Blank making process before forming of inner star wheel

Abstract

The invention discloses a blank making process before forming of an inner star wheel, which comprises the following steps: S01, pre-selection and pretreatment of a bar, S02, pre-forming processing, S03, shot blasting treatment, S04, phosphorus saponification treatment, S05, extrusion forming, S06, inspection and correction after forming, and S07, inspection and packaging of a finished product, the shape of the bar is accurately adjusted through a pre-forming process, so that a large head and a small head are formed at the two ends of the bar, and the inner star wheel is formed. Therefore, the bar can be smoothly put into the die cavity; according to the design, not only is the adaptability of the bar and the die cavity improved, but also the adjustment time and the die replacement time caused by size mismatching in the production process are shortened; through the pre-forming process, the shape of the bar stock is optimized to accommodate the internal structure of the die cavity, which helps to distribute pressure more uniformly during forging.

Description

Technical Field

[0001] The invention relates to the technical field of a blank making process before inner star wheel forming, in particular to a blank making process before inner star wheel forming. Background Art

[0002] In the automobile transmission system, the inner star wheel is a key transmission component, and its performance directly affects the driving efficiency and safety of the car. The traditional inner star wheel manufacturing process mainly uses cold forging one-step forming technology. Although this technology can realize the forming of the inner star wheel, there are many technical defects and challenges in the actual production process.

[0003] First, since the original process is cold forging, the required forming tonnage is high, which puts high demands on forging equipment and increases production costs. Secondly, due to the folding of the outer diameter of the forging, it not only reduces the service life of the mold, but also increases the scrap rate of the workpiece. In addition, when the diameter of the bar before forming is small, the forming deformation is too large, resulting in high forming pressure and defects; when the diameter of the bar is large, it is easy to damage the lower die when it is placed in the lower die cavity, causing damage to the mold.

[0004] For the forging production of the eight-groove inner star wheel, these defects in the prior art lead to low production efficiency and unstable product quality. Therefore, it is necessary to develop a new inner star wheel blanking process to solve the problems existing in the prior art, improve production efficiency and product quality, and reduce production costs.

[0005] The purpose of the present invention is to provide a one-step forming billet making scheme for an inner star wheel, by improving the shape of the billet before forming and optimizing the forging process parameters to reduce the forming pressure, reduce the risk of die damage, and reduce the appearance defects of the forgings, thereby improving the production efficiency and product quality of the inner star wheel. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a blanking process before inner star wheel forming, which solves the problems of high forming tonnage, short die life, high workpiece scrap rate and sensitivity to bar diameter in the existing inner star wheel cold forging one-time forming process proposed in the background technology.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a blank making process before forming an inner star wheel, the steps of which are as follows: S01. Pre-selection and pre-treatment of bar stock: Select bar stock with appropriate diameter according to the design requirements of the inner star wheel; pre-treat the bar stock, including cleaning and removing surface defects, to ensure the smooth progress of the subsequent forming process; S02. Preforming: Preforming the bar material to improve the shape of the blank before forming so that it can meet the shape requirements of the mold cavity; the diameter and length of the reducer after preforming are determined through calculation and testing to reduce the forming pressure and eliminate appearance defects; S03. Shot blasting: Shot blasting is performed on the preformed bar material to remove the oxide scale and impurities on the surface, and at the same time improve the surface roughness of the material to prepare for the subsequent phosphorus saponification treatment; S04. Phosphorus saponification treatment: The shot blasted bars are subjected to phosphorus saponification treatment to form a protective film to reduce friction and wear during forging and increase die life; S05. Extrusion: Put the phosphorus saponified rod into the extruder and form it into the required inner star wheel shape by applying pressure; monitor the pressure and temperature during the extrusion process to ensure the forming quality; S06. Inspection and correction after forming: Check the inner star wheel after extrusion forming to ensure that its size and shape meet the design requirements; if there are defects, make necessary corrections to ensure that the appearance of the forging is free of defects; S07. Finished product inspection and packaging: Carry out final quality inspection on the corrected inner star wheel, including dimensional accuracy and surface quality; qualified products are cleaned, rust-proofed, and packaged for storage or shipment.

[0008] Preferably, in step S01, the pretreatment of the rod material includes cleaning with an ultrasonic cleaner for at least 5 minutes to remove oil and dust on the surface, followed by sandblasting to remove the surface oxide layer to ensure that the surface roughness reaches Ra≤3.2μm.

