Method for machining large-size copper blades

Abstract

The application discloses a processing method of a large-size copper blade, which comprises the following steps: S1, placing a blank into a heading tool to perform heading to obtain a heading blank; S2, placing the heading blank into a preforming tool to perform air-guided cavity size preforming to obtain a preformed blade, wherein the preforming tool is designed according to a deformation degree calculation formula of the preformed blade to ensure that the deformation degree of the preformed blade meets final forging requirements; S3, placing the preformed blade into a final forging tool to perform air-guided cavity size final forging to obtain a final forged blade, wherein the final forging tool is designed according to a cavity shrinkage calculation formula of the final forged blade, and a torsion angle amount is added to a section of the air-guided cavity near a blade tip of the final forging tool to ensure that the air-guided cavity compensation allowance of the final forging tool meets requirements. Compared with the prior art, the air-guided cavity deformation amount of the large-size copper blade obtained by the method is small and uniform, the qualified rate is high, the production cost can be greatly reduced, and the method is suitable for being widely promoted and applied.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blade processing, in particular, to a processing method of large-size copper blade. BACKGROUND

[0002] At present, the copper blades in the aero-engine are mostly small size. The production of small-size copper blade often adopts die forging process, and the process flow is: heating-pre-forging-edge cutting-heating-pre-forging-edge cutting-heating-pre-forging-edge cutting-heating-pre-forging-finish pressing. The significant feature of the process is that the process is complicated, multiple forging forming is needed, the gas guide cavity is easy to deform, the allowance cannot be compensated, the size precision is not high, it is easy to lead to scrap, and the gas guide cavity needs to be machined to adjust the processing datum multiple times, the processing cost is high. However, since the forming allowance of the gas guide cavity of the small-size copper blade is relatively large (>1mm), and the size is small, the deformation amount is relatively small, so the above process can basically meet the processing requirements of the small-size copper blade.

[0003] However, a large-size copper blade (blade body >200mm) is needed in a certain type of aero-engine. The forming allowance requirement of the gas guide cavity of the large-size copper blade is relatively high (less than 1mm), and the size is large, so the deformation amount is relatively large. Therefore, when the above process is applied to the processing of the large-size copper blade, the deformation amount of the gas guide cavity of the large-size copper blade is large, the scrap rate is high, and the production cost is greatly increased. SUMMARY

[0004] The present application provides a processing method of large-size copper blade to solve the technical problem of large deformation of the gas guide cavity in the processing of the existing large-size copper blade.

[0005] According to one aspect of the present application, a processing method of large-size copper blade is provided, comprising the following steps: S1, placing a blank into a heading tooling to perform heading to obtain a heading blank, wherein the heading tooling is designed according to a volume calculation formula of the transition zone of the heading blank to ensure that the volume of the transition zone of the heading blank meets the pre-forging requirement; S2, placing the heading blank into a pre-forging tooling to perform size pre-forging forming of the gas guide cavity to obtain a pre-forging blade, wherein the pre-forging tooling is designed according to a deformation degree calculation formula of the pre-forging blade to ensure that the deformation degree of the pre-forging blade meets the finish forging requirement; S3, placing the pre-forging blade into a finish forging tooling to perform size finish forging forming of the gas guide cavity to obtain a finish forging blade, wherein the finish forging tooling is designed according to a die cavity shrinkage calculation formula of the finish forging blade, and a torsion angle amount is added to the gas guide cavity section near the blade tip of the finish forging tooling to ensure that the compensation allowance of the gas guide cavity of the finish forging tooling meets the requirement.

[0006] Further, in step S1, the volume calculation formula of the transition zone of the heading blank is:

[0007]

[0008] Wherein, R1 is the short axis of the round corner of the elliptical transition zone of the head blank, R2 is the short axis of the round corner of the transition zone of the head blank, and H is the length between the head and the bottom of the rod.

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

[0010]

[0011] Wherein, 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] Further, in step S3, the cavity shrinkage of the final-forged blade is calculated by the formula:

[0013] A' = L(1+6%) x 1.008

[0014] Wherein, A' is the special cavity shrinkage, L is the pre-forged size, and δ% is the blade shrinkage rate under the final-forged temperature condition.

[0015] Further, in step S3, the twist angle amount should meet the following conditions:

[0016]

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

[0018] Further, in step S3, the air-bleeding cavity compensation amount should meet the following conditions:

[0019]

[0020] Wherein, X is the air-bleeding cavity compensation amount, P is the required impact force of the air-bleeding cavity position, h1 is the maximum thickness of the final-forged blade, and h2 is the air-bleeding cavity allowance.

