CN106391741A - Aluminum alloy paddle profile and manufacturing process thereof - Google Patents

Abstract

The invention discloses a manufacturing process of an aluminum alloy blade profile, which adopts hot extrusion molding: an aluminum alloy ingot at 490-510° C. is extruded through an extrusion barrel at 440-460° C. to a mold at 470-480° C. for molding. The present invention also provides an aluminum alloy paddle manufactured by the above method. The manufacturing process is convenient to operate, simple and stable, and the aluminum alloy blade profile prepared by the method has excellent mechanical properties, meets various indexes of rotorcraft blades, and can realize mass production of rotorcraft blades.

Description

A kind of aluminum alloy paddle profile and its manufacturing process

technical field

The invention relates to the field of aviation, in particular to an aluminum alloy blade profile and a manufacturing process thereof.

Background technique

With the continuous development of aluminum alloy extrusion technology at home and abroad, aluminum alloy hot extrusion profiles are widely used in various industries. In recent years, the domestic aluminum extrusion industry has continuously introduced advanced equipment and technology, especially the localization of aluminum profiles for rail transit, which has greatly improved the domestic aluminum extrusion technology. However, in terms of extrusion production technology of multi-cavity, thin-walled and complex-section industrial profiles, the domestic aluminum extrusion industry is still at the low-end level in the world. Therefore, if we want to be at the forefront of the world's aluminum extrusion technology, we must continue to explore and make breakthroughs in the extrusion molding process of high-precision aluminum profiles.

Rotorcraft blades have a slender rotating structure, and the blade tip speed is usually above 200m/s under high-speed working conditions, which bears large centrifugal force loads and complex loads such as alternating aerodynamic loads. Therefore, higher requirements are put forward for its structural design and material properties. In terms of structural design, the cross-section of the rotor blade is mostly an asymmetric closed load beam with a solid and heavy leading edge and a thin and light trailing edge. It is usually divided into C-shaped beam structure, D-shaped beam structure and multi-tube beam structure according to the beam structure. Among them, the multi-tube beam structure blade has high torsional stiffness, good damage safety characteristics and excellent anti-ballistic performance, and has received extensive attention in the industry. However, in the prior art, for the production of blades with multi-tube beam structure, it is necessary to combine multi-tube beams, skins, fillers, and trailing edge strips, and the manufacturing cost and cycle are long.

Contents of the invention

The purpose of the present invention is to provide a manufacturing process of aluminum alloy blade profiles, which can obtain aluminum alloy blade profiles with excellent mechanical strength through simple hot extrusion molding technology, which is easy to operate, simple and stable in process, and can realize aluminum alloy blade profiles. Mass production of blade profiles.

Another object of the present invention is to provide an aluminum alloy blade profile, which has excellent mechanical properties, can meet the current specifications for rotorcraft blades, and can be well applied to the production and manufacture of rotorcraft.

Embodiments of the present invention are achieved like this:

The invention discloses a manufacturing process of an aluminum alloy blade profile, which adopts hot extrusion molding: an aluminum alloy ingot at 490-510°C is extruded through an extrusion barrel at 440-460°C to form a mold at 470-480°C.

An aluminum alloy paddle manufactured according to the above manufacturing process.

The beneficial effects of the embodiments of the present invention are: application practice proves that the multi-tube beam structure blade is designed as an integrated aluminum profile structure, and through hot extrusion molding and surface oxidation treatment, it can fully meet the working conditions of the rotorcraft blade. However, the structure of the blade profile is complex, which is a multi-cavity and thin-walled complex section. The alloy state requirement is 6005A-T6, and the curved surface is streamlined. Die processing and extrusion production are difficult. There are no domestic reports showing that it can be successfully extruded. The invention provides an aluminum alloy paddle and its manufacturing process, which preheats the extrusion cylinder, aluminum alloy ingot and mold, so that the aluminum alloy ingot maintains good plasticity during the entire hot extrusion forming process, successfully The aluminum alloy blade profile conforming to the rotorcraft blade standard was prepared by the hot extrusion molding process. The whole method is convenient to operate, and the process is simple and stable. The aluminum alloy blade profile prepared by the method has excellent mechanical properties, meets various indexes of rotorcraft blades, and can realize mass production of rotorcraft blades.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is a flow chart of the manufacturing process of an aluminum alloy blade profile provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the strong wind distribution of the online quenching of an aluminum alloy blade profile provided by the embodiment of the present invention;

