Equal-passage variable-cross-section extruding mold and extrusion forming method for pipes

Abstract

The invention relates to an equal-passage variable-cross-section extruding mold and an extrusion forming method for pipes. The equal-passage variable-cross-section extruding forming is adopted, so the extruding forming of the pipes is formed through the twisting shearing deformation and the upsetting deformation on the cross section, and the combination of various deformation modes in one extruding process is realized. The pipe walls are in a strong three-direction press stress state through being limited by die cavities and polyurethane foam filling agents, in the deformation stage of circle-ellipse-circle and ellipse twisting change, materials enter twisting shearing deformation zones of the metal transition regions, the material internal tissues generate rotation and shearing stress under the effect of the shearing stress, the orientation of the material tissue structure is caused, i.e. a new tissue structure is formed, and the material tissue structure under the same deformation degree is improved. The mold and the method have the advantages that deformation degree higher than that of the traditional forming process can be obtained, the strain distribution and the stress distribution inside the pipes are improved, residue casting tissues of the pipes can be favorably crushed, the forms and the distribution of inclusions are changed, and the internal tissue defects of the pipes are eliminated.

Description

technical field [0001] The invention relates to the field of forming metal pipes such as aluminum, copper, steel, etc., in particular to an equal-channel variable-section extrusion die and an extrusion forming method. Background technique [0002] The use of pipe fittings and sleeves is all involved in the fields of aviation, aerospace, automobiles and mechanical equipment. Taking an aircraft as an example, the pipeline system is the lifeline of the aircraft, and its performance directly affects the overall performance of the aircraft. If the engine is compared to the heart of the aircraft, then the pipeline is like the blood vessels of the aircraft. Therefore, it is very important to improve the technical level of the pipeline system to improve the performance of the aircraft. [0003] At present, most metal pipes used in pipeline systems on the market adopt traditional forming methods, and most of them are seamless pipes (Baogang Science and Technology, 2002, 2: 21). The...

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Problems solved by technology

A variable-channel extrusion die proposed by Northwestern Polytechnical University in a patent application with a publication number of CN201371172, and a tire mold for long-axis forging blanks proposed in a patent application with a publication number of CN201711480U, and the publication number A device for preparing variable-channel ultra-fine-grained copper-aluminum wires proposed in the patent application of CN201862645U is formed by a variable-section torsional mold cavity that changes from a circular cross-section to an elliptical cross-section, and then from an elliptical cross-section to a circular cross-section. The prefabricated workpiece has the characteristics of simple structure, small load, low cost and high efficiency. It can be widely used in the production of bars and wires of steel and non-ferrous metals, as well as the production of large shaft parts, high-speed steel and powder metallurgy and other hard-to-deform materials. billet, but no one has used this simple subsequent processing method for pipes

[0006] The above-mentioned traditional pipe-making process is difficult to meet the needs of the growing aviation industry. Due to insufficient strength and the influence of deformation texture, cracking will occur during use, which will affect the safety and reliability of aircraft pipelines in severe cases.

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