A method for controlling uniformity of thick and large-section TC21 forgings

Abstract

The present invention discloses a method for controlling uniformity of a thick and large-section TC21 forging, comprising: (1) during two-phase forging, controlling the pressing amount, feed amount and deformation amount of each forging; when changing between different passes, the anvil indentation is staggered with the previous fire, the deformation amount between different fires and between different passes of the same fire is gradually reduced, and the deformation amount of each fire is controlled within 50% to 60%; (2) during single-phase forging, firstly heating the temperature of the fire forging to a temperature above the phase transition point temperature, the forging has deformation amounts in three directions during deformation, the overall deformation amount is controlled within 55% to 60%, and the forging is cooled to room temperature by air after forging is completed; (3) during two-phase trimming, the deformation amount of the fire forging is controlled to 40% to 50%, and the forging is cooled to room temperature by air after forging is completed; (4) rough machining before heat treatment, the effective cross-sectional thickness of the forging is ≤200 mm, and heat treatment is performed after completion. The TC21 thick and large-section forging produced by the present invention has a large overall strength surplus, good microstructure consistency between the edge and the core, and a good strength-toughness matching effect.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy forging, and in particular relates to a method for controlling uniformity of a thick and large-section TC21 forging. Background Art

[0002] The new generation of aircraft is gradually developing towards high speed, large size and integration, and its key load-bearing parts are increasingly inclined to choose high-strength and high-toughness titanium alloys with excellent comprehensive performance. TC21 alloy is used as a titanium alloy material for the key backbone structure of the new generation of aircraft because of its advantages such as high strength, high toughness, high damage tolerance, excellent fatigue resistance, and welding performance cavity.

[0003] The new generation of aircraft has a larger structure, which leads to an increasing thickness and weight of the cross-section of its forgings. At present, the cross-section thickness of some TC21 forgings has exceeded the existing standard requirements, and the difficulty of regulating the uniformity of its organizational properties has increased exponentially. The main reason is the forging and cooling speed; the thicker the cross-section thickness of the forging, the more difficult it is for the organizational properties of the forging to meet the standard requirements. Due to the insufficient strength redundancy of the forgings and poor organizational uniformity, the balanced matching of strength performance and plastic toughness can only be achieved through repeated heat treatment, resulting in a high risk of scrapping the forgings. Summary of the invention

[0004] The purpose of the present invention is to provide a method for controlling uniformity of thick and large-section TC21 forgings, which improves the small strength margin and poor uniformity of structural properties of thick and large-section TC21 forgings by controlling parameters such as pressing amount, feed amount, and deformation amount.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A method for controlling uniformity of a thick and large-section TC21 forging is implemented by a forging machine, an anvil is installed on the forging machine, and the bottom and side surfaces of the anvil are rounded R, and the width is B. The control method comprises the following steps:

[0007] (1) During two-phase forging, control the reduction, feed and deformation of each forging; the reduction should not exceed 1 / 2R and the feed should be 2 / 3B;

[0008] When changing between different passes, the anvil indentation is staggered with the previous pass, and the deformation between different passes and between different passes of the same pass is gradually reduced, and the deformation of each pass is controlled at 50%~60%;

[0009] (2) When forging in the single-phase region, first heat the temperature of the forging to above the phase transition point. During deformation, the forging has deformation in three directions, and the overall deformation is controlled at 55-60%. After forging, the forging is cooled to room temperature by air cooling;

[0010] (3) During the two-phase zone dressing, the deformation of the fire forging is controlled at 40%~50%, and the forging is cooled to room temperature by air cooling after forging;

[0011] (4) Rough machining before heat treatment: Rough machining is performed on the forging according to the shape of the part so that the effective section thickness of the forging is ≤200 mm, and then heat treatment is performed after completion.

[0012] The beneficial effects of the present invention are as follows: the produced TC21 thick and large-section forgings have a large overall strength surplus, good microstructure consistency of the edge and the core, and good strength-toughness matching effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the process of the present invention.

[0014] Figure 2 It is a structural diagram of the present invention during forging.

[0015] Figure 3 It is a trend diagram of the deformation amount according to the number of fires and passes of the present invention.

[0016] Figure 4 This is a performance test result diagram of the forging forged by the method of the present invention. DETAILED DESCRIPTION

[0017] like Figure 1 As shown, this embodiment provides a method for controlling uniformity of thick and large-section TC21 forgings. The main improvement of the method of this embodiment lies in the forging pressure control of the forging during forging. The heat treatment process is implemented using methods that are beneficial to the existing technology. The main equipment for forging is the forging machine, and the anvil is the one that acts on the forging and applies a certain force.

[0018] The method for controlling uniformity of thick and large-section TC21 forgings comprises the following steps:

[0019] (1) During two-phase forging, control the amount of reduction, feed rate, and deformation of each forging.

[0020] like Figure 2 As shown, the pressing amount each time does not exceed 1 / 2R, where R is the fillet of the anvil, which can effectively avoid the occurrence of surface defects on the forgings;

[0021] The feed rate is about 2 / 3B, where B is the width of the anvil, which can make the core of the forging change relatively more uniform;

[0022] When changing between different passes, the anvil indentation should be staggered with the previous pass to prevent the cumulative deformation at the same position from being too large. The deformation between different passes and between different passes of the same pass should follow the principle of gradually decreasing. Figure 2 As shown, the deformation of each fire is controlled at 50%~60%.

[0023] (2) When forging in the single-phase region, first heat the temperature of the forging to the phase transition point temperature. During deformation, ensure that the forging has deformation in three directions to prevent excessive accumulation of variables in a single direction from causing texture. The overall deformation is controlled at around 55-60%. After forging, use air cooling to quickly cool the forging.

[0024] (3) During the two-phase zone trimming, the deformation of the forging is controlled at 40%~50%, and the forging is quickly cooled by air cooling after forging.

[0025] (4) Rough machining before heat treatment: Rough machining is performed on the forging according to the shape of the part so that the effective cross-sectional thickness of the forging is ≤200 mm. Heat treatment is then performed after completion, which can effectively improve the strength and microstructure uniformity of the forging.

[0026] The performance level and uniformity of the forging products produced by the method described in this embodiment are significantly improved. Figure 4 shown.

[0027] The above description is only a preferred implementation manner of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling uniformity of thick and large cross-section TC21 forgings, the method being implemented by a forging machine, the forging machine being equipped with an anvil, the bottom and side surfaces of the anvil being rounded R, the width of which is B, characterized in that: The control method comprises the following steps: (1) During two-phase forging, control the reduction, feed and deformation of each forging; the reduction should not exceed 1 / 2R and the feed should be 2 / 3B; When changing between different passes, the anvil indentation is staggered with the previous pass, and the deformation between different passes and between different passes of the same pass is gradually reduced, and the deformation of each pass is controlled at 50%~60%; (2) When forging in the single-phase region, first heat the temperature of the forging to above the phase transition point. During deformation, the forging has deformation in three directions, and the overall deformation is controlled at 55-60%. After forging, the forging is cooled to room temperature by air cooling; (3) During the two-phase zone dressing, the deformation of the fire forging is controlled at 40%~50%, and the forging is cooled to room temperature by air cooling after forging; (4) Rough machining before heat treatment: Rough machining is performed on the forging according to the shape of the part so that the effective section thickness of the forging is ≤200 mm, and then heat treatment is performed after completion.

Images