Fig. 3 is a schematic cross-sectional view of an aluminum alloy blade profile provided by an embodiment of the present invention;

Fig. 4 is a schematic view of the appearance of an aluminum alloy blade profile provided by an embodiment of the present invention.

detailed description

In order to make the purpose, 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. Those who do not indicate specific conditions in the examples carry out according to conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

An aluminum alloy paddle according to an embodiment of the present invention and its manufacturing process will be described in detail below.

The invention proposes a manufacturing process of an aluminum alloy blade profile, which adopts hot extrusion molding: an aluminum alloy ingot at 490-510° C. is extruded through an extrusion cylinder at 440-460° C. to a mold at 470-480° C. for molding.

Further, in other preferred embodiments of the present invention, the alloy state of the selected aluminum alloy ingot is 6005A-T6. 6005A aluminum alloy is a medium-strength alloy with good extrudability, weldability, and corrosion resistance It is often used in the transportation industry, such as thin-walled and hollow large-scale aluminum alloy siding profiles required by high-speed trains, subway trains, double-decker trains and passenger cars.

Further, in other preferred embodiments of the present invention, an appropriate extrusion machine is selected according to the cross-sectional size, area and alloy state of the required aluminum alloy blade profile. Specifically, the criterion for judging whether it is suitable or not is that the extrusion ratio of the extruded profile is controlled at 30-60. The extrusion ratio determines the degree of deformation of the aluminum alloy ingot extrusion process. Reasonable selection of the extrusion ratio can not only improve the extrusion production efficiency, but also ensure that the profile has smaller grains, thereby improving the strength of the profile. For 6005A alloy, the reasonable range of extrusion ratio is 30-60.

Furthermore, in other preferred embodiments of the present invention, the advancing speed of the extrusion rod is 0.5-1 mm/s, and the outlet temperature is 520-550°C. Appropriate extrusion speed can avoid excessive temperature of ingot during extrusion and ensure uniform and stable internal structure of extruded profile.

Furthermore, in other preferred embodiments of the present invention, a natural gas heating furnace is used to heat the aluminum alloy ingot to 490-510°C. The use of natural gas long rod heating furnace can ensure the surface cleanliness of the aluminum alloy ingot, and can select the appropriate length of the aluminum alloy ingot for extrusion through thermal shearing. Specifically, the aluminum alloy ingot used for extrusion of the 6005A alloy has a length of 300-1000 mm.

Further, in other preferred embodiments of the present invention, put the qualified molds in the mold trial into a drawer-type mold heating furnace to heat to 470-480°C, the holding time is 4-6 hours, and the mold heating time cannot exceed 8 hours, otherwise Oxidation of the working belt will reduce the surface quality of the profile.

Furthermore, in other preferred embodiments of the present invention, the above manufacturing process further includes straightening and stretching the extruded profile, and cooling the extruded profile to below 60°C before straightening and stretching the extruded profile. The purpose of cooling to a sufficiently low temperature is to reduce or avoid the changes in external dimensions and wall thickness due to cooling shrinkage after straightening and stretching.

Furthermore, in other preferred embodiments of the present invention, the extruded profile is cooled by an online air-cooling quenching device, so that the surface temperature of the profile is reduced to 80-150°C, and then naturally cooled to below 60°C. Preferably, adjust the intensity and distribution of the online cooling wind, and start the online strong wind cooling and quenching treatment at a distance of 1m from the exit of the front beam of the extruder. The length of the cooling zone is 6m, and the surface temperature of the profile in the cooling zone is guaranteed to be below 150°C. Due to the irregular shape of the blade profile, the wall thickness of the tip side is thicker than that of the tail side. It is necessary to add a compressed air duct on the tip side to increase the cooling rate of the thick-walled tip and avoid side bending caused by uneven cooling on both sides. .

