阅读说明：本技术 一种铝合金航空锻筒残余应力的消除方法 (Method for eliminating residual stress of aluminum alloy aviation forging cylinder ) 是由 程仁策 宋韦韦 赵国群 宋增金 方清万 罗顺成 韩兆玉 于 2020-05-07 设计创作，主要内容包括：一种铝合金航空锻筒残余应力的消除方法,包括如下步骤：步骤一：对已经锻造成形的锻筒进行固溶处理和淬火热处理。淬火过程中,在锻筒内部安装周向支撑架,防止长锻筒发生较大变形。步骤二：根据淬火后锻件的直径、壁厚、材料性能,确定施加冷胀形的变形量,根据计算出的冷胀形的变形量设计出对应的冷胀形冲头和下砧板；步骤三：将冷胀形冲头放入锻筒内,以2mm/s的下压速度使冷胀形冲头下压,直至冷胀形冲头到达锻筒底端,将锻筒上下翻转,使用相同的下压速度使冷胀形冲头再次到达锻筒的底端。本发明能够获得很好的残余应力消减效果,锻件各部位变形均匀,表面质量较高。(A method for eliminating residual stress of an aluminum alloy aviation forging cylinder comprises the following steps: the method comprises the following steps: and carrying out solution treatment and quenching heat treatment on the forged cylinder. In the quenching process, a circumferential support frame is arranged in the forging cylinder to prevent the long forging cylinder from generating large deformation. Step two: determining the deformation of the cold bulging according to the diameter, the wall thickness and the material performance of the quenched forging, and designing a corresponding cold bulging punch and a lower cutting board according to the calculated deformation of the cold bulging; step three: and (3) placing the cold expansion punch into the forging cylinder, pressing down the cold expansion punch at a pressing-down speed of 2mm/s until the cold expansion punch reaches the bottom end of the forging cylinder, turning the forging cylinder up and down, and enabling the cold expansion punch to reach the bottom end of the forging cylinder again at the same pressing-down speed. The invention can obtain good residual stress reduction effect, and each part of the forge piece is deformed uniformly and has higher surface quality.)

1. A method for eliminating residual stress of an aluminum alloy aviation forging cylinder is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: and carrying out solution treatment and quenching heat treatment on the forged cylinder. In the quenching process, a circumferential support frame is arranged in the forging cylinder to prevent the long forging cylinder from generating large deformation;

step two: determining a theoretical value of deformation amount of cold bulging to be applied according to the diameter, the wall thickness and the material performance of the quenched forging piece, determining the sizes of a corresponding cold bulging punch and a lower chopping board according to the calculated theoretical value of deformation amount of cold bulging and the diameter of a quenched forging barrel, and manufacturing corresponding punch and lower chopping board dies;

step three: and (3) placing the cold expansion punch into the forging cylinder, pressing down the cold expansion punch at a pressing-down speed of 2mm/s until the cold expansion punch reaches the bottom end of the forging cylinder, turning the forging cylinder up and down, and enabling the cold expansion punch to reach the bottom end of the forging cylinder again at the same pressing-down speed.

2. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: the solution treatment in the first step is carried out by putting the fixed forging cylinder into an aluminum alloy vertical solution heat preservation furnace, and preserving heat in furnace gas at the temperature of 454-521 ℃ for a specified time.

3. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: the quenching heat treatment operation of the first step is to ensure that the whole forging cylinder is completely filled with the quenching medium within 15s after the furnace door of the solid solution holding furnace is opened.

4. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: the support frame shape for the center be thickness 150 mm's cylindric supporting seat, the welding has 6 spinal branch vaulting poles of symmetry transmission form around the supporting seat, every spinal branch vaulting pole top is furnished with the cushion that matches with the forging pot inner wall.

5. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: in the quenching process of the first step, the quenching medium of the forging cylinder is aqueous solution at the temperature of 40-80 ℃.

6. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: the deformation of the cold bulging is 1-8%, and the calculation formula of the deformation of the cold bulging in the step two isD1 is the inner diameter of the forged piece after the bulging treatment, and D0 is the initial inner diameter of the forged piece.

7. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: the cold expansion punch in the second step and the third step is in a spindle shape with a thick middle part and two narrow ends along the height direction, the inclination angles of the sidelines at the two ends of the cold expansion punch are 5-10 degrees, the connecting part at the two ends of the cold expansion punch is a boss with the thickness of 5-30mm, the lower edge of the boss is a fillet with the thickness of 8-12mm, the periphery of the lower end of the cold expansion punch is provided with outer gear teeth, the cold expansion punch can be matched with a circular groove arranged at the central part of a lower chopping board in an inserting manner, inner gear teeth are arranged in the circular groove of the lower chopping board, the cold expansion punch can be embedded into the circular groove at the central part of the lower chopping board through a positioning mark, and the outer gear teeth are meshed with the inner gear teeth, so that the bottom end of a cylindrical part can also be fully deformed.

8. The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder according to claim 1, wherein the method comprises the following steps: the operation of the third step must be completed within 4 hours after quenching.

Technical Field

The invention belongs to the field of eliminating residual stress of an aviation forging cylinder, and particularly relates to a method for eliminating residual stress of an aluminum alloy aviation forging cylinder.

Background

The aluminum alloy material has a series of advantages of low density, high specific strength, good corrosion resistance and the like, and is widely applied to aviation and aerospace aircrafts. However, during the hot forming and heat treatment of aluminum alloy aviation products, large residual stress is generated inside the forged piece due to uneven deformation or different cooling speeds of materials at different thicknesses during quenching. The existing residual stress can generate a plurality of adverse consequences, so that the forging is easy to deform, warp and distort in the subsequent machining process, the dimensional deformation of the machined structural part is ultra-poor, parts cannot be assembled on the designated airplane part, and the whole batch of forging is scrapped, especially for aviation important aluminum alloy structural forgings, if the internal residual stress is large, the fracture failure and stress corrosion fracture can be accelerated, the service life of the structural part is greatly reduced, and even serious consequences are caused. Therefore, how to effectively eliminate the residual stress in the aviation aluminum alloy forging piece has very important significance.

