Forging forming method for titanium alloy blade

Abstract

The invention discloses a titanium alloy blade forging forming method which is characterized in that two working procedures of extrusion blank making and finish forging forming are adopted, firstly, the shape and the size of an extrusion blank are designed, then an extrusion die is designed, and the extrusion die is manufactured; producing an extrusion blank; the finish forging process is carried out after the extrusion process, qualified titanium alloy blade forgings are forged, use of part of process dies is reduced, the production cycle is shortened, and the cost is reduced. The method is mainly used for forging and forming the titanium alloy blade of the aero-engine.

Description

Technical Field

[0001] The present invention relates to a manufacturing method of a blade, in particular to a forging forming method of a titanium alloy blade. Background Art

[0002] The blade is a key part of an aeroengine, and its manufacturing quantity accounts for about one-third of the whole engine. The special structural composition and working principle of the engine put forward high requirements for the performance of the blade. At the same time, the temperature, air flow and pressure in the engine affect the service condition of the blade. Due to the requirements of aerodynamics, generally, the blade presents a complex curved surface structure, which brings difficulties to the manufacturing process.

[0003] The traditional forging forming methods of titanium alloy blade forgings include four processes: rod extrusion, upsetting, pre-forging and finish-forging. Special molds need to be designed for each process. At the same time, multiple auxiliary processes, such as grinding, sandblasting, corrosion, etc., need to follow each main process. The traditional process method requires a large number of toolings and has a long production cycle. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a forging forming method of a titanium alloy blade. By adopting the methods of extrusion blanking and finish-forging forming, qualified titanium alloy blade forgings are forged, the use of molds in some processes is reduced, the production cycle is shortened, and the cost is reduced.

[0005] To solve the above technical problem, the forging forming method of the titanium alloy blade described in the present invention includes the following steps in its technical solution:

[0006] Extrusion blanking: Design the shape and dimensions of the extrusion blank. According to the shape and dimensions of the titanium alloy blade forging, and based on the requirements of the deformation amount during the final forging process, calculate the dimensions of the square tenon of the extrusion blank and the dimensions of the two convex arc surfaces of the blade body of the extrusion blank. The connection between the blade body and the tenon is rounded. Design the shape and dimensions of the extrusion blank; Design the extrusion die. The extrusion die includes a left half die, a right half die, and a punch. According to the shape and dimensions of the extrusion blank, design the shapes and dimensions of the left half die and the right half die. The height of the tenon part of the left half die and the right half die is 10 mm more than the height of the titanium alloy bar; The extrusion die is equipped with an extrusion die sleeve, and the extrusion die sleeve is provided with an adjustable tightening mechanism; Manufacture the extrusion die. It is required that the roughness of the cavities of the left half die and the right half die is above 3.2, and the roughness of the extrusion forming parts of the left half die and the right half die is above 1.6; Produce the extrusion blank. The equipment used for production is a press. The press is equipped with an ejection device. After coating the surface of the titanium alloy bar with a special glass lubricant for titanium alloy, heat the titanium alloy bar to 20 - 40 °C below the titanium alloy phase transformation point and keep it warm for 20 - 30 minutes; Preheat the extrusion die to 200 - 300 °C. Place the left half die and the right half die into the extrusion die sleeve, and place the titanium alloy bar into the extrusion die. The press drives the punch to drop. After 10 mm of the blade body of the extrusion blank is formed, adjust the adjustable tightening mechanism of the extrusion die sleeve to make the left half die and the right half die each retreat 0.5 mm outward in the horizontal direction so that the punch can continue to drop and the subsequent titanium alloy can flow smoothly; The punch drops to the height dimension required for the tenon of the extrusion blank and stops. Then the punch rises, and the ejection device ejects the left half die and the right half die out of the extrusion die sleeve. The left half die and the right half die separate naturally, and the extrusion blank is taken out;

[0007] Final forging: After cleaning the extrusion blank, coat it with a special glass lubricant for titanium alloy. Heat the extrusion blank to 20 - 40 °C below the titanium alloy phase transformation point and keep it warm for 10 - 20 minutes; Preheat the final forging die to 200 - 300 °C and install the final forging die into the final forging die sleeve; The final forging process is carried out using a press. Place the extrusion blank in the lower die of the final forging die, and the press drives the final forging; The upper die of the die drops, contacts the extrusion blank and continues to move downward, and stops after reaching the dimensions of the final forging.

