Titanium alloy hot pressing method

Abstract

The application belongs to the technical field of titanium alloy processing of an aero-engine, and particularly relates to a titanium alloy hot pressing method, which provides a process of achieving a local heating effect by means of manufacturing transient current and heat transfer through an electrode, and solves the problems of cracks easily occurring in cold forming of titanium alloy materials and difference in coaxiality of two ends of a whole hot pressed nest.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of titanium alloy processing of an aero-engine, and particularly relates to a titanium alloy hot pressing method. BACKGROUND

[0002] The guide vane on the inlet casing is a titanium alloy vane, and the guide vane is composed of a vane, a V-shaped baffle, a clamping plate, a gasket and a rivet. The V-shaped baffle is pressed when hot forming, and there is a problem of different coaxialities of the two ends of the formed recess. After the guide vane is assembled with the clamping plate, the gasket and the V-shaped baffle and riveted, the rivet is subjected to shearing force, which may cause product quality problems. In actual processing, the baffle is directly riveted and stamped. However, the titanium alloy has a high risk of cracking in cold forming. Therefore, it is urgent to solve the problem of pre-riveting the recess before riveting the titanium alloy to reduce the deformation and cracking risk of the vane in forming. SUMMARY

[0003] Therefore, the application provides a process for achieving local heating effect by manufacturing instantaneous current and heat transfer through electrodes, which solves the problems of easy cracking in cold forming of titanium alloy materials and different coaxialities of the two ends of the whole hot pressing recess.

[0004] In order to achieve the above technical purposes, the application adopts the following specific technical scheme:

[0005] A titanium alloy hot pressing method is used for riveting recess processing of an inlet guide vane and a V-shaped baffle of a titanium alloy material of a casing, and includes the following steps:

[0006] S101: Assembling the V-shaped baffle to the guide vane, and drilling a preformed hole through both sides of the V-shaped baffle and the guide vane at the V-shaped baffle;

[0007] S102: Disassembling the V-shaped baffle from the guide vane, chamfering the preformed hole of the guide vane to form a hot pressing recess female mold;

[0008] S103: Reassembling the V-shaped baffle to the guide vane to ensure the coaxiality of the preformed hole;

[0009] S104: Setting a first electrode and a second electrode coaxial with the preformed hole at the upper and lower ends of the preformed hole; the first electrode and the second electrode form a hot pressing recess male mold;

[0010] S105: Making the first electrode and the second electrode contact the V-shaped baffle;

[0011] S106: Generating an instantaneous current between the first electrode and the second electrode while feeding the first electrode and the second electrode to the guide vane;

[0012] S107: stopping the feeding before the first electrode and the second electrode contact, and maintaining the instantaneous current for a preset time length.

[0013] Further, the material of the first electrode and the second electrode is 45# steel.

[0014] Further, the hot-pressing hole method is used to process rivet holes with a diameter of 2.7-3.3mm; the contact part of the first electrode and the second electrode with the V-shaped baffle is a circular surface, and the diameter of the circular surface is 1.9-2.1mm.

[0015] Further, the hot-pressing hole method is used to process rivet holes with a diameter of 3mm; the contact part of the first electrode and the second electrode with the V-shaped baffle is a circular surface, and the diameter of the circular surface is 2mm.

[0016] Further, the thickness of the two V-shaped baffles is 0.8mm.

[0017] The feeding pressure between the first electrode and the second electrode is 450-550psi; the temperature of the contact part of the first electrode and the second electrode with the V-shaped baffle is 500-650℃.

[0018] Further, the feeding pressure of the first electrode and the second electrode is 500psi.

[0019] Further, the feeding distance sum of the first electrode and the second electrode is 2.8-3mm, and the feeding time is 170-230ms.

[0020] Further, the feeding time of the first electrode and the second electrode is 200ms.

[0021] Further, the preset time length is 170-230ms.

[0022] Further, the preset time length is 200ms. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 It is a structure schematic diagram of the guide vane in the specific embodiment of the present application.

[0025] Figure 2 It is an assembly state schematic diagram of the guide vane and the V-shaped baffle in the specific embodiment of the present application.

[0026] Figure 3 Figure 1 is a schematic view of a hot-pressing female die according to the present application;

[0027] Figure 4 Figure 2 is a schematic view of a prefabricated hole in a coaxial state according to the present application;

[0028] Figure 5 Figure 3 is a schematic view of a feeding and holding state according to the present application;

[0029] Figure 6 Figure 4 is a schematic view of a rivet connected state according to the present application;

[0030] Wherein: 1, guide vane; 2, prefabricated hole; 3, first electrode; 4, second electrode; 5, rivet; 11, V-shaped baffle. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail below with reference to the drawings.

