A method for preparing test specimens for composite solid-state welding process

Abstract

This invention relates to a method for preparing a composite solid-state welding process test piece, specifically including the following steps: Step 1: First, the welding surfaces of titanium alloy test pieces I and II are machined into flat surfaces. The two titanium alloy test pieces to be joined are placed in a diffusion welding furnace to complete the preparation of the diffusion weld joint. Step 2: The diffusion weld joint prepared in Step 1 is machined to the size of the simulated part, and linear friction welding is performed with the titanium alloy test block on a linear friction welding device to complete the preparation of the diffusion weld-friction weld joint; the linear friction weld in this step is arranged in a T-shape with the diffusion weld in Step 1. Step 3: The composite solid-state welding test block is machined into a composite solid-state process test piece according to the design drawing. This invention can realize effective fatigue test simulation of hollow blade integral bladed disks for diffusion welding and linear friction welding composite welding, verify the feasibility of diffusion welding and linear friction welding composite welding scheme, meet the needs of product research and development and production, and has broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and particularly relates to a method for preparing a composite solid-state welding process test piece, especially to solid-state welding of integral bladed disks, for use in the manufacture of integral bladed disk-type parts for aero-engines. Background Technology

[0002] Both diffusion welding and friction welding are solid-state joining methods. Solid-state joining does not require flux during the welding process; the weld joint is formed directly by the connection of the metals to be welded. The principle of diffusion welding lies in the inter-atomic diffusion of the interface metals under high temperature and pressure, forming symbiotic grains at the weld interface, ultimately connecting the metals into a whole. The principle of friction welding lies in the plastic state of the weld metal under friction, causing recrystallization and ultimately connecting the metals into a whole. Both technologies can be used in the manufacture of aero-engine parts. Diffusion welding is mainly used for connecting fixed components such as support plates, while friction welding is mainly used for connecting rotating components. Currently, the development of individual welding technologies is quite mature.

[0003] Chinese Patent (Publication No.: CN101367156A, Publication Date: February 18, 2009) discloses a linear friction welding method, comprising the following steps: setting the amplitude of the two weldments to a constant amplitude, and increasing the vibration frequency from a lower frequency to a higher frequency in the initial stage of friction; then, a constant frequency and constant amplitude friction stage, during which the vibration frequency and amplitude are constant; in the final stage of friction, the amplitude gradually decreases, and when the amplitude gradually drops to 0, causing the two weldments to return to their center position, upsetting pressure is applied to complete the welding; throughout the welding process, the friction pressure remains constant. Because the larger amplitude and lower frequency in the initial stage of friction can effectively mechanically clean and preheat the friction interface; in the middle and later stages of friction, the gradually decreasing amplitude makes the high-temperature range of the joint wider and more uniform, allowing the deformed metal to fully recover and recrystallize, eliminating residual stress in the welded joint, and improving the quality of the joint.

[0004] Chinese Patent (Publication No.: CN104551380A, Publication Date: April 29, 2015) CN201410811818.1 provides an integral bladed disk and its manufacturing method, including: (1) arranging and fixing all blades along the circumferential direction of the disk; (2) linearly friction welding all blades and the disk along the circumferential direction of the disk; and simultaneously applying a forging force along the axial direction of the disk to keep the blades in contact with the disk; (3) when the contact surface between the blades and the disk is heated to the metal plastic deformation temperature, increasing the forging force along the axial direction of the disk to fix the blades and the disk together, thereby obtaining a preform of the integral bladed disk; (4) post-processing the preform of step (3) to obtain the integral bladed disk. In the manufacturing method of the present invention, when the blades are welded to the bladed disk, the blades and the bladed disk move back and forth at high speed in the circumferential direction. Therefore, when the welding is terminated, no matter where the blades are at rest, the relative positional accuracy between the blades will not be affected. This greatly reduces the requirements for equipment and processes and improves the product yield.

[0005] Chinese Patent (Publication No.: CN203509338U, Publication Date: April 2, 2014) discloses a novel welding technology, specifically friction welding. The infrared preheating friction welding system includes a housing containing a friction welding fixture and a heating plate with heating wires arranged according to the contour of the contact surface of the workpiece. The heating plate is movably connected to the housing. The heating plate is connected to the housing via a rotating mechanism. The housing has an openable door, with the friction welding fixture located inside. The door has a glass window for observing the working status. The rotating mechanism is connected to and driven by a power mechanism, which in turn is connected to a control system to control the movement of the heating plate. By adding heating wires, the workpiece is heated, combining the heat generated by the heating wires with the heat generated by friction. This allows the contact surface of the workpiece to quickly reach or approach a molten state, solving the problems of impurities, cold slag, slow welding speed, and poor forming effect associated with welding relying solely on friction heat.