[0008] Preferably, the punch is installed on the press through a punch die sleeve. When producing the extrusion blank, ensure the tenon height by controlling the precise dimension of the press drop and setting gaskets between the punch and the punch die sleeve.

[0009] Preferably, in the method for forging and forming the titanium alloy blade, the material of the extrusion die is preferably 4Cr5W2VSi.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The forging and forming method of the titanium alloy blade described in the present invention forges the titanium alloy blade forging by using two processes of extrusion blanking and finish forging. Qualified forgings are produced through two sets of toolings and a relatively short forging process. Compared with the traditional process that uses four processes of extrusion rod, upsetting, pre-forging and finish forging, the present invention can save 50% of the die design, manufacturing cycle and cost. At the same time, due to the reduction of auxiliary processes, the production cycle and cost of the forging process can be shortened. The forging and forming method of the present invention has higher production efficiency and is convenient for large-scale automated production.

[0012] In the extrusion process of the present invention, the shape and size of the extruded blank are designed very excellently. First, the shape is simple. The extruded blank only includes a square tenon and a blade body with only two convex arc surfaces. Second, the size is reasonable. The size of the square tenon of the extruded blank and the sizes of the two convex arc surfaces of the blade body of the extruded blank are calculated according to the shape and size of the titanium alloy blade forging and the requirements of the deformation amount in the finish forging process. Therefore, it is very reasonable, and the auxiliary processes in the subsequent processing are correspondingly reduced, and there will be no waste of raw materials and manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of the extruded blank.

[0014] Figure 2 is a schematic structural diagram of the titanium alloy blade forging. DETAILED DESCRIPTION OF THE INVENTION

[0015] To implement the low-stress forming method of the titanium alloy special-shaped ring part described in the present invention, equipment such as a forging heating furnace, a press, a ring rolling mill, and a manipulator need to be provided. The following takes the titanium alloy with the grade of TC4 as an example to detail the specific implementation manner of this method:

[0016] The main chemical element contents (weight percentages) of this alloy are as follows: the Al content is 5.5% - 6.8%, the V content is 3.5% - 4.5%, the Fe content is ≤ 0.30%, the C content is ≤ 0.10%, the N content is ≤ 0.05%, the H content is ≤ 0.015%, the O content is ≤ 0.20%, the content of other elements is ≤ 0.10% for each single element and ≤ 0.40% in total, and the balance is Ti.

[0017] The steps of this method are as follows:

[0018] As Figure 1 and Figure 2 shown, design the shape and size of the extruded blank. According to the shape and size of the titanium alloy blade forging, and based on the requirements of the deformation amount in the finish forging process, calculate the size of the square tenon 1 of the extruded blank and the sizes of the two convex arc surfaces of the blade body 2 of the extruded blank. The connection between the blade body 2 and the tenon 1 is rounded, and design the shape and size of the extruded blank 6;

[0019] Design an extrusion die. The extrusion die includes a left half die, a right half die and a punch. According to the shape and size of the extrusion blank, design the shapes and sizes of the left half die and the right half die. The height of the tenon part of the left half die and the right half die is 10 mm more than the height of the titanium alloy bar stock. The extrusion die is equipped with an extrusion die sleeve, and the extrusion die sleeve is provided with an adjustable tightening mechanism.

[0020] Manufacture the extrusion die. It is required that the roughness of the cavities of the left half die and the right half die is above 3.2, and the roughness of the extrusion forming parts of the left half die and the right half die is above 1.6.