[0032] The above embodiments are only used to illustrate the present application, but not to limit it. Instead of the above embodiments, other embodiments obtained by those of ordinary skill in the art based on the above description, without creative effort, should be covered by the present application. Therefore, the true protection scope of the present application should be defined by the claims.

[0033] It is to be understood that the foregoing description is merely illustrative of various aspects of embodiments and that numerous other aspects will become apparent to those skilled in the art upon reading and understanding the specification. It is to be understood that any feature described in relation to any one aspect can be incorporated with any other aspect, unless otherwise expressly excluded. It is also to be understood that the use of relational terms, if any, such as first, second, top and bottom, and the like are used solely to distinguish one from another entity or action without necessarily implying a strict order or order of importance, except when a context clearly dictates otherwise or understood by those of ordinary skill in the art.

[0034] It is also necessary to note that the drawings provided in the following embodiments only schematically illustrate the basic concepts of the present application, and only show the components related to the present application, not the number, shape and size of the components when actually implemented. The actual implementation of each component may be a random change, and the component layout may be more complex.

[0035] In addition, in the following description, specific details are provided to facilitate a thorough understanding of examples. However, one skilled in the relevant art will understand that the aspects described can be practiced without these specific details.

[0036] In one embodiment of the present application, a titanium alloy hot pressing pocket method is provided for riveting pocket processing of titanium alloy material of a compressor inlet guide vane 1 and a V-shaped baffle, comprising the following steps:

[0037] S101: Assemble the V-shaped baffle to the guide vane 1, drill a preformed hole 2 through both sides of the V-shaped baffle 11 and the guide vane 1 at the V-shaped baffle 11; the result is as shown in Figure 2 、 5 ;

[0038] S102: Disassemble the V-shaped baffle from the guide vane 1, chamfer the preformed hole 2 of the guide vane 1 to form a hot pressing pocket female mold; the result is as shown in Figure 1 ;

[0039] S103: Assemble the V-shaped baffle 11 to the guide vane 1 again to ensure the coaxiality of the preformed hole 2; the result is as shown in Figure 3 ;

[0040] S104: Set a first electrode 3 and a second electrode 4 coaxial with the preformed hole 2 at the upper and lower ends of the preformed hole 2; the first electrode 3 and the second electrode 4 form a hot pressing pocket male mold;

[0041] S105: Make the first electrode 3 and the second electrode 4 contact the V-shaped baffle 11;

[0042] S106: Generate an instantaneous current between the first electrode 3 and the second electrode 4 while feeding the first electrode 3 and the second electrode 4 to the guide vane 1; the result is as shown in Figure 4 ;

[0043] S107: Stop the feeding before the first electrode 3 and the second electrode 4 contact, and maintain the instantaneous current for a predetermined period of time.

[0044] In this embodiment, in order to ensure that the first electrode 3 and the second electrode 4 do not contaminate the V-shaped baffle 11, the material of the first electrode 3 and the second electrode 4 is 45# steel.

[0045] In one embodiment, the hot press hole method is used to process rivet 5 with a diameter of 2.7-3.3mm; the contact part of the first electrode 3 and the second electrode 4 with the V-shaped baffle 11 is set as a circular surface, and the diameter of the circular surface is selected as 1.9-2.1mm.

[0046] In one embodiment, the hot press hole method is used to process rivet 5 with a diameter of 3mm; the diameter of the circular surface is 2mm. The rivet hole-diameter of the rivet hole in this embodiment is set differently from the traditional process, so that the performance of the transient current hot press hole process in this embodiment is better.

[0047] In this embodiment, the thickness of the V-shaped baffle 11 is 0.8mm; the feeding pressure between the first electrode 3 and the second electrode 4 is 450-550psi; and the temperature of the contact part of the first electrode 3 and the second electrode 4 with the V-shaped baffle 11 is 500-650℃. Here, the hot press hole process for the traditional 0.8mm V-shaped baffle 11 is set.

[0048] In this embodiment, the feeding pressure between the first electrode 3 and the second electrode 4 is 500psi.

[0049] In this embodiment, in order to ensure the transient nature of the press hole process, the feeding distance between the first electrode 3 and the second electrode 4 is 2.8-3mm, and the feeding time is 170-230 milliseconds, preferably 200 milliseconds.

[0050] In order to avoid the elastic rebound of the press hole point after the press hole, the holding state is as shown in Figure 3 , and the preset holding time of the heating is 170-230 milliseconds, preferably 200 milliseconds.

[0051] In this embodiment, the material of the titanium alloy guide vane 1 is TA21 (containing 95.97%-97.77% titanium, near industrial pure titanium), and the thickness t of the V-shaped baffle is 0.8mm, which belongs to the baffle type bending titanium alloy thin-walled sheet metal part, and the structure is as shown in Figure 1 , 2 .

