阅读说明：本技术 厚大变截面Ti-6242合金整体叶盘锻件的制备方法 (Preparation method of thick and large variable-section Ti-6242 alloy blisk forging ) 是由 李晓强 王周田 张昕 邓肯 张森峰 于 2019-11-05 设计创作，主要内容包括：本发明公开了一种厚大变截面Ti-6242合金整体叶盘锻件的制备方法,包括超声波检测满足技术标准要求的棒料实际噪声水平；根据锻件验收标准所要求的超声波检测噪声确定中间坯的理论超声波检测噪声；根据中间坯的理论超声波检测噪声和棒料实际的超声波检测噪声的差值,并结合每镦拔一次锻件噪声的降低值,计算改锻火次,制定改锻工艺,改锻得到中间坯；对中间坯进行模锻,得到锻件毛坯；对锻件毛坯进行粗加工,然后热处理。本方法能够得到质量稳定、可靠的厚大变截面Ti-6242合金整体叶盘锻件,中间坯制备方法、锻造工艺参数范围、锻件设计原则、模锻件结构调整方案等工艺过程设计明确、可控,从而能够推广应用到实际生产中。(The invention discloses a preparation method of a thick and large variable cross-section Ti-6242 alloy blisk forging, which comprises the following steps of detecting the actual noise level of a bar material meeting the technical standard requirement by ultrasonic waves; determining theoretical ultrasonic detection noise of the intermediate blank according to the ultrasonic detection noise required by the forge piece acceptance standard; calculating the forging-modifying heat according to the difference value of theoretical ultrasonic detection noise of the intermediate billet and actual ultrasonic detection noise of the bar material and the reduction value of the forging noise of each upsetting and drawing, formulating a forging-modifying process, and modifying forging to obtain an intermediate billet; die forging is carried out on the intermediate blank to obtain a forging blank; and (4) roughly processing the forging blank and then carrying out heat treatment. The method can obtain the thick and large variable cross-section Ti-6242 alloy blisk forge piece with stable and reliable quality, and the intermediate blank preparation method, the forging process parameter range, the forge piece design principle, the die forge piece structure adjustment scheme and other process designs are clear and controllable, so that the method can be popularized and applied to actual production.)

1. The preparation method of the thick and large variable cross-section Ti-6242 alloy blisk forging piece is characterized by comprising the following steps

Carrying out ultrasonic detection on the bar stock meeting the technical requirements to obtain the actual ultrasonic detection noise of the bar stock;

determining theoretical ultrasonic detection noise of the intermediate blank according to the ultrasonic detection noise required by the forge piece acceptance standard; calculating the forging-modifying fire number according to the difference value of theoretical ultrasonic detection noise of the intermediate billet and actual ultrasonic detection noise of the bar stock and the reduction value of the blank noise of each upsetting-drawing process, and formulating a forging-modifying process;

carrying out re-forging on the bar stock according to a re-forging process to obtain an intermediate blank;

die forging is carried out on the intermediate blank to obtain a forging blank;

and (3) roughly processing the forging blank to remove the surface covering and the oxide layer, and then carrying out heat treatment.

2. The method for preparing a thick large variable cross-section Ti-6242 alloy blisk forging according to claim 1,

increasing (6-9) dB of ultrasonic detection noise required by acceptance criteria to obtain theoretical ultrasonic detection noise of the intermediate blank;

and calculating the forging change number according to the principle that the noise of the blank ultrasonic detection is reduced by (3-6) dB every time the blank is upset and pulled.

3. The method for preparing the thick and large variable cross-section Ti-6242 alloy blisk forging piece according to claim 1, wherein during forging modification: heating temperature of the billet is T _βThe deformation amount of each upsetting is controlled to be 35-75 percent at the temperature of minus 20-45 ℃.

4. The method for preparing the thick and large variable cross-section Ti-6242 alloy blisk forging piece according to claim 3, wherein the hot blank is wrapped by heat insulation materials during forging.

5. The preparation method of the thick and large variable cross-section Ti-6242 alloy blisk forging piece according to claim 1, characterized in that the forging piece blank obtained by die forging has central blind holes (1) at two ends, the side wall of the central blind hole (1) is a conical surface, and the side wall of the central blind hole (1) is connected with the bottom of the hole through an arc surface, wherein the center of the bottom of one central blind hole (1) is recessed downwards to form a stepped positioning hole (2), the other central blind hole (1) is located in the hub (3) of the forging piece blank, and the surfaces of the outer wall of the forging piece blank are connected through the arc surface; the blade disc body (4) is designed into a double-inclined plane along with the formation, and a test ring (5) is reserved on the outer circumferential surface of the blade disc body (4).

