A kind of magnesium alloy sheet rolling edge crack prediction and control method

Abstract

The invention relates to a magnesium alloy sheet rolling edge crack pre-judgment and control method and belongs to the field of metal material machining. Firstly, according to magnesium alloy of a specific brand, the critical fracture strain of the magnesium alloy under hot rolling conditions, a Zener-Hollomon expression for reflecting material performance and a basic model between the critical fracture strain, and a deformation temperature and a strain rate are determined; and then a hot rolling edge crack pre-judgment model containing material deformation activation energy and a basic rolling process parameter is determined. Accordingly, an edge crack is pre-judged, process optimization is conducted, and edge crack control is achieved. The hot rolling edge crack pre-judgment model contains factors such as the deformation activation energy Q for reflecting the material performance, the roll diameter r of the major parameter of rolling equipment, the rolling speed v of the rolling process parameter, the pre-rolling thickness H of a rolled piece, the post-rolling thickness h of the rolled piece, and the press quantity delta h=H-h. Through the magnesium alloy sheet rolling edge crack pre-judgment and control method, the magnesium alloy rolling edge crack can be pre-judged effectively, guidance is provided for process optimization, and then the purposes of retarding or controlling the edge crack, increasing the finished product ratio, improving the material performance and reducing cost are realized.

Description

technical field [0001] The invention belongs to the field of metal material processing, and in particular relates to a method for predicting and controlling edge cracks in rolling of magnesium alloy plates. Background technique [0002] Magnesium alloy is currently the lightest metal structural material that can be used industrially, and its specific gravity is only 1 / 4 of that of steel; it has a low elastic modulus, a large shock resistance coefficient and superior impact resistance, and the shock absorption effect is obvious; heat conduction High rate and non-magnetic, so it has better heat dissipation performance and shielding function; Compared with aluminum alloy, magnesium alloy has higher specific strength and rigidity, so the application field is wider than aluminum alloy; the production process consumes less energy And easy to recycle, known as the future green metal structure material. [0003] Magnesium alloy sheets are widely used in aerospace, rail transit, aut...

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Problems solved by technology

However, its special close-packed hexagonal crystal structure, poor plasticity at room temperature, fast heat dissipation and other factors make its fracture toughness low, and edge cracks are prone to occur during the rolling forming process, which greatly reduces the yield of magnesium alloy sheets. rate, thus greatly increasing its production cost, has become one of the main technical bottlenecks hindering the rapid development of the magnesium alloy plate industry

At present, the magnesium alloy sheet is mainly produced by extrusion blanking plus multi-pass small reduction rolling process. The width of the sheet produced by this method is limited and the efficiency is low.

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