[0052] V-shaped baffle 11 press hole process analysis: according to the product press hole size requirement, the theoretical analysis and calculation are required according to the material limit press hole coefficient, and the limit press hole coefficient K of the plane under the cold state is 0.24 according to the standard, then K=Hmax / d0(H is the press hole depth, d0is the press hole diameter), according to the press hole size requirement of this embodiment, H is 1.1

[0053] If the hot pressing recess is realized when the V-shaped baffle 11 is hot formed, the hot working is difficult to realize the coaxiality of the recess centers of two sides, when the baffle is separated from the mold, the baffle must be forced to open and separated from the mold, and there are manufacturing tolerance and assembly error in assembly, which causes quality problems such as deflection of rivet 5 after riveting, and skew of rivet 5 after riveting.

[0054] In the embodiment, the hot pressing recess process can be realized by using a spot welding machine, and two electrodes of the spot welding machine are replaced by 45 steel materials.

[0055] If the baffle is assembled on the mold for heating and pressing recess by designing a baffle pressing recess mold, in the actual processing process, the baffle is heated by the resistance wire in the mold, since the baffle is a 0.8 mm sheet metal part, the temperature of the baffle sharply decreases during pressing recess, and the required temperature of hot forming cannot be reached, and the hot pressing recess on the mold fails.

[0056] The embodiment provides a process of achieving local heating effect by means of manufacturing instantaneous current and heat transfer through electrodes, and solves the problems of cracks in cold forming of titanium alloy material and difference in coaxiality of recesses at two ends of the whole hot pressing recess.

[0057] After the pressing recess is completed, chamfering, hole expanding and deburring are performed on the pressing recess, and then the rivet 5 is riveted, and the result is as shown in Figure 6 .

[0058] The electrode material requires excellent electrical conductivity, and copper and its alloy materials are usually used. Since the blade material is titanium alloy, soft metal contaminates the titanium alloy, and the embodiment uses 45 steel parts as the material of the first electrode 3 and the second electrode 4.

[0059] The detection result of the test piece detection of the hot pressing recess part by using the hot pressing recess method of the embodiment shows that there is no heat affected change, no alpha layer, and the H content is less than 0.011%, which completely meets the process requirements.

[0060] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any change or replacement easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for hot pressing a titanium alloy, for riveting a pocket of a titanium alloy material of a casing inlet guide vane and a V-shaped baffle, characterized in that, The method comprises the following steps: S101: Assembling the V-shaped baffle to the guide vane, drilling a preformed hole through both sides of the V-shaped baffle and the guide vane; S102: Disassembling the V-shaped baffle from the guide vane, chamfering the preformed hole of the guide vane to form a hot-pressing nest female mold; S103: Reassembling the V-shaped baffle to the guide vane to ensure the coaxiality of the preformed hole; S104: Setting a first electrode and a second electrode coaxial with the preformed hole at the upper and lower ends of the preformed hole; the first electrode and the second electrode form a hot-pressing nest male mold; S105: Contacting the first electrode and the second electrode with the V-shaped baffle; S106: Generating an instantaneous current between the first electrode and the second electrode while feeding the first electrode and the second electrode to the guide vane; S107: Stopping the feeding before the first electrode and the second electrode contact, and maintaining the instantaneous current for a preset time length; The thickness of the two V-shaped baffles is 0.8 mm, the feeding pressure between the first electrode and the second electrode is 450-550 psi, and the temperature of the contact part of the first electrode and the second electrode with the V-shaped baffle is 500-650℃; The total feeding distance of the first electrode and the second electrode is 2.8-3 mm, and the feeding time is 170-230 milliseconds; The preset time length is 170-230 milliseconds.

2. The hot press-in pocket method of claim 1, wherein: The material of the first electrode and the second electrode is 45# steel.

3. The hot press-in pocket method of claim 2, wherein: The hot-pressing nest method is used to process rivet holes with a diameter of 2.7-3.3 mm, the contact part of the first electrode and the second electrode with the V-shaped baffle is a circular surface, and the diameter of the circular surface is 1.9-2.1 mm.

4. The hot press-in pocket method of claim 3, wherein: The hot-pressing nest method is used to process rivet holes with a diameter of 3 mm, the contact part of the first electrode and the second electrode with the V-shaped baffle is a circular surface, and the diameter of the circular surface is 2 mm.

5. The hot press-in pocket method of claim 4, wherein: The feeding pressure of the first electrode and the second electrode is 500 psi.

6. The hot press-in pocket method of claim 5, wherein: The feeding time of the first electrode and the second electrode is 200 milliseconds.

7. The hot press-in method according to claim 6, characterized in that: The preset time length is 200 milliseconds.

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