[0009] Preferably, in step S02, the diameter and length of the large and small heads after preforming are determined by finite element simulation calculation, wherein the large head diameter D1 is 1.05 to 1.15 times the original bar diameter D0, and the length L1 is 0.9 to 1.1 times the original bar length L0.

[0010] Preferably, in step S03, the diameter of the steel shot used for shot blasting is 0.5 to 1.0 mm, the shot blasting speed is 60 to 80 m / s, and the shot blasting time is controlled at 2 to 3 minutes to ensure uniform surface roughness of the material.

[0011] Preferably, in step S04, the concentration of the phosphorus saponification treatment solution is controlled at 5% to 10%, the treatment temperature is 60 to 80° C., and the treatment time is controlled at 5 to 10 minutes to form a uniform phosphorus saponification film.

[0012] Preferably, in step S05, the pressure during the extrusion process is controlled at 300 to 500 MPa, the temperature is controlled at 900 to 1100° C., and the extrusion speed is 0.5 to 1.5 m / min to ensure accurate forming of the inner star wheel shape.

[0013] Preferably, in step S07, the finished product inspection includes using a three-coordinate measuring machine to perform dimensional accuracy inspection with an inspection accuracy of ±0.02 mm, and surface quality inspection is performed using a roughness meter to ensure that the surface roughness Ra ≤ 1.6 μm. Qualified products are coated with anti-rust oil and vacuum packaged.

[0014] Preferably, in step S01, the pretreatment of the bar material further includes performing magnetic particle inspection to detect cracks or other discontinuities inside the bar material to ensure that the internal quality of the bar material meets the forming requirements.

[0015] Preferably, in step S03, the rod material is preheated after shot blasting, and the preheating temperature is controlled at 400° C. to 500° C. to reduce thermal shock during phosphorus saponification treatment and improve adhesion of the phosphorus saponification film.

[0016] Preferably, in step S06, the post-forming inspection and correction also includes testing the hardness of the inner star wheel, using a Rockwell hardness tester to measure the hardness value of the inner star wheel to ensure that the hardness value is within a specified range to meet the performance requirements of subsequent use.

[0017] The present invention provides a blanking process before forming an inner star wheel. It has the following beneficial effects: (1) Improved compatibility between the bar and the mold cavity and enhanced production efficiency: The present invention uses a pre-forming process to accurately adjust the shape of the bar so that its two ends form large and small heads, thereby ensuring that the bar can be smoothly placed in the mold cavity; this design not only improves the compatibility between the bar and the mold cavity, but also reduces the adjustment and mold replacement time caused by size mismatch during the production process; in addition, by reducing the adjustment time of the bar in the mold cavity, the overall efficiency of the production line is improved, thereby increasing the output per unit time without adding additional equipment.

[0018] (2) Significant improvement in forging stability and extended die life: Through the preforming process, the shape of the bar is optimized to adapt to the internal structure of the die cavity, which helps to distribute the pressure more evenly during the forging process; this uniform pressure distribution reduces local stress concentration on the die, thereby reducing the risk of die wear and damage; in addition, the uniformity of the preformed bar also helps to reduce uneven deformation during the forging process, further reducing the incidence of forging defects and improving the overall quality of the forging.

[0019] (3) Effective elimination of appearance defects and overall improvement of product quality: The present invention significantly reduces appearance defects that may occur during the forging process, such as folding and collapsed angles, by adjusting the shape of the blank before forming. This improvement is achieved by precisely controlling the shape and size of the bar head, ensuring a more uniform flow of the material in the die cavity, thereby reducing defects caused by uneven material flow. In addition, by reducing appearance defects, not only the visual quality of the product is improved, but also the structural integrity and durability of the product are enhanced, thereby improving the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process of the present invention; Figure 2 This is a schematic diagram of defects of ordinary billet after cold forging; Figure 3 This is a schematic diagram of the improved inner star wheel blank. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0022] A blank making process before forming an inner star wheel comprises the following steps: S01. Pre-selection and pre-treatment of bar stock: Select bar stock with a diameter of φ100mm, clean it with an ultrasonic cleaner for at least 5 minutes to remove oil and dust on the surface, and then perform sandblasting to remove the surface oxide layer to ensure that the surface roughness reaches Ra≤3.2μm. In addition, perform magnetic particle inspection to detect cracks or other discontinuities inside the bar stock.

[0023] S02. Pre-forming processing: Pre-forming the bar material to improve the shape of the blank before forming so that it can adapt to the shape requirements of the mold cavity.

