Preparation method of large-diameter aluminum alloy tube

Abstract

The invention relates to a preparation method of a large-diameter aluminum alloy tube, relating to a preparation method of an aluminum alloy tube and aiming to solve the problems in the prior art that the large-diameter aluminum alloy tube with the tube wall thickness less than 2mm and with an excellent performance cannot be prepared with low cost and high production efficiency. In the method, an aluminum alloy rolled plate is obtained at first through blanking with a plate shearing machine, a cylindrical tube blank is prepared with a plate rolling machine, a tube blank to be welded is obtained through clamping with a clamp, mixing friction welding is carried out for welding, a cylindrical welded tube is obtained through rounding, and the large-diameter aluminum alloy tube is obtained finally sequentially through spinning and thermal treatment. The invention has the advantages that: 1, a high-quality spinning blank can be obtained; 2, a large-diameter tube can be prepared; 3, the mechanical properties are good; 4, the number of spinning procedures is reduced, no annealing treatment is needed in the procedures, the production cycle is shortened, and the cost is decreased; and 5, the dimensional accuracy is high. The method is mainly applied in production of the large-diameter aluminum alloy tube.

Description

technical field [0001] The invention relates to a method for preparing an aluminum alloy pipe. Background technique [0002] Under the development trend of lightweight, high performance, and low cost in the aerospace field, the demand for large-diameter aluminum alloy pipe fittings is gradually increasing, such as aircraft air intakes. Such pipe fittings are complex in shape, and most of them are hollow parts with variable cross-section along the bending axis, which have high requirements on the plasticity of the pipe; and the diameter of the pipe is mostly greater than 500mm, while the wall thickness is only 2-3mm. [0003] There are three main traditional forming processes for aluminum alloy pipes: [0004] 1) Hot extrusion method, currently the largest 125MN extrusion machine in China (Liaoning Zhongwang Group), the largest can only produce aluminum alloy pipes with a diameter of <620mm and a wall thickness of >8mm, and the forming cycle is long and the cost is hig...

AI Technical Summary

Problems solved by technology

[0009] The present invention solves the problem in the prior art that a large-diameter aluminum alloy pipe with a pipe wall thickness less than 2 mm and superior performance cannot be prepared at low cost and high productivity, and provides a method for preparing a large-diameter aluminum alloy pipe

[0011] Advantages of the present invention: 1. The present invention uses clamps to clamp the butt joint of the pipe blank to be welded into an Ω-shaped pipe blank to be welded, changing "the welded pipe into a welding plate", and then uses friction stir welding to solve the problem of the stirring head and the pipe. The excessive thinning of the weld wall thickness and poor mechanical properties caused by incomplete contact and friction of the billet fully demonstrate the advantages of high weld strength and good plasticity of the friction stir welding solid state connection method, thus obtaining high-quality spinning billets 2. The present invention can prepare large-diameter aluminum alloy pipes, because the final pipe size depends on the size of the aluminum alloy rolled plate when rolling; 3. The pipes prepared by the spinning method in the present invention have excellent pipe structure and mechanical properties, and the pipes The microstructure of the weld seam and the base metal is similar, which avoids the problem of the reduction of mechanical properties caused by the uneven structure of the traditional welded pipe, and the pipe is composed of fine equiaxed grains, with an average grain size of less than 5 μm, which is the same as that of the traditional aluminum alloy extruded pipe. Compared with 100 μm ~ 200 μm, it shows better mechanical properties; 4. The present invention uses a rolling plate with 1.5 to 4 times the wall thickness of the pipe to obtain the spinning blank, which solves the difficulty in obtaining the traditional large diameter spinning blank and the short and thick spinning blank. Pressing the billet leads to many spinning passes, and problems such as cracks are prone to occur during the spinning process, because the number of spinning passes is greatly reduced, and there is no need for annealing between passes, which effectively shortens the production cycle and reduces costs; 5. The present invention obtains The dimensional accuracy of large-diameter aluminum alloy pipes is much higher than that of extruded pipes. The pipe diameter tolerance is about 0.2% of the workpiece diameter, and the wall thickness tolerance is about 4% of the workpiece wall thickness.

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