of the present invention first places the blank into the pier head tooling for piercing to obtain the pier head blank. Since the head of the pier head blank must be easy to enter the tenon of the pre-forging die cavity, and the inner edge surface of the tenon of the pre-forged blade must be full and free of defects, and the size of the head must be strictly controlled, the pier head tooling is designed according to the volume calculation formula of the transition zone of the pier head blank to ensure that the volume of the transition zone of the pier head blank meets the pre-forging requirements, and then ensure that the dimensional accuracy of the pier head blank meets the design requirements, so as to prepare for the subsequent pre-forging processing; then the pier head blank is placed in the pre-forging tooling for pre-forging of the air-inducing cavity size to obtain the pre-forged blade. Since the deformation degree of the pre-forged blade will have a certain influence on the dimensional accuracy of the final forged blade, if the deformation degree of the pre-forged blade is too large, it is easy to cause defects such as cracks in the blade during final forging. If the deformation degree of the pre-forged blade is too small, it is easy to cause organizational problems and lead to processing scrap. Therefore, according to the deformation degree of the pre-forged blade, the pier head blank is calculated. The pre-forging tooling is designed according to the calculation formula to ensure that the deformation degree of the pre-forged blade meets the final forging requirements, thereby preparing for the subsequent final forging process; finally, the pre-forged blade is placed in the final forging tooling for final forging of the air entrainment cavity size to obtain the final forged blade, and the final forging tooling is designed according to the calculation formula of the cavity shrinkage of the final forging blade, and the torsion angle is increased on the air entrainment cavity section near the blade tip of the final forging tooling to supplement the rebound damage to the air entrainment cavity during blade forging and heat treatment, and to ensure that the air entrainment cavity size of the final forging blade is within the accuracy range, thereby ensuring that the air entrainment cavity compensation margin of the final forging tooling meets the requirements, so that the margin compensation is performed when the air entrainment cavity of the final forging blade is finally formed to prevent the air entrainment cavity from deforming, and finally a large-sized copper blade with a small margin and uniform deformation of the air entrainment cavity is obtained. Compared with the prior art, the large-sized copper blade obtained by processing in this scheme has a small and uniform air entrainment cavity deformation, a high pass rate, can greatly reduce the production cost, has strong practicality, and is suitable for wide promotion and application.

[0026] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 It is a flowchart of the steps of a method for processing a large-sized copper blade according to a preferred embodiment of the present invention;

[0029] Figure 2It is a structural schematic diagram of a pier blank in a method for processing a large-sized copper blade according to a preferred embodiment of the present invention;

[0030] Figure 3 It is a structural schematic diagram of a pre-forged blade in a method for processing a large-sized copper blade according to a preferred embodiment of the present invention;

[0031] Figure 4 It is a schematic structural diagram of a final forged blade in a method for processing a large-size copper blade according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0033] like Figure 1-Figure 4 As shown, the processing method of the size copper blade of this embodiment is characterized in that it includes the following steps: S1, placing the blank into the pier head tooling for piercing to obtain the pier head blank, wherein the pier head tooling is designed according to the volume calculation formula of the transition zone of the pier head blank to ensure that the volume of the transition zone of the pier head blank meets the pre-forging requirements; S2, placing the pier head blank into the pre-forging tooling for pre-forging of the air entrainment cavity size to obtain the pre-forged blade, wherein the pre-forging tooling is designed according to the deformation degree calculation formula of the pre-forged blade to ensure that the deformation degree of the pre-forged blade meets the final forging requirements; S3, placing the pre-forged blade into the final forging tooling for final forging of the air entrainment cavity size to obtain the final forged blade, wherein the final forging tooling is designed according to the cavity shrinkage calculation formula of the final forging blade, and the torsion angle is increased on the air entrainment cavity section near the blade tip of the final forging tooling to ensure that the air entrainment cavity compensation margin of the final forging tooling meets the requirements.