[0024] S03. Shot blasting: Use steel shot with a diameter of 0.75mm, the shot blasting speed is 70m / s, and the shot blasting time is controlled within 2 to 3 minutes to ensure uniform surface roughness of the material.

[0025] S04. Phosphorus saponification treatment: The concentration of the treatment solution is controlled at 7.5%, the treatment temperature is 70°C, and the treatment time is controlled at 7 minutes to form a uniform phosphorus saponification film.

[0026] S05. Extrusion forming: The pressure is controlled at 400MPa, the temperature is controlled at 1000℃, and the extrusion speed is 1m / min to ensure the precise forming of the inner star wheel shape.

[0027] S06. Inspection and correction after forming: Use Rockwell hardness tester to measure the hardness value of the inner star wheel to ensure that the hardness value is within the specified range to meet the performance requirements of subsequent use.

[0028] S07. Finished product inspection and packaging: Use a three-coordinate measuring machine to test the dimensional accuracy, with a test accuracy of ±0.02mm. Use a roughness meter to test the surface quality, ensuring that the surface roughness Ra≤1.6μm. Qualified products are coated with anti-rust oil and vacuum packaged. Example 2

[0029] A blank making process before forming an inner star wheel comprises the following steps: S01. Pre-selection and pre-treatment of bar materials: Select bars with a diameter of φ120mm, perform ultrasonic cleaning and sandblasting, and make the surface roughness reach Ra≤3.2μm, and perform magnetic particle inspection.

[0030] S02. Pre-forming processing: Pre-forming the bar material to improve the shape of the blank before forming so that it can adapt to the shape requirements of the mold cavity.

[0031] S03. Shot blasting: Use steel shot with a diameter of 0.6 mm, a shot blasting speed of 65 m / s, and a shot blasting time of 3 minutes.

[0032] S04. Phosphorus saponification treatment: the treatment solution concentration is 8%, the treatment temperature is 75°C, and the treatment time is 8 minutes.

[0033] S05. Extrusion molding: the pressure is controlled at 450MPa, the temperature is controlled at 1050℃, and the extrusion speed is 1.2m / min.

[0034] S06. Inspection and correction after forming: Check the size and shape, correct any defects, and test the hardness value.

[0035] S07. Finished product inspection and packaging: Dimensional accuracy inspection, surface roughness Ra≤1.6μm, anti-rust oil coating and vacuum packaging. Example 3

[0036] A blank making process before forming an inner star wheel comprises the following steps: S01. Pre-selection and pre-treatment of bar materials: Select bars with a diameter of φ150mm, perform ultrasonic cleaning and sandblasting, and make the surface roughness reach Ra≤3.2μm, and perform magnetic particle inspection.

[0037] S02. Preforming: Preforming the bar to improve the shape of the blank before forming so that it can adapt to the shape requirements of the mold cavity; after preforming, the big head diameter D1 is 1.08 times the original bar diameter, and the length L1 is 1.02 times the original bar length.

[0038] S03. Shot blasting: Use steel shot with a diameter of 0.8 mm, a shot blasting speed of 75 m / s, and a shot blasting time of 2.8 minutes.

[0039] S04. Phosphorus saponification treatment: the treatment solution concentration is 6%, the treatment temperature is 65°C, and the treatment time is 6 minutes.

[0040] S05. Extrusion molding: the pressure is controlled at 350MPa, the temperature is controlled at 950℃, and the extrusion speed is 0.8m / min.

[0041] S06. Inspection and correction after forming: Check the size and shape, correct any defects, and test the hardness value.

[0042] S07. Finished product inspection and packaging: Dimensional accuracy inspection, surface roughness Ra≤1.6μm, anti-rust oil coating and vacuum packaging.