Furthermore, in other preferred embodiments of the present invention, the stretching ratio in the straightening and stretching process is 1-1.5%. Straightening and stretching needs to be carried out according to the material, cross-sectional shape and dimensional tolerance, and bending conditions. The selection of the optimal stretching rate is determined by checking the change in the tolerance of the cross-section of the profile before and after stretching. The determined optimal stretching rate must be guaranteed The stretched profile meets the dimensional tolerance requirements.

Further, in other preferred embodiments of the present invention, the finishing step further includes sawing the straightened and stretched extruded profile into a specified length. Preferably, for the sawn profiles, it is necessary to check the cutting slope, length, and curvature to be qualified, and then load them into baskets and trim the end faces to be flat. When the profiles are loaded into baskets, there needs to be room Reasonable gaps ensure the hot air circulation effect during the aging process.

Furthermore, in other preferred embodiments of the present invention, after straightening and stretching, artificial aging is carried out on the profile: the profile is heated to 170-180°C and kept for 8 hours, and then naturally cooled to room temperature.

The present invention also proposes an aluminum alloy blade profile prepared according to the above method.

Example

This embodiment proposes an aluminum alloy blade profile, which is obtained through the following steps using the process flow shown in Figure 1:

S1. The width direction of the aluminum alloy blade profile to be manufactured is 198.39mm, the height direction is 24mm, and the cross-sectional area is 924.4mm ² . In order to control the extrusion ratio at 30-60, select an extrusion machine with a corresponding diameter extrusion cylinder Extrusion is carried out, and its extrusion ratio obtained by calculation is 46.84, which meets the extrusion requirements. The extrusion machine is equipped with an online air-cooled quenching device, which can meet the production requirements of 6005A-T6 state. Therefore, the forward extrusion machine equipped with an online strong wind cooling and quenching device is selected to produce the aluminum alloy blade profile.

S2. Raise the temperature of the extrusion barrel to 440-460°C. When the embodiment is carried out, the extrusion machine is in normal operation, and the temperature of the extrusion cylinder is 447-453°C.

S3. The length of the first two extruded aluminum alloy ingots is 500mm, and the length of the subsequent extruded aluminum alloy ingots is within the range of 600-650mm. The temperature of the aluminum alloy ingots is heated to 490-510°C by a natural gas heating furnace. EXAMPLES In the actual production process, the temperature of the aluminum alloy ingot is 492°C-504°C.

S4. Heat the mold to 470-480° C. in a single-cavity drawer-type mold heating furnace. Specifically, in this embodiment, the mold is heated to 475° C., kept warm for 4 hours, and then released from the furnace, and assembled on the extruder.

S5. During the extrusion molding process using an extruder, the extrusion speed of the extruder is set to 0.8mm/s, and the outlet temperature of the profile is controlled to be 520-550°C. Specifically, in this embodiment, when the second aluminum alloy ingot is extruded, the profile outlet temperature reaches 527°C.

S6. The extruded profile is cooled by an online air-cooling quenching device, the surface temperature of the profile is reduced to below 150°C, and then naturally cooled to below 60°C. Figure 2 shows a schematic diagram of strong wind cooling on the extrusion line. By adjusting the air volume on the upper, lower and both sides of the profile, and adding compressed air ducts, the degree of side bending is effectively reduced. In this embodiment, when leaving the cooling zone, the surface temperature of the profile is about 115°C.

S7. After the profile is cooled to below 60°C, the optimum stretching rate is determined to be 1.1% by inspecting the tolerance change of the cross-section of the first aluminum alloy ingot extrusion profile before and after stretching, and the extrusion rate is determined based on this stretching rate. Profiles are straightened and stretched. It is worth noting that in other preferred embodiments of the present invention, the elongation rate calculated according to the material, cross-sectional shape, dimensional tolerance, and bending condition meets the processing requirements in the range of 1-1.5%, and subsequent processing can be performed.

