A processing method of a capsule-shaped flat tube thin-wall titanium alloy strut

Abstract

The application discloses a processing method of a capsule-shaped flat tube thin-wall titanium alloy support, which comprises the following steps: selecting a blank material type, designing and manufacturing a forming die, calculating the size of the blank material, assembling the die, forming the part and processing the shape. The titanium alloy round tube with the same cross section area perpendicular to the axial direction and the same wall thickness of the capsule-shaped flat tube thin-wall titanium alloy support part is selected as the blank material, and a positioning section is added outside the blank material, then the titanium alloy round tube is hot formed by cooperating with the forming die, the surface of the cooled part is subjected to the descaling treatment, and finally the final shape size is obtained by using the machining method. The forming processing method without welding seam is selected, the forming die is reliable and effective, and the size precision and the processing quality of the part can be effectively ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mechanical processing, and particularly relates to a processing method of a capsule-shaped flat-tube thin-wall titanium alloy support. BACKGROUND

[0002] The intermediate casing is an important component of an aero-engine, and connects components such as a fan and a high-pressure compressor. The thin-wall titanium alloy support plays a crucial role in the intermediate casing, and not only provides structural support for the intermediate casing, but also guides and optimizes airflow. A part structure diagram is shown in FIG. Figure 1

[0003] At present, the processing scheme of the thin-wall titanium alloy support is to first divide a titanium alloy plate into two halves to form a U-shaped half capsule, then cut and repair the U-shaped excess to form a capsule, then polish the weld after welding, and then ensure the part profile through heat shaping, and finally process the outer dimensions.

[0004] The above processing scheme has the following processing difficulties and hidden dangers:

[0005] (1) When removing the excess of the formed U-shaped part, it is difficult to ensure the consistency of the gap between the welding butt faces, resulting in unstable welding quality;

[0006] (2) The capsule-shaped flat-tube thin-wall titanium alloy support has a narrow inner cavity width (about 10 mm) and a length of about 200 mm. During welding, it is difficult to implement gas protection measures, and it is difficult to polish the capsule-shaped cavity after welding.

[0007] (3) Welding deformation requires heat shaping to ensure the part profile, which increases the processing time and the processing cost of the part, and prolongs the delivery cycle of the support.

[0008] Based on the above reasons, a processing method of a capsule-shaped flat-tube thin-wall titanium alloy support is needed to overcome the difficulties and hidden dangers listed in (1) to (3) and meet the quality requirements of the part shape and size precision. SUMMARY

[0009] The application aims to provide a processing method of a capsule-shaped flat-tube thin-wall titanium alloy support, which selects a forming processing method without welds, uses reliable and effective forming dies, and effectively ensures the size precision and processing quality of the part.

[0010] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0011] A processing method of a capsule-shaped flat-tube thin-wall titanium alloy support, comprising:

[0012] ​The titanium alloy round pipe with the same wall thickness and cross-sectional area perpendicular to the axial direction as the wall thickness of the capsule-shaped flat pipe thin-wall titanium alloy support part is selected as the blank material;

[0013] The forming die is designed and manufactured according to the size and shape of the capsule-shaped flat pipe thin-wall titanium alloy support part. The forming die mainly comprises an upper die plate, a lower die plate, an upper die and a lower die. The upper cavity of the upper die comprises a first U-shaped forming cavity and a first positioning cavity. The lower cavity of the lower die comprises a second U-shaped forming cavity and a second positioning cavity. The parting surface of the first U-shaped forming cavity and the second U-shaped forming cavity corresponds to the bisector of the axial line of the capsule-shaped flat pipe thin-wall titanium alloy support. The first positioning cavity and the second positioning cavity form a cylindrical cavity.

[0014] The size of the blank material is calculated based on the axial length and wall thickness of the capsule-shaped flat pipe thin-wall titanium alloy support part. The axial length and wall thickness of the titanium alloy round pipe blank material are consistent with the axial length and wall thickness of the capsule-shaped flat pipe thin-wall titanium alloy support part. According to the principle of constant volume, the blanking size of the titanium alloy round pipe blank material is calculated, including the inner diameter ΦD2 and the outer diameter ΦD1. An additional positioning length L2 is added to the axial length of the titanium alloy round pipe blank material.

[0015] The die is assembled. The lower die is first installed and fixed on the lower die plate, and then the lower die plate is fixed on the lower platform of the forming machine. The upper die is then installed and fixed on the upper die plate, and then the upper die plate is fixed on the upper platform of the forming machine.