[0034] like Figure 1-Figure 4As shown, specifically, the processing method of the large-sized copper blade of the present invention first places the blank into the pier head tooling for piercing to obtain the pier head blank. Since the head of the pier head blank must be easy to enter the tenon of the pre-forging die cavity, and the inner edge surface of the tenon of the pre-forged blade must be full and free of defects, the pier head tooling is designed according to the volume calculation formula of the transition zone of the pier head blank to ensure that the volume of the transition zone of the pier head blank meets the pre-forging requirements, and then ensure that the dimensional accuracy of the pier head blank meets the design requirements, so as to prepare for the subsequent pre-forging processing; then the pier head blank is placed in the pre-forging tooling for pre-forging of the air-inducing cavity size to obtain the pre-forged blade. Since the deformation degree of the pre-forged blade will have a certain influence on the dimensional accuracy of the final forged blade, if the deformation degree of the pre-forged blade is too large, it is easy to cause defects such as cracks in the blade during final forging. If the deformation degree of the pre-forged blade is too small, it is easy to cause organizational problems and lead to processing scrap. Therefore, according to the deformation degree of the pre-forged blade, the pier head blank is calculated. The pre-forging tooling is designed according to the calculation formula to ensure that the deformation degree of the pre-forged blade meets the final forging requirements, thereby preparing for the subsequent final forging process; finally, the pre-forged blade is placed in the final forging tooling for final forging of the air entrainment cavity size to obtain the final forged blade, and the final forging tooling is designed according to the calculation formula of the cavity shrinkage of the final forging blade, and the torsion angle is increased on the air entrainment cavity section near the blade tip of the final forging tooling to compensate for the rebound damage to the air entrainment cavity during blade forging, and to ensure that the air entrainment cavity size of the final forging blade is within the accuracy range, thereby ensuring that the air entrainment cavity compensation margin of the final forging tooling meets the requirements, so that the margin compensation is performed when the air entrainment cavity of the final forging blade is finally formed to prevent the air entrainment cavity from deforming, and finally a large-sized copper blade with a small margin and uniform deformation of the air entrainment cavity is obtained. Compared with the prior art, the large-sized copper blade obtained by processing in this scheme has a small and uniform air entrainment cavity deformation, a high pass rate, can greatly reduce the production cost, has strong practicality, and is suitable for wide promotion and application.

[0035] It should be understood that, in this embodiment, the final forged blade is a large-sized copper blade obtained by processing.

[0036] like Figure 2 As shown, in this embodiment, in step S1, the volume calculation formula of the transition zone of the pier head blank is:

[0037]

[0038] Among them, R1 is the short axis fillet of the elliptical transition zone of the pier head blank, R2 is the short axis fillet of the transition zone of the pier head blank, and H is the length between the pier head and the bottom of the rod.

[0039] Specifically, by designing and processing the pier head tooling through the above calculation formula, the dimensional accuracy tolerance of the pier head blank can be guaranteed to be ±0.3mm after the pier head tooling has pierced the blank. When the dimensional accuracy tolerance of the pier head blank exceeds 0.3mm, it will cause the subsequent pre-forged blades to be out of tolerance.

[0040] like Figure 3 As shown, in this embodiment, in step S2, the deformation degree calculation formula of the pre-forged blade is:

[0041]

[0042] Among them, h0 is the maximum thickness of the pre-forged blade, h1 is the maximum thickness of the final forged blade, and ε is the maximum deformation degree allowed by the material.

[0043] Specifically, by designing and processing the pre-forging tooling through the above calculation formula, after the pre-forging tooling pre-forges the pier head blank, cracks or structural problems in the air entrainment cavity of the pre-forged blank can be avoided, resulting in scrapping, thereby ensuring that the size of the pre-forged blank reaches the target accuracy.

[0044] In this embodiment, in step S2, the deformation degree of the pre-forged blade is between 20% and 30%, which meets the final forging requirements. Specifically, when the deformation degree of the pre-forged blade is between 20% and 30%, no cracks or structural problems will occur in the air entrainment cavity of the pre-forged blank; when the deformation degree of the pre-forged blank is less than 20%, it is easy to cause structural problems and lead to processing scrap; when the deformation degree of the pre-forged blank is greater than 30%, it is easy to cause defects such as cracks in the final forging of the blade.

[0045] like Figure 4 As shown, in this embodiment, in step S3, the calculation formula for the die cavity shrinkage of the final forged blade is:

[0046] A'=L(1+6%)×1.008

[0047] Among them, A' is the shrinkage of the special die cavity, L is the pre-forging size, and δ% is the blade shrinkage rate under the final forging temperature condition.

[0048] Specifically, the final forging tooling is designed and processed by the above calculation formula to ensure that the size of the air entrainment cavity in the die cavity is within the accuracy range.

[0049] In this embodiment, in step S3, the torsion angle should satisfy the following conditions:

[0050]

[0051] Among them, θ' is the twist angle, and α is the angle between the chord line of each section of the copper blade profile and the center line of the blade root.

[0052] Specifically, since the copper blade is long, thin and has a large twist angle, the springback phenomenon is more serious after heat treatment, the air entrainment cavity is more easily deformed, and the processing is easily scrapped. When designing the final forging tooling, the twist angle is increased on the air entrainment cavity section near the blade tip, and the twist angle is ensured to meet the above conditions to compensate for the springback loss of the air entrainment cavity during blade forging and heat treatment.

[0053] In this embodiment, in step S3, the air entrainment cavity compensation margin should meet the following conditions:

[0054] Among them, X is the compensation amount of the air entrainment cavity, P is the impact force required at the air entrainment cavity, h1 is the maximum thickness of the final forged blade, and h2 is the air entrainment cavity allowance.

[0055] Specifically, by ensuring that the compensation margin of the air inlet cavity of the final forging tooling meets the above conditions, the margin compensation is performed when the final forging tooling performs final forming of the air inlet cavity of the final forging blade to prevent deformation.

[0056] like Figure 1-Figure 4 As shown, in this embodiment, before step S1, the following steps are also included:

[0057] S0, place the blank in a heater and heat it to 720℃-780℃, and keep it warm for 160min-180min.