[0006] With the development of aviation technology, reasonable weight reduction is a trend in engine development, and materials and structure are two key aspects of weight reduction. Hollow blades made of titanium alloy can effectively achieve the goal of weight reduction. However, in the manufacturing of integral bladed disks with hollow blade structures, the connection between the hollow blades and the disk cannot be achieved through either diffusion welding or linear friction welding. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for preparing composite solid-state welding process test pieces, which solves the problem that traditional single solid-state welding methods, including diffusion welding and friction welding, cannot complete the connection between the blades and the disk of a hollow fan blade integral bladed disk. This makes the integral bladed disk part structure lighter and improves the specific strength and specific stiffness of the integral bladed disk part.

[0008] A method for preparing a composite solid-state welding process test specimen specifically includes the following steps:

[0009] Step 1: First, the welding surfaces of the two titanium alloy test pieces to be joined, namely titanium alloy test piece I and titanium alloy test piece II, are processed into flat surfaces. Then, the two titanium alloy test pieces are placed in a diffusion welding furnace to complete the preparation of the diffusion weld joint.

[0010] Step 2: The diffusion welded head prepared in Step 1 is processed to the size of the simulated part, and linear friction welding is performed with the titanium alloy test block on a linear friction welding equipment to complete the preparation of the diffusion weld-friction welded head;

[0011] Step 3: Process the composite solid phase welding test block into a composite solid phase process test piece according to the design drawing.

[0012] The titanium alloy specimens I and II are hollow sheet-like titanium alloys, while the titanium alloy block is a solid titanium alloy block.

[0013] The flatness in step 1 reaches 0.02 mm.

[0014] In the preparation of the diffusion welded joint in step 1, the diffusion welding furnace is heated to 800℃-900℃, a pressure of 2MPa-5MPa is applied, and the joint is held at that temperature for 2-3 hours before being removed from the furnace.

[0015] The welding parameters for linear friction welding in step 2 are: pressure 60MPa-100MPa, frequency 30Hz-60Hz, and amplitude 2mm-3mm.

[0016] The specific method for machining the diffusion weld head to the size of the simulated part in step 2 is as follows:

[0017] First, taking the plane where the diffusion weld is located as the plane of symmetry, remove material evenly on both sides of the diffusion weld head; take the plane of the diffusion weld head that is perpendicular to the diffusion weld as the welding surface of the linear friction weld. Stop processing when the length and width of the welding surface of the linear friction weld are the same as those of the titanium alloy test block, so that the welding surface of the diffusion weld head is the same size as the welding surface of the titanium alloy test block.

[0018] The linear friction weld in step 2 and the diffusion weld in step 1 are arranged in a T-shape.

[0019] The composite solid-state process test specimen in step 3 is divided into two parts: a vibration part and a clamping part. Titanium alloy specimen I and titanium alloy specimen II are the vibration part, and the titanium alloy specimen block is the fixing part. First, the clamping part is processed with the linear friction weld as the boundary. The processing dimensions are: height 55mm-57mm, width 49.9mm-50.1mm, and thickness 4.5mm-5.5mm. Then, the vibration part is processed with the diffusion weld as the center surface. The processing dimensions are: height 69mm-71mm, width 29mm-31mm, and thickness 25mm-27mm. The clamping part and the vibration part are connected by an arc.

[0020] The beneficial effects of this invention are:

[0021] This invention provides a method for preparing test specimens using a composite solid-state welding process. This method enables effective fatigue testing simulation of hollow blade integral bladed disks that are composite welded by diffusion welding and linear friction welding. It verifies the feasibility of the diffusion welding and linear friction welding scheme, and achieves high repeatability in part manufacturing. This method solves the manufacturing problem of hollow blade integral bladed disks that cannot be completed by traditional single solid-state welding methods, significantly improves the manufacturing accuracy of integral bladed disk parts, and increases the production efficiency and manufacturing qualification rate of integral bladed disk parts. It can meet the needs of product research and development and production and has broad application prospects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the diffusion welding head in Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the diffusion welding-friction welding joint in Embodiment 1 of the present invention;

[0024] Figure 3 This is a schematic diagram of the composite solid phase welding process test piece in Embodiment 1 of the present invention (wherein, Figure (a) is the front view and Figure (b) is the side view);

[0025] in,

[0026] 1-Titanium alloy specimen I, 2-Titanium alloy specimen II, 3-Titanium alloy specimen block, 4-Diffusion weld, 5-Linear friction weld. Detailed Implementation

[0027] To better explain and facilitate understanding of the present invention, the technical solution and effects of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] This embodiment provides a method for preparing a composite solid-state welding process test piece, specifically including the following steps:

[0030] Step 1: First, the welding surfaces of the two titanium alloy test pieces to be joined, namely titanium alloy test piece I1 and titanium alloy test piece II2, are machined to be flat, with a flatness of 0.02 mm. Titanium alloy test pieces I1 and II2 are then placed in a diffusion welding furnace, heated to approximately 900℃, subjected to a pressure of 2 MPa, and held at that temperature for 2 hours before being removed from the furnace, completing the preparation of the diffusion weld joint. Figure 1 As shown.