[0016] The formed part is obtained by placing the titanium alloy round pipe blank material into the lower die, with a section corresponding to the positioning length L2 placed in the second positioning cavity of the lower die of the forming die, and the remaining part located in the second U-shaped forming cavity. The titanium alloy round pipe blank material is heated and the forming die is preheated. The temperature is raised to the hot forming temperature. The upper die and the lower die are combined by moving the press equipment downward to apply pressure and hot forming is performed. After a period of temperature and pressure preservation, the capsule-shaped flat pipe thin-wall titanium alloy support is obtained after cooling and opening the die. The surface of the cooled capsule-shaped flat pipe thin-wall titanium alloy support is treated.

[0017] The shape is processed according to the required size of the capsule-shaped flat pipe thin-wall titanium alloy support part until the required size is obtained.

[0018] As an alternative, when selecting the blank material, a titanium alloy bar or a titanium alloy round pipe with inconsistent diameters is used to remove excess material by turning the inner and outer circles to process a titanium alloy round pipe with the same wall thickness and cross-sectional area perpendicular to the axial direction as the blank material.

[0019] Alternatively, the first positioning cavity is designed and manufactured to have a larger volume than the second positioning cavity.

[0020] Alternatively, the first positioning cavity and the second positioning cavity form a cylindrical cavity with an inner diameter equal to the outer diameter ΦD1 of the titanium alloy round tube blank material.

[0021] Alternatively, the first U-shaped forming cavity and the first positioning cavity have a length sum greater than the sum of the axial length and the positioning length L2 of the capsule-shaped flat tube thin-walled titanium alloy support part.

[0022] Alternatively, after the assembly mold and before the forming part, the upper mold and the lower mold in the forming mold are coated with boron nitride protective paint, and the titanium alloy round tube blank material is subjected to surface cleaning treatment and boron nitride protective paint coating.

[0023] Alternatively, during the forming part, the preheating temperature of the forming mold is 70% to 80% of the heating temperature of the titanium alloy round tube blank material.

[0024] Alternatively, during the forming part, the hot forming temperature is 870℃±10℃, the downward movement of the press equipment to apply pressure is 1.5 to 6T, and the holding time is 16 to 20 minutes, and then the part and the forming mold are naturally cooled.

[0025] Alternatively, during the forming part, the surface treatment of the cooled capsule-shaped flat tube thin-walled titanium alloy support includes first removing the surface oxidation layer by sandblasting, and then removing the surface oxidation layer by pickling.

[0026] The processing scheme of the capsule-shaped flat tube thin-walled titanium alloy support provided by the present application does not need to go through welding, polishing, heat shaping and other processes compared with the traditional scheme, so that the product processed by the present application does not have welding defects such as undercut, welding protrusion, slag inclusion and gas hole, and there is no problem of weld cracking during forming. The processing method of the present application is more reliable, and the consistency of the processed parts is better and the quality is higher. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the capsule-shaped flat tube thin-walled titanium alloy support structure in the present application;

[0028] Figure 2 is a schematic diagram of the forming mold structure in the present application;

[0029] Figure 3 is a schematic diagram of the titanium alloy round tube blank material in the present application;

[0030] Figure 4is a schematic diagram of a part formed in the present application;

[0031] In the figure, 1 is an upper die plate, 2 is a lower die plate, 3 is an upper die, and 4 is a lower die. DETAILED DESCRIPTION

[0032] The present application will be further described below in conjunction with specific examples, but should not be understood as limiting the scope of the subject matter described herein to the following examples. Any modifications, substitutions and changes made according to ordinary technical knowledge and common practices in the art without departing from the technical ideas of the present application are included in the scope of the present application.

[0033] The basic idea of the capsule-shaped flat tube thin-walled titanium alloy strut machining method of the present application is as follows:

[0034] Step 1: Select the type of blank material. When titanium alloy struts are machined from sheet metal, they need to be machined by welding. Welding can cause problems such as unstable appearance quality and welding quality. Therefore, if welding machining is to be avoided, a round tube with the same thickness as the part material needs to be used.

[0035] Step 2: Forming die design and manufacturing, as shown in Figure 2 According to the size and shape requirements of the titanium alloy strut, the forming die structure is designed and manufactured. The die is generally composed of an upper die plate 1, a lower die plate 2, an upper die 3 and a lower die 4. The forming cavities of the upper die 3 and the lower die 4 are split into two cavities according to the horizontal bisector of the C-C cross section. Figure 1

[0036] Step 3: Calculate the blank size, as shown in Figure 3 According to the principle of constant volume of struts with the same length, the inner and outer diameters of the blank round tube are calculated to be ΦD2 and ΦD1, respectively, the bottom area of the blank round tube is S1, and the length is L1.

