A kind of ultra-fine grain rolling method of large-size aluminum alloy bar

Abstract

The invention relates to an ultra-fine grain rolling method for large-sized aluminum alloy rods, relates to the field of machining, and particularly relates to the ultra-fine grain rolling method forthe large-sized aluminum alloy rods. The ultra-fine grain rolling method for the large-sized aluminum alloy rods comprises the following steps of designing rolling tools: designing rollers and guidingplates, arranging the rollers to be double-curved-surface truncated-cone-shaped rollers, and arranging one surfaces of the guiding plates to be curved surfaces, wherein a busbar of each roller is formed by connected two curves; constructing a deformation zone: oppositely placing the curved surfaces of the two guiding plates, and placing the two rollers between the guiding plates, wherein a zone enclosed by the two guiding plates and the rollers is the deformation zone; and constructing an equal-ellipticity deformation zone: remaining the ellipticity in the deformation zone unchanged. According to the ultra-fine grain rolling method for the large-sized aluminum alloy rods provided by the invention, through designing the double-curved-surface truncated-cone-shaped rollers and the curved-surface-shaped guiding plates, and constructing the equal-ellipticity deformation zone, severe plastic deformation can be produced on the premise of remarkably inhibiting a heart Mannesmann effect.

Description

technical field [0001] The invention relates to the field of mechanical processing, in particular to an ultrafine-grain rolling method for large-size aluminum alloy rods. Background technique [0002] Ultrafine crystal / nanocrystalline materials and their preparation technology are one of the research hotspots in the field of material science. Research in this direction embodies people's efforts to continuously improve the strength and toughness of polycrystalline materials through continuous refinement of grains. Among them, the research results of severe plastic deformation (Severe Plastic Deformation, referred to as SPD) technology are eye-catching. [0003] At present, the mainstream SPD process includes five methods: high pressure torsion (HPT), equal channel angular extrusion (ECAP), cumulative stack rolling (ARB), multidirectional forging (MF) and torsion extrusion (TE), among which: [0004] (1) High-pressure torsional deformation: While loading a pressure of severa...

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Problems solved by technology

[0015] (1) During the ECAP deformation process, the blank is in full contact with the mold, and the friction force is large, so the forming load is large, the finished product size is small, and the material utilization rate is low, the production efficiency is low, and it is difficult to realize the preparation of large-scale ultra-fine-grained materials required by industrialization

[0016] (2) The forming load of HPT is huge. The existing forming equipment generally does not have the loading capacity of over tens of GPa for industrialized large-scale products, and is only suitable for the forming of ultra-thin products such as films. Usually, the blank before deformation is Φ10-15×1- 10mm cylinder

[0017] (3) The ARB process is limited by the volume of the deformation zone and the uniformity of deformation, and the thickness of the deformation zone is only mm level

At the same time, since the prepared ultrafine grains are elongated grains in the shape of cakes, their mechanical properties are worse than those of three-dimensional equiaxed grains.

Therefore, limited by the loading capacity and uneven deformation, ARB can only prepare ultra-thin sheets

[0018] (4) Due to the serious deformation inhomogeneity of MF and TE, the grain size is uneven, the stability of the grain structure is poor, and the performance is reduced, and it is also impossible to prepare large-size forgings

However, the ultrafine-grained aluminum alloys obtained in these patents have small geometrical dimensions and cannot be extended to the aerospace field for the time being.

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