Alloy pipe material thermal extrusion method and extrusion mould

[0015] The structure and extrusion method of the alloy pipe hot extrusion die of the present invention are further described below with reference to examples.

[0016] like figure 1 As shown, a hot extrusion method and extrusion die for an alloy pipe include extrusion shaft 1, extrusion cylinder 2, extrusion pad 3, graphite pad 4, extrusion rod 5, extrusion blank 6, glass pad 7, The concave die 8 , the bottom plate 9 , the pressing plate 10 , the extrusion cylinder seat 11 , and the fixing seat 12 . The extrusion cylinder 2 is arranged in the extrusion cylinder seat 11, and is fixed on the bottom plate 9 with screws through the pressing plate 10. The concave die 8 is arranged at the lower end of the extrusion cylinder 2 and fixed in the groove on the bottom plate 9. 9 It is fixed on the base of the extruder by bolts, and then the heated glass pad 7 is placed on the top of the die 8, and then the heated extrusion blank 6 is placed, and then the graphite pad 4 and the extrusion pad 3 are placed. The pressing rod 5 is installed in the holes of the glass pad 7, the extrusion blank 6, the graphite pad 4, and the pressing pad 3, and is fixed on the extrusion shaft 1. under the head. During extrusion, the extrusion head of the extruder moves downward, and the blank 6 is extruded in the extrusion cylinder 2 through the extrusion shaft 1, the extrusion pad 3, and the graphite pad 4 to complete the extrusion forming process.

[0017] Because the working surface of the concave die is conical, and the sizing port is excessively circular, the arc is R3.5~R5, the working surface of the concave die and the glass pad is conical, and the cone angle is 35°≤θ≥45 °. Therefore, it is easy to attach a layer of glass film on the surface of the extruded billet, so that the heat preservation effect is good, the fluidity of the extruded billet is reasonable, and the extrusion force is low, which significantly improves the surface quality of the pipe and enables the extrusion billet to successfully complete the extrusion forming process.

[0018] A method for hot extrusion of a nickel-based alloy pipe material is to extrude the billet size: outer diameter D=85mm, inner diameter D=22mm, height L=200mm, and the extrusion process steps are:

[0019] (1) Preheating the mold: the mold preheating temperature is 450 ℃

[0020] (2) Coating lubricant: heating the extrusion blank and the extrusion cylinder to 150°C, coating the surface of the heated blank with a glass powder lubricant; coating the inner surface of the heating extrusion cylinder with a glass powder lubricant;

[0021] (3) Heating the extruded billet: place the extruded billet flat in a bell furnace, and feed N with an oxygen content of less than 0.2% and a dew point of -60°C. 2 Protective gas, heat up to 750°C after sealing, and then heat to 1150°C at a heating rate of <30°C/h;

[0022] (4) Extrusion: first install the heated glass pad on the top of the die, and then install the extrusion billet, graphite pad and extrusion pad in the extrusion cylinder in turn, and then start extrusion, and the extrusion speed is 85mm /s, the extrusion ratio is 9.5, and the billet extrusion temperature is 1120 °C;

[0023] (5) Annealing: put the hot extruded tube blank into cold water and cool it to room temperature to eliminate the thin layer with uneven grain distribution on the inner surface;

[0024] (6) Clean up the extruded tube blank: Clean the inner hole and outer surface of the extruded tube blank, which is beneficial to improve the surface quality during cold rolling in the subsequent process.

[0025] The present invention significantly improves the material fluidity and the forming effect during the hot extrusion forming of the pipe due to adopting a reasonable hot extrusion process and improving the transfer structure of the concave mold and the glass mat combined hot extrusion die.