6. The method for preparing the thick large variable cross-section Ti-6242 alloy blisk forging piece according to claim 1, characterized in that a die forging press is adopted for die forging: in the speed range of 3-15 mm/s, firstly pressing an intermediate value at a constant speed, and then uniformly pressing to a target value; heating temperature T _β- (30-40) DEG C, and the die forging deformation is 40-80%.

7. The method for preparing the thick and large variable cross-section Ti-6242 alloy blisk forging piece according to claim 5, wherein in rough machining, the step positioning hole (2) is machined into a through hole; processing the side wall of the central blind hole (1) and the outer circumferential surface of the hub (3) into straight surfaces; processing the rest of the inner and outer surfaces; and (5) reserving a test ring during processing, and reserving finish machining allowance on the inner surface and the outer surface of the forging blank.

Technical Field

The invention relates to the technical field of forging, in particular to a preparation method of a thick and large variable cross-section Ti-6242 alloy blisk forging.

Background

In the field of aeroengines, low oil consumption, large thrust-weight ratio and low noise are important indexes for measuring the quality of the engines. Along with the requirement of development of times, a turbofan engine with a large bypass ratio becomes one of the best choices of civil aviation engines, and in the field of engine manufacturing, the large bypass ratio means that the size of the engine is gradually increased, thick variable-section parts become necessary components, the requirement on a thick variable-section blisk forging with excellent performance is extremely urgent, and the breakthrough of the preparation technology is the premise and the basis for developing the turbofan engine with the large bypass ratio.

The thickness of the product is often in conflict with the hardenability of the material, the structural size easily exceeds the inherent hardenability limit of the material, the mechanical property of the forge piece is seriously influenced, the required forming load is multiplied, the requirement on the equipment capacity is higher, and the bearing load of the die is greatly increased. The cross-section is changeable, and the homogeneity of warping for the body brings great difficulty, and the design phase needs fully to carry out numerical simulation work, carries out configuration optimization in order to improve the body and warp the rationality. At present, the engineering research on the thick and large variable cross-section Ti-6242 alloy blisk forge piece is less, the products are in the test stage and cannot be popularized and applied to actual production, and a method for obtaining the thick and large variable cross-section Ti-6242 alloy blisk forge piece with stable quality and reliability is rarely reported.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of a thick and large variable cross-section Ti-6242 alloy blisk forging, aiming at the characteristics of Ti-6242 alloy materials, obtaining the thick and large variable cross-section Ti-6242 alloy blisk forging with excellent structure and performance, and being capable of being popularized and applied to actual production.

The technical scheme adopted by the invention for solving the technical problem is as follows: the preparation method of the thick and large variable cross-section Ti-6242 alloy blisk forging piece comprises the following steps

Carrying out ultrasonic detection on the bar material meeting the technical requirements to obtain the ultrasonic actual wave detection noise of the bar material;

determining theoretical ultrasonic detection noise of the intermediate blank according to the ultrasonic detection noise required by the forge piece acceptance standard; calculating the forging-modifying fire number according to the difference value of theoretical ultrasonic detection noise of the intermediate billet and actual ultrasonic detection noise of the bar stock and the reduction value of the blank noise of each upsetting-drawing process, and formulating a forging-modifying process;

carrying out re-forging on the bar stock according to a re-forging process to obtain an intermediate blank;

die forging is carried out on the intermediate blank to obtain a forging blank;

and (3) roughly processing the forging blank to remove the surface covering and the oxide layer, and then carrying out heat treatment.

Furthermore, the increase (6-9) dB of the ultrasonic detection noise required by the acceptance standard is the theoretical ultrasonic detection noise of the intermediate blank;

and calculating the forging change number according to the principle that the noise of the blank ultrasonic detection is reduced by (3-6) dB every time the blank is upset and pulled.

Further, the heating temperature of the blank is T when forging is changed _βThe deformation amount of each upsetting is controlled to be 35-75 percent at the temperature of minus 20-45 ℃.

Further, the hot blank is wrapped by a heat-insulating material during forging.

Furthermore, two ends of a forging blank obtained by die forging are provided with central blind holes, the side walls of the central blind holes are conical surfaces, the side walls of the central blind holes are connected with the hole bottoms through arc surfaces, the center of the hole bottom of one central blind hole is sunken downwards to form a stepped positioning hole, the other central blind hole is positioned in the hub of the forging blank, and all the surfaces of the outer wall of the forging blank are connected through the arc surfaces; the blade disc body is designed into a double-inclined plane along with the formation, and a test ring is reserved on the outer circumferential surface of the blade disc body.