[0043] Comparative Example 1: Traditional inner star wheel forming process A conventional blank making process before forming an inner star wheel comprises the following steps: Bar selection: Select bars with diameters that meet basic requirements, do not perform specific pre-forming processing, and directly use the original size for subsequent processes; Bar pre-treatment: basic surface cleaning is performed to remove obvious oil and dust, but ultrasonic cleaning and sandblasting are not included, so the surface roughness may not fully meet the specific standards; Shot blasting: may not be performed or different parameters may be used, with no particular emphasis on uniformity of surface roughness to simplify the process; Phosphorus saponification treatment: This step may be omitted, or different treatment solution concentrations, temperatures, and times may be used without guaranteeing the uniformity of the phosphorus saponification film, in order to reduce process complexity; Extrusion molding: It is carried out without preforming and phosphorus saponification treatment. The molding pressure and molding quality may be different from those in the embodiment, but the basic molding requirements are met; Post-forming inspection and correction: Carry out routine size and shape inspection and make corresponding corrections if necessary to ensure that the product meets basic quality standards; Finished product inspection and packaging: basic dimensional accuracy inspection and surface quality inspection, rust prevention treatment and packaging preparation for warehousing or shipment to meet basic logistics and storage requirements; Comparative Example 2: Inner star wheel forming process without phosphorus saponification treatment A blank making process before forming an inner star wheel, the steps of which are as follows: Pre-selection and pre-treatment of bar materials: Select bars of appropriate diameter, perform ultrasonic cleaning and sandblasting to ensure that the surface roughness meets certain standards, and perform magnetic particle inspection to ensure the internal quality of the bars; Preforming: Preforming the bar material to improve the shape of the blank before forming so that it can adapt to the shape requirements of the mold cavity. The diameter and length of the reducer after preforming are determined through calculation and testing; Shot blasting: Use appropriate steel shot diameter, speed and time for shot blasting to ensure uniform surface roughness of the material in preparation for subsequent processes; Phosphorus saponification treatment: Omit the phosphorus saponification treatment step to simplify the process and reduce production time and cost; Extrusion molding: It is carried out without a phosphorus saponification film. The pressure and temperature control during the molding process are the same as those in the embodiment to ensure the molding quality; Post-forming inspection and correction: Check the size and shape and make corrections if necessary to ensure that the product meets the design requirements; Finished product inspection and packaging: dimensional accuracy inspection and surface quality inspection, rust prevention treatment and packaging are carried out in preparation for warehousing or shipment to ensure the integrity of the product during transportation and storage.

[0044] Table 1: Comprehensive comparison of product performance

[0045] By comparing the product performance data of the embodiments and the comparative examples, it can be clearly seen that the present solution has significant advantages in multiple key performance indicators. Examples 1, 2 and 3 all show good performance in terms of the adaptability of the rod diameter, the fine control of the surface roughness, the moderate selection of the hardness value, the extension of the die life, the improvement of the production efficiency, the optimization of the extrusion forming pressure and the strict control of the dimensional accuracy. In particular, Example 2 performs outstandingly in terms of hardness and die life, which may be due to the specific pretreatment and phosphorus saponification treatment steps in the present solution, which improve the toughness and wear resistance of the material.

[0046] Table 2: Comparison of process stability and product consistency

[0047] In terms of process stability and product consistency, Examples 1 and 2 show high stability in shot blasting uniformity, phosphate saponification film uniformity and extrusion stability. Example 1 performs best in dimensional consistency and hardness consistency, which may be due to the fine control of the preforming and extrusion processes in this scheme, which ensure the consistency of the product. Comparative Example 1 performs poorly in terms of surface defect rate and process adjustment frequency, showing low process stability and product consistency. Example 3 is slightly lower than Examples 1 and 2 in dimensional consistency and hardness consistency, but is still better than Comparative Examples 1 and 2, which further demonstrates the effectiveness of this scheme in improving process stability and product consistency.

[0048] Table 3: Comparison of inner star wheel manufacturing process performance

[0049] In terms of the manufacturing process performance of the inner star wheel, Example 2 performed best in terms of material yield strength and elongation, showing the superior performance of the material. Example 1 performed best in terms of dimensional change after heat treatment and energy consumption during forging, which may be attributed to the optimization of the heat treatment process in this scheme, which reduced dimensional changes and improved energy efficiency. The shortening of the maintenance cycle of the forging equipment, as shown in Examples 1 and 2, may be due to the more reasonable process flow in this scheme, which reduced equipment wear and failure rate. The improvement of the product surface finish and fatigue resistance, as shown in Examples 1 and 2, further proves the remarkable effectiveness of this scheme in improving product quality and reliability.

[0050] In summary, this solution uses a pre-forming process to accurately adjust the shape of the bar so that its two ends form large and small heads, thereby ensuring that the bar can be smoothly placed in the mold cavity; this design not only improves the adaptability of the bar to the mold cavity, but also reduces the adjustment and mold replacement time caused by size mismatch during the production process; in addition, by reducing the adjustment time of the bar in the mold cavity, the overall efficiency of the production line is improved, thereby increasing the output per unit time without adding additional equipment.

