The structural characteristics of aluminum alloy pipeline are briefly described

The practical structure of die casting die for aluminum alloy pipe parts is discussed. The mould adopts the two-stage joint core-pulling mechanism of hook, tooth fan and rack, and realizes the inclined core-pulling of pipe casting by using the die opening force, and at the same time realizes the other two side core-pulling of pipe casting through the corresponding two sets of inclined pin and slide block mechanisms. The mould structure is compact, the work is reliable, the molding casting quality is good.

Because the inner plastic pipe is protected by the outer metal pipe, the cause of plastic corrosion and aging is eliminated, and the plastic pipe has a durable performance. The outer metal tube is much more difficult to protect. Three corrosion prevention measures are adopted on the outer surface of the steel lined plastic pipe: carbon steel layer and steel pipe forming cathode for protection and rust prevention.

Epoxy primer, forming a dense polymer protective film on the surface of carbon steel layer, so as to isolate it from air and water, slow down the oxidation corrosion of carbon steel, thus improving the service life of the pipe. The third layer: top coat, strengthen the protective function of the film, improve the aesthetic degree of the product. In the buried use, adopt appropriate anti-corrosion measures to improve the service life of the system.

When aircraft fuel system USES aluminum alloy pipe connector to transfer oil, it has to bear the varying oil pressure. In the hydraulic pulse test simulating the actual working condition, the pipe connector fails because the pipe near the assembly position has cracks through the inner and outer surface.

By scanning electron microscope observation, the crack originated from the fringe micro-defects on the outer surface of the catheter. Under the action of the hydraulic pulse, the crack continuously extended ductility along the pipe diameter to the inner surface of the catheter. When the crack area of the catheter could not withstand the peak pressure of the hydraulic pulse, the crack directly penetrated into the inner surface of the catheter. The measures to improve the resistance to hydraulic impulse fatigue of the pipe connecting parts are put forward.