The practical structure of die casting die for Dalian aluminum alloy pipeline parts is given, and the structural characteristics and working principle of the die are discussed. The die adopts a two-stage combined core pulling mechanism of pull hook, tooth fan and rack. The oblique core pulling of the pipe casting is realized by using the opening force. At the same time, the other two lateral core pulling of the pipe casting are realized by the corresponding two sets of oblique pin slider mechanisms.

Seamless steel pipes are commonly used for compressed air pipelines in Dalian. The pipeline system is provided with valves, pressure reducing devices, oil and water drains, compensators, gas distributors and meters, which are selected and processed according to the design drawings. Appearance inspection shall be conducted for pipes and fittings. The pipes of high-pressure pipelines shall be subject to nondestructive testing by magnetic flaw detection and other methods.

The extrudable size range of Dalian compressed air pipeline varies with different extrusion methods. The large outer diameter of the aluminum alloy tube extruded by the conventional piercing needle extrusion method is 600-650mm, the small inner diameter is 5-15mm, and the small wall thickness is 2-5mm. Due to the strength and rigidity of the piercing needle, the small inner diameter and wall thickness of extruded aluminum alloy pipe are greatly limited.

The stress of the support of Dalian compressed air pipeline shall be calculated by the corresponding software. Under the allowable stress conditions, the limit support shall be used as far as possible to allow axial displacement of the pipeline. In this way, when the straight pipe section is not long, the fixed support and compensator can be omitted, which simplifies the pipeline form, reduces the pipeline cost, and is also conducive to the on-site construction.