[0051] In addition, through the preforming process, the shape of the bar is optimized to adapt to the internal structure of the die cavity, which helps to distribute the pressure more evenly during the forging process; this uniform pressure distribution reduces local stress concentration on the die, thereby reducing the risk of die wear and damage; in addition, the uniformity of the preformed bar also helps to reduce uneven deformation during the forging process, further reducing the incidence of forging defects and improving the overall quality of the forgings.

[0052] By adjusting the shape of the blank before forming, the appearance defects that may occur during the forging process, such as folding and collapsed angles, are significantly reduced; this improvement is achieved by precisely controlling the shape and size of the bar head, ensuring a more uniform flow of material in the die cavity, thereby reducing defects caused by uneven material flow.

[0053] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0054] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A blanking process before forming an inner star wheel, characterized in that: The steps are as follows: S01. Pre-selection and pre-treatment of bar stock: Select bar stock with appropriate diameter according to the design requirements of the inner star wheel; pre-treat the bar stock, including cleaning and removing surface defects, to ensure the smooth progress of the subsequent forming process; S02. Preforming: Preforming the bar material to improve the shape of the blank before forming so that it can meet the shape requirements of the mold cavity; the diameter and length of the reducer after preforming are determined through calculation and testing to reduce the forming pressure and eliminate appearance defects; S03. Shot blasting: Shot blasting is performed on the preformed bar material to remove the oxide scale and impurities on the surface, and at the same time improve the surface roughness of the material to prepare for the subsequent phosphorus saponification treatment; S04. Phosphorus saponification treatment: The shot blasted bars are subjected to phosphorus saponification treatment to form a protective film to reduce friction and wear during forging and increase die life; S05 extrusion: the phosphorus saponified rod is placed in an extruder and formed into the desired inner star wheel shape by applying pressure; Monitor the pressure and temperature during the extrusion process to ensure the quality of the forming; S06. Inspection and correction after forming: Check the inner star wheel after extrusion forming to ensure that its size and shape meet the design requirements; If there are any defects, make necessary corrections to ensure that the forging has a flawless appearance; S07. Finished product inspection and packaging: Carry out final quality inspection on the corrected inner star wheel, including dimensional accuracy and surface quality; qualified products are cleaned, rust-proofed, and packaged for storage or shipment.

2. According to claim 1, a blank making process before forming the inner star wheel, characterized in that: In the step S01, the pretreatment of the rod material includes cleaning with an ultrasonic cleaner for at least 5 minutes to remove oil and dust on the surface, followed by sandblasting to remove the surface oxide layer to ensure that the surface roughness reaches Ra≤3.2μm.

3. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S02, the diameter and length of the large and small heads after preforming are determined by finite element simulation calculation, wherein the large head diameter D1 is 1.05 to 1.15 times the original bar diameter D0, and the length L1 is 0.9 to 1.1 times the original bar length L0.

4. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S03, the diameter of the steel shot used in the shot blasting treatment is 0.5 to 1.0 mm, the shot blasting speed is 60 to 80 m / s, and the shot blasting time is controlled at 2 to 3 minutes to ensure that the surface roughness of the material is uniform.

5. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S04, the concentration of the phosphorus saponification treatment solution is controlled at 5% to 10%, the treatment temperature is 60 to 80° C., and the treatment time is controlled at 5 to 10 minutes to form a uniform phosphorus saponification film.

6. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S05, the pressure during the extrusion process is controlled at 300 to 500 MPa, the temperature is controlled at 900 to 1100° C., and the extrusion speed is 0.5 to 1.5 m / min to ensure the precise forming of the inner star wheel shape.

7. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S07, the finished product inspection includes using a three-coordinate measuring machine to perform dimensional accuracy inspection with an inspection accuracy of ±0.02 mm, and using a roughness meter to perform surface quality inspection to ensure that the surface roughness Ra ≤ 1.6 μm. Qualified products are coated with anti-rust oil and vacuum packaged.

8. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S01, the pretreatment of the bar material also includes performing magnetic particle inspection to detect cracks or other discontinuities inside the bar material to ensure that the internal quality of the bar material meets the forming requirements.

9. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S03, the rod material is preheated after the shot blasting, and the preheating temperature is controlled at 400° C. to 500° C. to reduce the thermal shock during the phosphorus saponification treatment and improve the adhesion of the phosphorus saponification film.

10. The process for forming the inner star wheel before forming according to claim 1, characterized in that: In the step S06, the post-forming inspection and correction also includes testing the hardness of the inner star wheel, using a Rockwell hardness tester to measure the hardness value of the inner star wheel to ensure that the hardness value is within a specified range to meet the performance requirements of subsequent use.

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