Common methods for eliminating residual stress of aluminum alloy die forgings include a die cold pressing method, a die drawing method, a deep cooling method, a shot blasting method, mechanical vibration, a pressure maintaining aging method and the like, but the methods are all suitable for flat die forgings and are difficult to be suitable for eliminating residual stress of large-size forging cylinders. How to eliminate the residual stress in the aluminum alloy aviation forging cylinder is not yet a corresponding technology for practical production. Therefore, how to effectively eliminate the residual stress of the cylindrical aviation forging is a technical problem to be solved urgently by the technical personnel in the field.

Disclosure of Invention

The invention provides a method for eliminating residual stress of an aluminum alloy aviation forging cylinder, which is used for overcoming the defects in the prior art.

The invention is realized by the following technical scheme:

a method for eliminating residual stress of an aluminum alloy aviation forging cylinder comprises the following steps:

the method comprises the following steps: and carrying out solution treatment and quenching heat treatment on the forged cylinder. In the quenching process, a circumferential support frame is arranged in the forging cylinder to prevent the long forging cylinder from generating large deformation;

step two: determining the deformation of the cold bulging according to the diameter, the wall thickness and the material performance of the quenched forging, and designing a corresponding cold bulging punch and a lower cutting board according to the calculated deformation of the cold bulging;

step three: and (3) placing the cold expansion punch into the forging cylinder, pressing down the cold expansion punch at a pressing-down speed of 2mm/s until the cold expansion punch reaches the bottom end of the forging cylinder, turning the forging cylinder up and down, and enabling the cold expansion punch to reach the bottom end of the forging cylinder again at the same pressing-down speed.

In the method for eliminating residual stress of the aluminum alloy aviation forging cylinder, the solution treatment in the first step is carried out by placing the fixed forging cylinder into an aluminum alloy vertical solution heat-preserving furnace, and preserving heat for a specified time at the furnace gas temperature of 454-521 ℃.

In the method for eliminating the residual stress of the aluminum alloy aviation forging pipe, the quenching heat treatment in the first step is carried out after the furnace door of the solution heat preserving furnace is opened, so that the whole forging pipe is completely filled with the quenching medium within 15 s.

According to the method for eliminating the residual stress of the aluminum alloy aviation forging cylinder, in the quenching process of the first step, the forging cylinder is prevented from being greatly deformed, a circumferential support frame is arranged in the forging cylinder before solid solution treatment, the support frame is in a cylindrical support seat with the center being 150mm thick, 6 support rods in symmetrical emission shapes are welded around the support seat, and the top end of each support rod is provided with a cushion block matched with the inner wall of the forging cylinder.

According to the method for eliminating the residual stress of the aluminum alloy aviation forging cylinder, the quenching medium of the forging cylinder in the quenching process in the first step is an aqueous solution at the temperature of 40-80 ℃.

According to the method for eliminating the residual stress of the aluminum alloy aviation forging cylinder, the deformation amount of the cold bulging is 1-8%, and the calculation formula of the deformation amount of the cold bulging in the second step isD₁Is the inner diameter of the forged piece after bulging treatment, D₀Is the initial inside diameter of the forging.

The method for eliminating the residual stress of the aluminum alloy aviation forging cylinder comprises the following steps of step two and step three, wherein the cold expansion punch is in a spindle shape with a thick middle part and two narrow ends along the height direction, the inclination angles of the sidelines at the two ends of the cold expansion punch are 5-10 degrees, the connecting part at the two ends of the cold expansion punch is a boss with the thickness of 5-30mm, the lower edge of the boss is a fillet with the thickness of 8-12mm, the outer gear teeth are arranged on the periphery of the lower end of the cold expansion punch, the gear teeth of the cold expansion punch can be in plug fit with the circular groove in the central part of the lower chopping block, the inner gear teeth are arranged in the circular groove, the cold expansion punch can be embedded into the circular groove in the central part of the lower chopping block through the positioning mark, and at the moment, the gear is meshed with the gear teeth, so that the bottom end of the cylinder can be fully deformed.

In the method for eliminating the residual stress of the aluminum alloy aviation forging cylinder, the operation of the third step is required to be completed within 4 hours after quenching.

The invention has the advantages that: the method for eliminating the residual stress of the aluminum alloy aviation forging cylinder can obtain a good residual stress reduction effect, and each part of a forging piece is uniform in deformation and high in surface quality. In addition, the method can be realized by using a traditional forging press without using a special expanding machine, and can solve the problem of residual stress relief of the forging cylinder with large height-diameter ratio, which cannot be realized by the expanding machine. And the method has simple process and easy operation, and is suitable for industrial popularization and application. The invention can improve the comprehensive mechanics and stress corrosion resistance of the workpiece and ensure the product quality while ensuring that the forging cylinder almost completely eliminates the residual stress.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of the cold-bulging process of the present invention;

FIG. 2 is a schematic structural view of a cold-expansion punch of the present invention;

FIG. 3 is a schematic view of the construction of the lower anvil of the present invention;

FIG. 4 is a schematic structural view of the circumferential support frame of the present invention.

Reference numerals: 1. a cold-bulging punch; 2. forging a cylinder; 3. a cutting board is arranged; 4. inner gear teeth; 5. outer gear teeth; 6. a supporting seat; 7. a support bar; 8. cushion blocks; 9. a circular groove.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.