[0058] Specifically, the blank is placed in a heater and heated to 720°C-780°C, and kept warm for 160min-180min, and then the blank is pierced to eliminate the internal stress of the blank, improve the organizational structure, and enhance the material properties.

[0059] In this embodiment, the following steps are included between step S1 and step S2:

[0060] Heat the pre-forging tool to between 250℃-350℃.

[0061] Specifically, by heating the pre-forging tool to between 250℃-350℃ and then pre-forging the pier head blank, the pre-forging tool can be prevented from cracking and the temperature difference between the pre-forging tool and the pier head blank can be reduced, which greatly reduces the thermal stress of the surface layer, is beneficial to metal flow, and improves the quality of forgings.

[0062] In this embodiment, the steps between step S2 and step S3 further include:

[0063] Heat the final forging tool to between 250℃-350℃.

[0064] Specifically, by heating the final forging tool to between 250℃-350℃ and then performing final forging on the pre-forged blades, the final forging tool can be prevented from cracking and the temperature difference between the final forging tool and the pre-forged blade can be reduced, which greatly reduces the thermal stress on the surface, is beneficial to metal flow, and improves the quality of forgings.

[0065] In one embodiment, the processing steps of large-sized copper blades are as follows:

[0066] The blank is cut into Φ50mm×300mm size, placed in an electric furnace and heated to 750℃, kept warm for 180min and then taken out of the furnace; it is upset using a heading tool to obtain a pier head blank; the pier head blank is forged to the pre-compensated size of the air entrainment cavity margin using a pre-forging tool heated to 300℃; the final forging is performed using a final forging tool heated to 300℃ to obtain a final forged blade, which is a large-sized copper blade with a small margin and uniform deformation in the air entrainment cavity.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for processing large-size copper blades, characterized in that: The following steps are involved: S1, placing the blank into a pier head tooling for piering to obtain a pier head blank, wherein the pier head tooling is designed according to a volume calculation formula of a transition zone of the pier head blank to ensure that the volume of the transition zone of the pier head blank meets the pre-forging requirements; S2, placing the pier head blank into a pre-forging tool for pre-forging of the air-inducing cavity size to obtain a pre-forged blade, wherein the pre-forging tool is designed according to a deformation degree calculation formula of the pre-forged blade to ensure that the deformation degree of the pre-forged blade meets the final forging requirements; S3, placing the pre-forged blade into the final forging tool for final forging of the air entrainment cavity size to obtain the final forged blade, wherein the final forging tool is designed according to the calculation formula of the cavity shrinkage of the final forging blade, and the torsion angle is increased on the air entrainment cavity section near the blade tip of the final forging tool to ensure that the air entrainment cavity compensation margin of the final forging tool meets the requirements.

2. The method for processing a large-size copper blade according to claim 1, characterized in that: In step S1, the volume calculation formula of the transition zone of the pier head blank is: Among them, R1 is the short axis fillet of the elliptical transition zone of the pier head blank, R2 is the short axis fillet of the transition zone of the pier head blank, and H is the length between the pier head and the bottom of the rod.

3. The method for processing a large-size copper blade according to claim 1, characterized in that: In step S2, the deformation degree of the pre-forged blade is calculated by: Among them, h0 is the maximum thickness of the pre-forged blade, h1 is the maximum thickness of the final forged blade, and ε is the maximum deformation degree allowed by the material.

4. The method for processing a large-size copper blade according to claim 1, characterized in that: In step S3, the calculation formula for the die cavity shrinkage of the final forged blade is: A'=L(1+δ%)×1.008 Among them, A' is the shrinkage of the special die cavity, L is the pre-forging size, and δ% is the blade shrinkage rate under the final forging temperature condition.

5. The method for processing a large-size copper blade according to claim 1, characterized in that: In step S3, the torsion angle should satisfy the following conditions: Among them, θ' is the twist angle, and α is the angle between the chord line of each section of the copper blade profile and the center line of the blade root.

6. The method for processing a large-size copper blade according to claim 1, characterized in that: In step S3, the air-injection cavity compensation margin should meet the following conditions: Among them, X is the compensation amount of the air entrainment cavity, P is the impact force required at the air entrainment cavity, h1 is the maximum thickness of the final forged blade, and h2 is the air entrainment cavity allowance.

7. The method for processing a large-size copper blade according to claim 1, characterized in that: In step S2, when the deformation degree of the pre-forged blade is between 20% and 30%, the final forging requirement is met.

8. The method for processing a large-size copper blade according to any one of claims 1 to 7, characterized in that: Before step S1, the method further includes the following steps: S0, place the blank in a heater and heat it to 720℃-780℃, and keep it warm for 160min-180min.

9. The method for processing a large-size copper blade according to any one of claims 1 to 7, characterized in that: The steps between step S1 and step S2 include: Heat the pre-forging tool to between 250℃-350℃.

10. The method for processing a large-size copper blade according to any one of claims 1 to 7, characterized in that: The steps between step S2 and step S2 also include: Heat the final forging tool to between 250℃-350℃.

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