[0021] Produce the extrusion blank. The equipment used for production is a press, and the press is equipped with an ejection device. After coating the surface of the titanium alloy bar stock with a special glass lubricant for titanium alloy, heat the titanium alloy bar stock to 30 °C below the phase transition point of titanium alloy and keep it warm for 20 minutes. Preheat the extrusion die to 200 °C, place the left half die and the right half die into the extrusion die sleeve, place the titanium alloy bar stock into the extrusion die, the press drives the punch to drop. After the blade body 2 of the extrusion blank is formed by 10 mm, adjust the adjustable tightening mechanism of the extrusion die sleeve to make the left half die and the right half die withdraw 0.5 mm outward in the horizontal direction respectively, so that the punch can continue to drop and the subsequent titanium alloy can flow freely. The punch drops to the height dimension required for the tenon 1 of the extrusion blank and stops, then the punch rises, and the ejection device ejects the left half die and the right half die out of the extrusion die sleeve, the left half die and the right half die are separated naturally, and the extrusion blank is taken out.

[0022] After cleaning the extrusion blank, coat it with a special glass lubricant for titanium alloy, heat the extrusion blank to 30 °C below the phase transition point of titanium alloy and keep it warm for 10 minutes. Preheat the finish forging die to 200 °C and install the finish forging die into the finish forging die sleeve. The finish forging process is carried out by a press. Place the extrusion blank in the lower die of the finish forging die, the press drives the upper die of the finish forging die to drop, contact with the extrusion blank and continue to move downward, and stop after reaching the size of the finish forging part.

Claims

1. A forging method for titanium alloy blades, characterized in that, The method includes the following steps: Extrusion blanking: Design the shape and size of the extrusion blank. According to the shape and size of the titanium alloy blade forging, and based on the requirements of the deformation amount during the finish forging process, calculate the size of the square tenon of the extrusion blank and the sizes of the two convex arc surfaces of the blade body of the extrusion blank. The connection between the blade body and the tenon is rounded. Design the shape and size of the extrusion blank. Design the extrusion die. The extrusion die includes a left half die, a right half die and a punch. According to the shape and size of the extrusion blank, design the shapes and sizes of the left half die and the right half die. The height of the tenon part of the left half die and the right half die is 10 mm more than the height of the titanium alloy bar stock. The extrusion die is equipped with an extrusion die sleeve, and the extrusion die sleeve is provided with an adjustable tightening mechanism. Manufacture the extrusion die. It is required that the roughness of the cavities of the left half die and the right half die is above 3.2, and the roughness of the extrusion forming parts of the left half die and the right half die is above 1.

6. Produce the extrusion blank. The equipment used for production is a press, and the press is provided with an ejection device. After coating the surface of the titanium alloy bar stock with a special glass lubricant for titanium alloy, heat the titanium alloy bar stock to 20 - 40 °C below the phase transition point of titanium alloy and keep it warm for 20 - 30 minutes. Preheat the extrusion die to 200 - 300 °C. Place the left half die and the right half die into the extrusion die sleeve, and place the titanium alloy bar stock into the extrusion die. The press drives the punch to drop. After 10 mm of the blade body of the extrusion blank is formed, adjust the adjustable tightening mechanism of the extrusion die sleeve to make the left half die and the right half die withdraw 0.5 mm outward in the horizontal direction respectively, so that the punch can continue to drop and the subsequent titanium alloy can flow smoothly. The punch drops to the height dimension required for the tenon of the extrusion blank and stops. Then the punch rises, and the ejection device ejects the left half die and the right half die out of the extrusion die sleeve. The left half die and the right half die are naturally separated, and the extrusion blank is taken out. Finish forging: After cleaning the extrusion blank, coat it with a special glass lubricant for titanium alloy, heat the extrusion blank to 20 - 40 °C below the phase transition point of titanium alloy and keep it warm for 10 - 20 minutes. Preheat the finish forging die to 200 - 300 °C, and install the finish forging die into the finish forging die sleeve. The finish forging process is carried out using a press. Place the extrusion blank in the lower die of the finish forging die, and the press drives the finish forging. The upper die of the die drops, contacts the extrusion blank and continues to move downward, and stops after reaching the size of the finish forging.

2. The titanium alloy blade forging forming method according to claim 1, characterized in that The punch is installed on the press through a punch die sleeve. When producing the extrusion blank, the accurate size of the press drop is controlled and gaskets are set between the punch and the punch die sleeve to ensure the tenon height.

3. The titanium alloy blade forging method according to claim 1, characterized in that, In the method for forging and forming the titanium alloy blade, the material of the extrusion die is preferably 4Cr5W2VSi.

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