Further, die forging is performed using a die forging press: in the speed range of 3-15 mm/s, firstly pressing an intermediate value at a constant speed, and then uniformly pressing to a target value; heating T _β- (30-40) DEG C, and the die forging deformation is 40-80%.

Further, during rough machining, the step positioning hole is machined into a through hole; processing the side wall of the central blind hole and the outer circumferential surface of the hub into straight surfaces; processing the rest of the inner and outer surfaces; and (4) retaining a test ring during processing, and reserving finish machining allowance on the inner surface and the outer surface of the forging blank.

Compared with the prior art, the invention has the beneficial effects that: through the establishment of the flaw detection index of the intermediate billet, the establishment of the forging process of the intermediate billet, the optimization design of the forge piece, the establishment of the die forging process, the control of the structure adjustment of the forge piece before heat treatment and specific process measures, the ultrasonic detection noise of the manufactured forge piece meets the acceptance criteria, the quality of the forge piece is ensured, and the method can obtain the blisk forge piece with stable and reliable quality.

Drawings

FIG. 1 is a schematic design view of a thick large variable cross-section alloy blisk forging;

FIG. 2 is a schematic illustration of a forging blank;

FIG. 3 is a schematic illustration of a forging blank after rough machining;

FIG. 4 is a schematic view of a water immersion ultrasonic inspection position;

reference numerals: 1-central blind hole; 2, positioning a stepped hole; 3, a hub; 4, a blade disc body; and 5, trial ring.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The preparation method of the thick and large variable cross-section Ti-6242 alloy blisk forging piece comprises the steps of ultrasonic detection material selection, forging change, die forging, rough machining, heat treatment and the like, and specifically comprises the following steps:

and carrying out ultrasonic detection on the bar stock meeting the technical requirements to obtain the actual ultrasonic detection noise of the bar stock. The ultrasonic flaw detection is a common detection mode in the prior art, and can detect the defects of inclusions, cracks, shrinkage cavities, white spots, layering and the like in the blank, so as to judge the quality of the product. The noise represents the uniformity of the tissue, the smaller the ultrasonic detection noise is, the higher the quality of the product is, and conversely, the higher the ultrasonic detection noise is, the worse the quality of the product is.

In order to ensure that the ultrasonic detection noise of the manufactured forge piece meets the acceptance standard, the theoretical ultrasonic detection noise of the intermediate blank is determined according to the ultrasonic detection noise required by the acceptance standard of the forge piece. The acceptance standard of the thick and large variable cross-section Ti-6242 alloy blisk forge piece is specified on ultrasonic detection noise, therefore, the ultrasonic detection noise required by the acceptance standard is known, the difference value of the theoretical ultrasonic detection noise of the intermediate blank and the ultrasonic detection noise required by the acceptance standard is determined by the reduction amount of the ultrasonic detection noise caused by die forging, the reduction amount of the ultrasonic detection noise caused by die forging is determined firstly, and then the ultrasonic detection noise required by the acceptance standard and the reduction amount of the ultrasonic detection noise caused by die forging are used as the theoretical ultrasonic detection noise of the intermediate blank.

And calculating the forging-modifying fire number according to the difference value of theoretical ultrasonic detection noise of the intermediate billet and actual ultrasonic detection noise of the bar stock and the reduction value of the blank noise of each upsetting-drawing process, and formulating the forging-modifying process. The improved forging can improve the uniformity of the blank structure and improve the structure performance, and the ultrasonic noise of the blank after the improved forging can be reduced. According to the difference value of theoretical ultrasonic detection noise of the intermediate billet and actual ultrasonic detection noise of the bar material and the influence of each hot forging on the ultrasonic detection noise, the hot forging changing number can be determined, and the fact that the actual ultrasonic detection noise of the intermediate billet is smaller than or equal to the theoretical ultrasonic detection noise of the intermediate billet after the hot forging changing is completed is guaranteed.

And (3) re-forging the bar stock according to the re-forging process to obtain an intermediate blank, and performing ultrasonic detection on the intermediate blank to ensure that the post-processing is performed after the theoretical ultrasonic detection noise of the intermediate blank is met. The purpose of the improved forging is to refine the structure and improve the uniformity of the structure, including the process of repeated upsetting and drawing and upsetting into an intermediate blank.

And performing die forging on the intermediate blank to obtain a forging blank.

And (3) roughly processing the forging blank to remove the surface covering and the oxide layer, and then carrying out heat treatment to obtain the forging.

And finally, carrying out ultrasonic detection on the forging piece, and judging whether the ultrasonic detection noise of the forging piece meets the acceptance requirement.