[0021] Further, in step S2, the deformation degree of the pre-forged blade is between 20% and 30%, which meets the final-forging requirements.

[0022] Further, before step S1, there is also a step S0 of placing the blank into a heater to heat it to 720-780°C and keeping it for 160-180 min.

[0023] Further, between step S1 and step S2, there is also a step of heating the pre-forging tooling to 250-350°C.

[0024] Further, between step S2 and step S2, there is also a step of heating the final-forging tooling to 250-350°C.

[0025] The present application has the following advantages:

[0026] The processing method of the large-size copper blade of the present application first places the blank into a heading tooling to perform heading to obtain a heading blank. Since the head of the heading blank needs to easily enter the mortise slot of the preforming die cavity and also needs to ensure that the inner edge surface of the tenon of the preformed blade is full of no defects, and the size of the head needs to be strictly controlled, therefore, the heading tooling is designed according to the volume calculation formula of the transition zone of the heading blank to ensure that the volume of the transition zone of the heading blank meets the preforming requirements, and further ensure that the size precision of the heading blank meets the design requirements, thereby preparing for the subsequent preforming processing. Then, the heading blank is placed into the preforming tooling to perform the size preforming of the air-guiding cavity to obtain a preformed blade. Since the deformation degree of the preformed blade will have a certain influence on the size precision of the final forged blade, if the deformation degree of the preformed blade is too large, it is easy to cause cracks and other defects during the final forging of the blade, and if the deformation degree of the preformed blade is too small, it is easy to cause organization problems to cause processing scrap, therefore, the preforming tooling is designed according to the deformation degree calculation formula of the preformed blade to ensure that the deformation degree of the preformed blade meets the final forging requirements, thereby preparing for the subsequent final forging processing. Finally, the preformed blade is placed into the final forging tooling to perform the size final forging of the air-guiding cavity to obtain a final forged blade. The final forging tooling is designed according to the die cavity shrinkage calculation formula of the final forged blade, and a torsion angle amount is added to the air-guiding cavity section near the tip of the final forging tooling to supplement the springback damage of the air-guiding cavity during the blade forging and heat treatment, and to ensure that the size of the air-guiding cavity of the final forged blade is within the precision range, thereby ensuring that the air-guiding cavity compensation allowance of the final forging tooling meets the requirements, thereby compensating for the allowance when the air-guiding cavity of the final forged blade is finally formed, to prevent the deformation of the air-guiding cavity, and finally obtain a large-size copper blade with small allowance uniform deformation of the air-guiding cavity. Compared with the prior art, the air-guiding cavity deformation of the large-size copper blade obtained by the present application is small and uniform, the qualified rate is high, the production cost can be greatly reduced, the practicality is strong, and the present application is suitable for wide promotion and application.

[0027] In addition to the objects, features, and advantages described above, the present application has other objects, features, and advantages. The present application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The illustrations are shown for the purpose of explaining the present application, and are not intended to be an improper limitation of the present application. In the drawings:

[0029] Figure 1 is a step block diagram of the processing method of the large-size copper blade of the preferred embodiment of the present application;

[0030] Figure 2is a structure schematic view of a pier head blank in a processing method of a large-size copper blade of a preferred embodiment of the present application;

[0031] Figure 3 is a structure schematic view of a pre-forged blade in a processing method of a large-size copper blade of a preferred embodiment of the present application;

[0032] Figure 4 is a structure schematic view of a final-forged blade in a processing method of a large-size copper blade of a preferred embodiment of the present application. DETAILED DESCRIPTION

[0033] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following.

[0034] As shown in Figures 1-4 , the processing method of the large-size copper blade of the present embodiment is characterized in that it comprises the following steps: S1, placing a blank into a pier head tooling for pier heading to obtain a pier head blank, wherein the pier head tooling is designed according to a 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 requirement; S2, placing the pier head blank into a pre-forging tooling for air-lead cavity size pre-forging forming to obtain a pre-forged blade, wherein the pre-forging tooling 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 requirement; S3, placing the pre-forged blade into a final-forging tooling for air-lead cavity size final-forging forming to obtain a final-forged blade, wherein the final-forging tooling is designed according to a die cavity shrinkage calculation formula of the final-forged blade, and a torsion angle amount is added to the air-lead cavity section surface at the near-blade-tip of the final-forging tooling to ensure that the air-lead cavity compensation allowance of the final-forging tooling meets the requirement.