S8. Sawing the rough products that have been straightened and stretched and the surface quality is qualified according to the fixed size requirements, after checking the cutting slope, length, and bending degree, they are loaded into baskets and the end faces are trimmed to be flat, and samples for mechanical performance testing at room temperature are cut. Put it into the basket and transfer to the aging process together.

S9, heat preservation at 175° C. for 8 hours for artificial aging to obtain a final aluminum alloy blade profile.

Through the implementation of the above process, the aluminum alloy blade profile was successfully extruded, and the schematic diagrams of the aluminum alloy blade profile are shown in Figure 3 and Figure 4 . According to the tensile test results of the room temperature mechanical properties of the sample, the average tensile strength and yield strength are 291.5MPa and 270.5MPa respectively. It is worth noting that in other preferred embodiments of the present invention, according to specific process conditions, the mechanical properties of the aluminum alloy profiles may vary slightly, but all of them can meet the tensile strength of 270MPa and the yield strength of 240MPa. Therefore, the hot extrusion process of aluminum alloy blade profiles for rotorcraft proposed by the present invention can effectively guide aluminum extrusion processing units to produce qualified blade profiles.

In summary, the present invention provides an aluminum alloy paddle and its manufacturing process, which preheats the extrusion cylinder, aluminum alloy ingot and mold, so that the aluminum alloy ingot can be maintained in good condition during the entire hot extrusion forming process. The plasticity of the aluminum alloy blade profile that meets the rotorcraft blade standard has been successfully prepared by the hot extrusion molding process. The whole method is convenient to operate, and the process is simple and stable. The aluminum alloy blade profile prepared by the method has excellent mechanical properties, meets various indexes of rotorcraft blades, and can realize mass production of rotorcraft blades.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a kind of processing technology of aluminium alloy blade section bar is it is characterised in that adopt hot extrusion molding：By 490～510 DEG C of aluminum Alloy cast ingot extrudes through 440～460 DEG C of recipient to 470～480 DEG C of mould molding.

2. a kind of processing technology of aluminium alloy blade section bar according to claim 1 is it is characterised in that described recipient Extruded velocity is 0.5～1mm/s, and outlet temperature is 520～550 DEG C.

3. a kind of processing technology of aluminium alloy blade section bar according to claim 1 is it is characterised in that described aluminium alloy is cast During ingot hot extrusion molding, extrusion ratio is 30～60.

4. a kind of processing technology of aluminium alloy blade section bar according to claim 1 is it is characterised in that described processing technology The extrusion profile also including hot extrusion molding is obtained carries out straightening pull, and before straightening pull, extrusion profile is cooled to 60 Below DEG C.

5. a kind of processing technology of aluminium alloy blade section bar according to claim 4 is it is characterised in that described extrusion profile After online air-cooled quenching device cools down, surface temperature, at 80～150 DEG C, then naturally cools to less than 60 DEG C.

6. a kind of processing technology of aluminium alloy blade section bar according to claim 4 is it is characterised in that described aligning draws Stretch, its extensibility is 1～1.5%.

7. a kind of processing technology of aluminium alloy blade section bar according to claim 6 is it is characterised in that rectify extrusion profile After vertical pulling is stretched, then section bar is sawed into specific length.

8. a kind of processing technology of aluminium alloy blade section bar according to claim 7 is it is characterised in that described section bar is through fixed After chi sawing, artificial aging must be carried out.

9. a kind of processing technology of aluminium alloy blade section bar according to claim 8 is it is characterised in that described artificial aging It is aluminium section bar to be warming up to 170～180 DEG C and is incubated 8h, then naturally cool to room temperature.

10. the aluminum that a kind of a kind of processing technology of the aluminium alloy blade section bar described in any one according to claim 1～9 is obtained closes Golden blade.