[0031] The titanium alloy specimens I1 and II2 are hollow sheet-like titanium alloys to simulate the structure of hollow blades, and the welds are located on the thickness side of the titanium alloy specimens I1 and II2.

[0032] Step 2: Machining the diffusion welded head prepared in Step 1 to the size of the simulated part. Specifically: First, using the plane where the diffusion weld is located as the plane of symmetry, uniformly remove material from both sides of the diffusion welded head formed by titanium alloy specimens I1 and II2. The surface of this diffusion welded head perpendicular to the diffusion weld is used as the welding surface for linear friction welding. Machining is stopped when the length and width of the linear friction welding surface are the same as those of the titanium alloy specimen 3, ensuring that the welding surface of the diffusion welded head has the same dimensions as the welding surface of the titanium alloy specimen 3. Then, linear friction welding is performed on the specimen 1 and specimen 2 assembly and specimen 3 on a linear friction welding device to complete the preparation of the diffusion weld-friction welded head. Figure 2 As shown.

[0033] The welding parameters are: pressure 100MPa, frequency 30Hz, and amplitude 3mm.

[0034] The titanium alloy test block 3 is a solid titanium alloy block to simulate the disk structure of an integral bladed disk.

[0035] The diffusion-friction weld joint has two welding processes: diffusion welding and friction welding. The linear friction weld 5 in this step and the diffusion weld 4 in step 1 are arranged in a T-shape.

[0036] Step 3: Fabricate the composite solid phase welding test block into a composite solid phase process test piece according to the design drawings:

[0037] The process test specimen consists of two parts: a vibration section and a clamping section. Titanium alloy specimens I1 and II2 constitute the vibration section, while titanium alloy specimen 3 constitutes the clamping section. First, the clamping section is machined along the linear friction weld 5, with dimensions of 56mm height × 50mm width × 5mm thickness. Then, the vibration section is machined along the diffusion weld 4 as the center plane, with dimensions of 70mm height × 30mm width × 26mm thickness. The clamping and vibration sections are transitioned by an arc, ensuring that the linear friction weld 5 is located at the intersection of the arc and the vibration section. Figure 3 As shown.

[0038] Results Analysis: The fatigue test specimens prepared using the above method can simulate the welded structure of a hollow blade integral bladed disk for fatigue testing. They can be used for mechanical testing of welded joints in hollow blade integral bladed disks, meeting the application requirements of part development. The method of this invention has excellent simulation effect for fatigue testing of composite solid-phase connection joints in hollow blade integral bladed disks, meeting the application requirements for rapid verification of key technologies.

[0039] Example 2

[0040] This embodiment provides a method for preparing a composite solid-state welding process test piece, specifically including the following steps:

[0041] Step 1: First, the welding surfaces of the two titanium alloy test pieces to be joined, namely titanium alloy test piece I1 and titanium alloy test piece II 2, are machined to be flat, with a flatness of 0.02 mm. Titanium alloy test pieces I1 and II 2 are then placed in a diffusion welding furnace, heated to approximately 900℃, subjected to a pressure of 5 MPa, and held at that temperature for 3 hours before being removed from the furnace, thus completing the preparation of the diffusion weld joint.

[0042] The titanium alloy specimens I1 and II2 are hollow sheet-like titanium alloys to simulate the structure of hollow blades, and the welds are located on the thickness side of the titanium alloy specimens I1 and II2.

[0043] Step 2: Machining the diffusion welded head prepared in Step 1 to the size of the simulated part. Specifically: First, using the plane where the diffusion weld is located as the plane of symmetry, uniformly remove material from both sides of the diffusion welded head formed by titanium alloy specimens I1 and II2. The surface of this diffusion welded head perpendicular to the diffusion weld is used as the welding surface for linear friction welding. Machining is stopped when the length and width of the linear friction welding surface are the same as those of the titanium alloy specimen 3, ensuring that the welding surface of the diffusion welded head has the same dimensions as the welding surface of the titanium alloy specimen 3. Then, linear friction welding is performed on the specimen 1 and specimen 2 assembly and specimen 3 on a linear friction welding device to complete the preparation of the diffusion weld-friction welded head. Figure 2 As shown.