[0037] Step 4: Assemble the die operation. First, install and fix the lower die 4 on the lower die plate 2, then fix the lower die plate 2 on the lower platform of the forming machine; then install and fix the upper die 3 on the upper die plate 1, and then fix the upper die plate 1 on the upper platform of the forming machine;

[0038] Step 5: Forming parts. Place the L2 section in the pre-processed blank round tube L1 in the pre-processed die lower die 4 clamping positioning half slot ΦD1, heat the blank round tube and preheat the die, heat to hot forming temperature 870℃±10℃, then move downward to apply pressure to complete the hot forming of the upper die 3 and the lower die 4, and perform surface treatment on the cooled flat tube;

[0039] Step 6: as shown in Figure 4 ​According to the required size of the part, the shape of the part is processed, and the excess shape size is removed by cutting or other machining methods.

[0040] Further, in step 1, the blank material types include plates, bars, pipes, and strips, etc. In order to avoid welding during the processing of titanium alloy struts, thin-walled pipes with the same wall thickness and bottom area (here, the bottom area refers to the cross-sectional area perpendicular to the axis direction of the pipe) are preferably used for processing. In addition, bars or round pipes with inconsistent diameters can be selected to remove excess material by turning the inner and outer circles to process round pipes with the same wall thickness and bottom area as the struts.

[0041] Further, in step 2, the length L2 of the cavity in the lower die 3 of the forming die structure is used for clamping and positioning the blank round pipe. The diameter at the clamping and positioning position is the same as the diameter of the blank round pipe, i.e. ΦD1. This clamping and positioning allows the round pipe to be located in the center of the capsule-shaped groove, and when the press machine applies pressure downward, the round pipe can be uniformly deformed into a flat pipe at both ends of the capsule-shaped groove. At the same time, the length of the forming surface of the forming die should be ≥L1 to ensure that the part is fully processed in shape during forming.

[0042] Further, in step 3, the length L1 of the blank round pipe satisfies the condition that the wall thickness is equal to that of the strut, i.e. (ΦD1-ΦD2) / 2. The bottom area S1 of the blank round pipe should be equal to the bottom area S of the strut, i.e. S1=S. The length L for processing the part and the length L2 for clamping and positioning are used, and the length of the blank round pipe is L2+L=L1.

[0043] Further, in step 5, the pre-processed blank round pipe and the forming die are cleaned. Organic solvents are used to remove oil stains, impurities, etc. on the surface of the round pipe and the die, and boron nitride protective paint is brushed on the outer circle of the blank round pipe and the forming die, and then naturally dried at room temperature.

[0044] Further, the preheating treatment of the forming die is to preheat the forming die while heating the round pipe to reduce the temperature difference between the round pipe and the forming die, and to prevent defects such as cold separation during forming. The preheating temperature of the forming die is 70% to 80% of the heating temperature of the round pipe.

[0045] Further, in step 5, the hot forming temperature is 870℃±10℃, the equipment pressure is 1.5-6T (tons), and the holding time is 16-20min. Then, the part and the forming die are naturally cooled.

[0046] Further, in step 5, the surface treatment is to treat the surface of the formed flat pipe. First, sandblasting is used to remove the thick oxide layer on the surface of the flat pipe, and then acid pickling is performed to accurately remove the oxide layer on the surface of the flat pipe to ensure the surface roughness of the finished product.