[0035] As shown in Figures 1-4As shown, specifically, the processing method of large-sized copper blades of the present invention is to first place 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 pier head blank transition zone to ensure that the volume of the pier head blank transition zone meets the pre-forging requirements, and then ensure that the dimensional accuracy of the pier head blank meets the design requirements, thereby preparing for subsequent pre-forging processing; then the pier head blank is placed in the pre-forging tooling for air-inducing cavity size pre-forging 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 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 cavity size to obtain the final forged blade, and the final forging tooling is designed according to the calculation formula of the mold cavity shrinkage of the final forging blade, and the torsion angle is increased on the air cavity section near the blade tip of the final forging tooling to compensate for the rebound damage to the air cavity during blade forging, and to ensure that the air cavity size of the final forging blade is within the accuracy range, thereby ensuring that the air cavity compensation margin of the final forging tooling meets the requirements, so that the margin compensation is performed when the air cavity of the final forging blade is finally formed to prevent the air cavity from deforming, and finally a large-sized copper blade with a small margin and uniform deformation of the air cavity is obtained. Compared with the existing technology, the large-sized copper blade obtained by processing in this scheme has a small and uniform air cavity deformation, a high pass rate, can greatly reduce production costs, has strong practicality, and is suitable for wide promotion and application.

[0036] It should be understood that, in this embodiment, the final forged blade is a large-sized copper blade obtained by processing.

[0037] 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:

[0038]

[0039] 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.

[0040] 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.

[0041] As Figure 3 shown in the embodiment, in step S2, the deformation degree of the pre-forged blade is calculated by the formula:

[0042]

[0043] wherein 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.

[0044] Specifically, by using the above formula to design and process the pre-forging tool, after the pre-forging tool pre-forges the pier head blank, the crack or organization problem of the air-inlet cavity part of the pre-forged blank can be avoided, and the size of the pre-forged blank can reach the target precision.

[0045] In the embodiment, in step S2, the deformation degree of the pre-forged blade is between 20% and 30%, which meets the final-forging requirement. Specifically, when the deformation degree of the pre-forged blade is between 20% and 30%, the air-inlet cavity part of the pre-forged blank will not have cracks or organization problems; when the deformation degree of the pre-forged blank is less than 20%, it is easy to cause organization problems and lead to processing scrap; and when the deformation degree of the pre-forged blank is greater than 30%, it is easy to cause cracks and other defects in the blade during final forging.

[0046] As Figure 4 shown in the embodiment, in step S3, the cavity shrinkage of the final-forged blade is calculated by the formula:

[0047] A' = L(1+6%) x 1.008

[0048] wherein A' is the special cavity shrinkage, L is the pre-forging size, and δ% is the blade shrinkage rate under the final-forging temperature condition.

[0049] Specifically, the final-forging tool is designed and processed by using the above formula, so that the size of the air-inlet cavity in the cavity is within the precision range.

[0050] In the embodiment, in step S3, the twist angle amount should meet the following conditions:

[0051]

[0052] wherein θ' is the twist angle amount, and α is the included angle between the chord line of each section of the copper blade profile and the center line of the blade root.

[0053] Specifically, since the copper blade profile is long and thin and has a large twist angle, the springback phenomenon is more serious after heat treatment, and the air-inlet cavity part is more prone to deformation, which is prone to processing scrap. Therefore, when designing the final-forging tool, the twist angle amount is increased on the air-inlet cavity section near the blade tip, and the twist angle amount is ensured to meet the above conditions, so as to compensate for the springback loss of the air-inlet cavity during blade forging and heat treatment.

[0054] In the embodiment, in step S3, the air-duct cavity compensation allowance should satisfy the following condition:

[0055]

[0056] Wherein, X is the air-duct cavity allowance compensation, P is the required impact force of the air-duct cavity part, h1 is the maximum thickness of the final forging blade, and h2 is the air-duct cavity allowance.

[0057] Specifically, by ensuring that the air-duct cavity compensation allowance of the final forging tooling satisfies the above condition, the allowance compensation is performed when the final forging tooling performs the final forming of the air-duct cavity of the final forging blade, and the deformation is prevented.

[0058] As shown in the embodiment, before step S1, the following step is further included: Figures 1-4

[0059] S0, the blank is placed in a heater and heated to 720-780℃ and kept for 160-180min.