According to the invention, the theoretical ultrasonic detection noise required by the acceptance standard of the intermediate billet is pushed backwards according to the ultrasonic detection noise required by the acceptance standard of the forge piece and the influence of die forging on the ultrasonic detection noise, and the forging-modifying process is determined according to the difference value of the theoretical ultrasonic detection noise of the intermediate billet and the actual ultrasonic detection noise of the bar, so that the influence of forging-modifying and die forging on the ultrasonic detection noise of the forge piece can be controlled, and the quality of the forge piece can meet the acceptance standard. In addition, the invention can make different forging-modifying processes for bars with different ultrasonic detection noises, ensures that the forgings made of each bar can meet the acceptance requirements under the condition that the quality of raw materials is difficult to be completely unified, achieves the aim of stable and reliable production quality, and can be popularized and applied to actual production.

And improving the ultrasonic detection noise required by the acceptance standard by 6-9 dB, namely obtaining the theoretical ultrasonic detection noise of the intermediate blank. If the reduction degree of the ultrasonic detection noise of the prepared intermediate billet is larger than the range, the ultrasonic effect of the forging is not greatly improved, the heat number is increased, and the mechanical property of the part of the forging is damaged; if the range is smaller than the range, the ultrasonic detection noise of the forged piece can exceed the standard.

And calculating the forging change number according to the principle that the noise of the ultrasonic detection of the pierced billet is reduced by (3-6) dB every time the pierced billet is upset and pulled.

When forging, the heating temperature of the blank is T _βThe deformation amount of each upsetting is controlled to be 35-75 percent at the temperature of minus 20-45 ℃.

And during forging, the thermal insulation material is used for wrapping the hot blank.

The specific process of die forging comprises the following steps: performing die forging by using an 800MN large die forging press, pressing an intermediate value at a constant speed within the speed range of 3-15 mm/s, and then uniformly pressing to a target value; heating temperature T _β- (30-40)/DEG C, and the die forging deformation is 40-80%.

The process parameter ranges are all constraint conditions for preparing stable and reliable forgings, and are obtained through multiple tests according to the characteristics of Ti-6242 alloy materials. The selection range of the process parameters is defined, and the method is a technical point for popularization and application.

The thick and large variable-section alloy blisk forging piece disclosed by the invention comprises a hub 2 and a blisk body 4, wherein a central through hole is formed in the hub 2 and the blisk body 4. Because the appearance and the hole structure of forging are more complicated, it is difficult direct die forging shaping, in order to reduce the degree of difficulty of die forging, and reduce the influence to the forging internal quality in the die forging process, need optimize the structure of forging blank before the die forging, make the mould according to the structure and the size of forging blank, then forge.

Specifically, two ends of a forging blank obtained by die forging are provided with central blind holes 1, the side walls of the central blind holes 1 are conical surfaces, the side walls of the central blind holes 1 are connected with hole bottoms through arc surfaces, the center of the hole bottom of one central blind hole 1 is downwards sunken to form a stepped positioning hole 2, the other central blind hole 1 is positioned in a hub 3 of the forging blank, the outer circumferential surface of the hub 3 of the forging blank is also set as a conical surface, and all surfaces of the outer wall of the forging blank are connected through arc surfaces; a test ring 5 is reserved on the outer circumferential surface of the blade disc body 4. The center through hole of the forging is changed into two center blind holes 1 and a stepped positioning hole 2. The side wall of the central blind hole 1 and the outer circumferential surface of the hub 3 are changed into conical surfaces, all the surfaces of the outer wall of the forging blank are connected through arc surfaces, and the blade disc body 4 is designed into a double-inclined surface along with the formation so as to facilitate demoulding. And the test ring 5 is used for sampling detection after heat treatment and can represent the mechanical property of delivered forgings.

And (4) roughly machining the forging blank according to the design structure and size of the forging, and performing opposite rough machining on the inner surface and the outer surface of the forging blank to leave finish machining allowance. Set up finish machining allowance for being greater than or equal to 4mm, can satisfy the finish machining requirement after the thermal treatment, guarantee that the forging size after the finish machining accords with the design size. The specific rough machining content comprises the following steps: processing the stepped positioning hole 2 into a through hole, and processing the side wall of the central blind hole 1 and the outer circumferential surface of the hub 3 into straight surfaces; the remaining inner and outer surfaces of the forging blank are machined to produce a heat treated blank as shown in figure 3. The rough machining can remove surface covering and oxides, limit machining is conducted on the stepped positioning holes 2, the central blind holes 1 and the hubs 3 at the thick and large parts, most machining allowance is removed, only finishing allowance identical to that of other parts is left, the test ring 5 is not machined locally, the size of a forging blank is made to be close to the design size of a forging as far as possible, the overall structure tends to be balanced, and therefore all parts can meet the requirements of a heat treatment process. The above processes are not sequential.