Extrusion molding die and method in semi-solid preparation method of aluminum-clad magnesium composite pipe

Abstract

The invention relates to an extrusion moulding mold and method in a semi-solid state preparation method of an aluminium-coating magnesium composite pipe. The inner layer of the composite pipe is made from AZ91S magnesium alloy, and the outer layer of the composite pipe is made from 7075 aluminium alloy. The extrusion moulding method comprises preparation of blank, secondary heating and semi-solid state extrusion moulding, and specifically comprises the following steps: placing prepared aluminium alloy semi-solid state blank and magnesium alloy semi-solid state blank with solid fraction being 70%-90% into an extrusion cavity of an extrusion barrel through a hot charging process, and performing extrusion moulding to obtain the aluminium-coating magnesium composite pipe with the wall thickness of 4-8mm and the length of 1,200-3,000mm, wherein the preheating temperature of the mold is 250-300 DEG C, and the extrusion speed is 60-150mm / s. According to the invention, the bonding interface of the aluminium-coating magnesium composite pipe completely reaches the metallurgical bonding, and compared with other moulding methods, the extrusion moulding method has the advantages of high efficiency, short flow, good pipe quality, simple structure, and simplicity in implementation; the prepared aluminium-coating magnesium composite pipe is small in density, and high in specific strength and specific stiffness, the outer layer is corrosion-resistant, the inner layer is good in shock absorption and shock resistance, and the prepared aluminium-coating magnesium composite pipe is particularly suitable for the fields of manufacturing of baggage holders of high speed trains, seats, portable bicycle frames, high-grade lamps and lanterns, and the like, and has very wide application prospect.

Description

technical field [0001] The invention relates to a mold and a method for preparing an aluminum-clad magnesium composite pipe, in particular to an extrusion molding mold and a method for semi-solid preparation of the aluminum-clad magnesium composite pipe. Background technique [0002] Double-layer composite pipe refers to the pipe whose inner and outer layers are made of dissimilar metals through certain processing methods. The inner and outer metals have different properties respectively to meet the requirements of different working environments. At present, composite pipes have broad application prospects in many fields such as vehicle manufacturing, transportation pipelines, and aerospace. With the rapid development of my country's national economy, high-tech and national defense industry, the demand for composite pipes is increasing, and the requirements for product quality are also getting higher and higher. Especially in recent years, my country's resources and environ...

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Problems solved by technology

Obviously, there are at least two disadvantages in this method: firstly, the production cycle of the process is long, one-time forming cannot be realized, and the energy consumption is high; secondly, the composite pipe produced by welding, the inner pipe and the outer pipe are combined Not tight, the gap and stress between the tubes are easy to cause product failure

[0004] The liquid metal continuous casting composite method can also be used to prepare double-layer composite pipes (see: Su Yajun, Liu Xinhua, Wu Yongfu, etc. Microstructure and properties of copper-clad aluminum composite materials directly composited by horizontal continuous casting. Special casting and non-ferrous alloys, 2011,31(9):785-789), which belongs to the liquid phase-liquid phase composite method. This forming method is conducive to improving the quality of composite pipes, but there are high equipment investment costs (need specific casting equipment), high production temperature (The processing temperature is above 100°C of the alloy liquidus), low production efficiency (the average casting speed is only 60-90mm / min), high energy consumption, and difficult to accurately control the production process (drawing is prone to cracking, overlapping, etc. ) and other defects, which limit the prospect of its application

[0005] In addition, the traditional rolling crimping method and cladding welding method are all solid-solid phase composite methods, which have the disadvantages of long production process, high cost, heavy environmental burden, and difficulty in preparing special-shaped or large-sized composite materials. It is difficult to achieve the metallurgical bonding effect of pipe materials and inner and outer layer pipes (see: Luo Ruixue. Research on Extrusion Forming Technology of Bimetal Composite Pipe. Thermal Processing Technology, 2010,39(13):87-89)

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