[0060] Specifically, by placing the blank in a heater and heating it to 720-780℃ and keeping it for 160-180min, and then heading, the internal stress of the blank is eliminated, the microstructure is improved, and the material performance is improved.

[0061] In the embodiment, between step S1 and step S2, the following step is further included:

[0062] The pre-forging tooling is heated to 250-350℃.

[0063] Specifically, by heating the pre-forging tooling to 250-350℃, the pre-forging of the heading blank is performed, so as to prevent the pre-forging tooling from breaking, reduce the temperature difference between the pre-forging tooling and the heading blank, greatly reduce the thermal stress of the surface layer, and also facilitate the flow of metal and improve the quality of the forgings.

[0064] In the embodiment, between step S2 and step S2, the following step is further included:

[0065] The final forging tooling is heated to 250-350℃.

[0066] Specifically, by heating the final forging tooling to 250-350℃, the final forging of the pre-forging blade is performed, so as to prevent the final forging tooling from breaking, reduce the temperature difference between the final forging tooling and the pre-forging blade, greatly reduce the thermal stress of the surface layer, and also facilitate the flow of metal and improve the quality of the forgings.

[0067] In an embodiment, the processing steps of the large-size copper blade are as follows:

[0068] ​After blanking the blank according to Φ50mm*300mm, the blank is placed into an electric furnace and heated to 750 DEG C, and after holding for 180 min, the blank is taken out of the furnace; a heading head is formed by using a heading head tooling, and after the heading head blank is obtained; the heading head blank is forged to a pre-compensation size of the air guide cavity allowance by using a pre-forging tooling heated to 300 DEG C; final forging is performed by using a final forging tooling heated to 300 DEG C, so as to obtain a final forging blade, which is a large-size copper blade of the air guide cavity small allowance uniform deformation.

[0069] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of machining a large size copper blade, characterized by, The method comprises the following steps: S1, placing the blank into a heading tool for heading to obtain a heading blank, wherein the heading tool is designed according to a volume calculation formula of a transition zone of the heading blank to ensure that the volume of the transition zone of the heading blank meets the requirement of preforming; S2, placing the heading blank into a preforming tool for air-duct cavity size preforming to obtain a preformed blade, wherein the preforming tool is designed according to a deformation degree calculation formula of the preformed blade to ensure that the deformation degree of the preformed blade meets the requirement of finish forming; S3, placing the preformed blade into a finish forming tool for air-duct cavity size finish forming to obtain a finish formed blade, wherein the finish forming tool is designed according to a die cavity shrinkage calculation formula of the finish formed blade, and a torsion angle amount is added to a section of the air-duct cavity near the tip of the blade in the finish forming tool to ensure that the air-duct cavity compensation allowance of the finish forming tool meets the requirement. In step S3, the torsion angle amount should meet the following condition: Wherein θ' is the torsion angle amount, and α is the included angle between the chord of each section of the blade profile and the center line of the blade root.

2. The method of processing large size copper blades according to claim 1, wherein, In step S2, the deformation degree calculation formula of the preformed blade is: Wherein h0 is the maximum thickness of the preformed blade, h1 is the maximum thickness of the finish formed blade, and ε is the maximum allowable deformation degree of the material.

3. The method of processing large size copper leaf according to claim 1, wherein, In step S3, the die cavity shrinkage calculation formula of the finish formed blade is: A' = L(1+δ%)×1.008 Wherein A' is the special die cavity shrinkage, L is the preforming size, and δ% is the blade shrinkage under the finish forming temperature condition.

4. The method of processing large size copper leaf according to claim 1, wherein, In step S3, the air-duct cavity compensation allowance should meet the following condition: Wherein X is the air-duct cavity allowance compensation amount, P is the required impact force of the air-duct cavity position, h1 is the maximum thickness of the finish formed blade, and h2 is the air-duct cavity allowance.

5. The method of processing large size copper leaf according to claim 1, wherein, In step S2, the deformation degree of the preformed blade is between 20% and 30% to meet the requirement of finish forming.

6. The method of processing large size copper blades according to any one of claims 1 to 5, wherein Before step S1, the method further comprises the following step: S0, placing the blank into a heater to heat to 720-780℃ and keeping for 160-180min.

7. The method of processing large size copper blades according to any one of claims 1 to 5, wherein Between step S1 and step S2, the method further comprises the following step: Heating the preforming tool to 250-350℃.

8. The method of processing large size copper blades according to any one of claims 1 to 5, wherein Between step S2 and step S3, the method further comprises the following step: Heating the finish forming tool to 250-350℃.

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