[0044] The welding parameters are: pressure 80MPa, frequency 50Hz, and amplitude 2.5mm.

[0045] The titanium alloy test block 3 is a solid titanium alloy block to simulate the disk structure of an integral bladed disk.

[0046] This diffusion-friction weld joint incorporates both diffusion welding and friction welding processes. The linear friction weld in this step is arranged in a T-shape with the diffusion weld in step 1.

[0047] Step 3: Fabricate the composite solid phase welding test block into a composite solid phase process test piece according to the design drawings:

[0048] The process test specimen consists of two parts: a vibration section and a clamping section. Titanium alloy specimens I1 and II2 constitute the vibration section, while titanium alloy specimen 3 constitutes the clamping section. First, the clamping section is machined along the linear friction weld seam, with dimensions of 70mm × 30mm × 26mm. Then, the vibration section of the process test specimen is machined along the diffusion weld seam, with dimensions of 50mm × 56mm × 5mm. The clamping and vibration sections are transitioned with an arc, ensuring the linear friction weld seam is located at the intersection of the arc and the vibration section.

[0049] Results Analysis: The fatigue test specimens prepared using the above method can simulate the welded structure of a hollow blade integral bladed disk for fatigue testing. They can be used for mechanical testing of welded joints in hollow blade integral bladed disks, meeting the application requirements of part development. The method of this invention has excellent simulation effect for fatigue testing of composite solid-phase connection joints in hollow blade integral bladed disks, meeting the application requirements for rapid verification of key technologies.

Claims

1. A method for preparing a composite solid-state welding process test specimen, characterized in that, Specifically, the following steps are included: Step 1: First, the welding surfaces of the two titanium alloy test pieces to be joined, namely titanium alloy test piece I and titanium alloy test piece II, are processed into flat surfaces. Then, the two titanium alloy test pieces are placed in a diffusion welding furnace to complete the preparation of the diffusion weld joint. In the preparation of diffusion welded joints, the diffusion welding furnace is heated to 800℃-900℃, a pressure of 2MPa-5MPa is applied, and the joints are held at that temperature for 2-3 hours before being removed from the furnace. Step 2: The diffusion welded head prepared in Step 1 is processed to the size of the simulated part, and linear friction welding is performed with the titanium alloy test block on a linear friction welding equipment to complete the preparation of the diffusion weld-friction welded head; Step 3: Fabricate the composite solid phase welding test block into a composite solid phase process test piece according to the design drawings; The titanium alloy specimen I and titanium alloy specimen II are hollow sheet-like titanium alloys, while the titanium alloy block is a solid titanium alloy block. The linear friction weld in step 2 and the diffusion weld in step 1 are arranged in a T-shape.

2. The method for preparing a composite solid-state welding process test piece according to claim 1, characterized in that: In step 1, the flatness of the welding surface reaches 0.02 mm.

3. The method for preparing a composite solid-state welding process test specimen according to claim 1, characterized in that: The welding parameters for linear friction welding in step 2 are: pressure 60 MPa - 100 MPa, frequency 30 Hz - 60 Hz, and amplitude 2 mm - 3 mm.

4. The method for preparing a composite solid-state welding process test piece according to claim 1, characterized in that: The specific method for machining the diffusion weld head to the size of the simulated part in step 2 is as follows: First, taking the plane where the diffusion weld is located as the plane of symmetry, remove material evenly on both sides of the diffusion weld head; take the plane of the diffusion weld head that is perpendicular to the diffusion weld as the welding surface of the linear friction weld. Stop processing when the length and width of the welding surface of the linear friction weld are the same as those of the titanium alloy test block, so that the welding surface of the diffusion weld head is the same size as the welding surface of the titanium alloy test block.

5. The method for preparing a composite solid-state welding process test piece according to claim 1, characterized in that: The composite solid-state process test specimen in step 3 is divided into two parts: a vibration part and a clamping part. Titanium alloy specimen I and titanium alloy specimen II are the vibration part, and titanium alloy specimen block is the fixing part. First, the clamping part is processed with the linear friction weld as the boundary. The processing dimensions are: height 55 mm - 57 mm, width 49.9 mm - 50.1 mm, and thickness 4.5 mm - 5.5 mm. Then, the vibration part is processed with the diffusion weld as the center surface. The processing dimensions are: height 69 mm - 71 mm, width 29 mm - 31 mm, and thickness 25 mm - 27 mm. The clamping part and the vibration part are connected by an arc.

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