[0047] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method of processing a capsule-shaped, flat-tubular thin-walled titanium alloy strut, characterized by, The application relates to a capsule-shaped thin-wall titanium alloy strut part forming method. The capsule-shaped thin-wall titanium alloy strut part is formed by the following steps: selecting a blank material type, adopting a titanium alloy round pipe with the same wall thickness and the same cross-section area perpendicular to the axial direction as the capsule-shaped thin-wall titanium alloy strut part as the blank material; designing and manufacturing a forming die according to the size and shape of the capsule-shaped thin-wall titanium alloy strut part; the forming die is mainly composed of an upper die plate (1), a lower die plate (2), an upper die (3) and a lower die (4), wherein the upper cavity of the upper die (3) comprises a first U-shaped forming cavity and a first positioning cavity, the lower cavity of the lower die (4) comprises a second U-shaped forming cavity and a second positioning cavity, the parting surface of the first U-shaped forming cavity and the second U-shaped forming cavity corresponds to the bisector of the axial line of the capsule-shaped thin-wall titanium alloy strut, and the first positioning cavity and the second positioning cavity form a cylindrical cavity; when the forming die is designed and manufactured, the inner diameter of the cylindrical cavity formed by the first positioning cavity and the second positioning cavity is equal to the outer diameter PhiD1 of the titanium alloy round pipe blank material; calculating the size of the blank material, taking the axial length and the wall thickness of the capsule-shaped thin-wall titanium alloy strut part as the basis, taking the axial length and the wall thickness as the same as the axial length and the wall thickness of the capsule-shaped thin-wall titanium alloy strut part, calculating the blanking size of the titanium alloy round pipe blank material according to the principle of volume invariance, including the inner diameter PhiD2 and the outer diameter PhiD1, and additionally increasing a positioning length L2 on the basis of the axial length of the titanium alloy round pipe blank material; assembling the die; first, the lower die (4) is assembled and fixed on the lower die plate (2), then the lower die plate (2) is fixed on the lower platform of a forming machine tool, then the upper die (3) is assembled and fixed on the upper die plate (1), and then the upper die plate (1) is fixed on the upper platform of the forming machine tool; forming the part; the titanium alloy round pipe blank material is placed in the lower die (4), a section corresponding to the positioning length L2 of the titanium alloy round pipe blank material is placed in the second positioning cavity of the lower die (4) of the forming die, the remaining part is located in the second U-shaped forming cavity, the titanium alloy round pipe blank material is heated and the forming die is preheated, the temperature is raised to the hot forming temperature, then the die is closed by moving downwardly through a press equipment to complete the hot forming of the upper die (3) and the lower die (4), the temperature is kept for a period of time, then the die is opened after cooling to obtain the capsule-shaped thin-wall titanium alloy strut, and the surface of the capsule-shaped thin-wall titanium alloy strut after cooling is treated; when the part is formed, the preheating temperature of the forming die is 70%-80% of the heating temperature of the titanium alloy round pipe blank material; and the shape is processed according to the required size of the capsule-shaped thin-wall titanium alloy strut part drawing until the design requirement size is obtained. When the blank material type is selected, a titanium alloy bar or titanium alloy round pipes with inconsistent diameters are processed by turning to remove the excess material, and the titanium alloy round pipes with the same wall thickness and the same cross-section area perpendicular to the axial direction are processed as the blank material. When the forming die is designed and manufactured, the volume of the first positioning cavity is greater than that of the second positioning cavity. ​ ​ ​ ​ ​ 2. The processing method of a capsule-shaped flat tube thin-walled titanium alloy support column according to claim 1, characterized in that: ​ 3. The processing method of a capsule-shaped flat tube thin-walled titanium alloy support column according to claim 1, characterized in that: ​ 4. The processing method of a capsule-shaped flat tube thin-walled titanium alloy support column according to claim 1, characterized in that: The sum of the length of the first U-shaped forming cavity and the first positioning cavity and the sum of the length of the second U-shaped forming cavity and the second positioning cavity is greater than the sum of the axial length and the positioning length L2 of the capsule-shaped flat tube thin-walled titanium alloy support part.

5. The processing method of a capsule-shaped flat tube thin-walled titanium alloy support column according to claim 1, characterized in that: Before the assembly mold and the formed part, the upper die (3) and the lower die (4) in the forming mold are coated with boron nitride protective paint, and the titanium alloy round tube blank material is subjected to surface cleaning treatment and boron nitride protective paint coating.

6. The method of claim 1, wherein: the capsule-shaped, flat-tubular thin-walled titanium alloy strut is formed by: providing a titanium alloy tube having a first end, a second end, and a hollow interior; and forming the first end and the second end into a flat-tubular shape. When the part is formed, the hot forming temperature is 870℃±10℃, the press equipment moves downward to apply a pressure of 1.5-6T, and the holding time is 16-20min, and then the part and the forming mold are naturally cooled.

7. The processing method of a capsule-shaped flat tube thin-walled titanium alloy support column according to claim 1, characterized in that: When the part is formed, the surface treatment of the cooled capsule-shaped flat tube thin-walled titanium alloy support includes first removing the surface oxide layer by sandblasting, and then removing the surface oxide layer by pickling.

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