Apparatus and method for forming large-scale thin-walled ring shell by hot-press bending with internal gas pressure

An apparatus for forming a large-scale thin-walled ring shell by hot- press bending with internal gas pressure, comprising:

• a sealed pipe assembly, a die with different controlled temperature zones, a first electrode, a second electrode, a power supply and a compressed gas source device, wherein
• the die with different controlled temperature zones comprises a first die and a second die;
• a convex part of the first die is arranged opposite to a concave part of the second die;
• the convex part of the first die is provided with a plurality of first cooling channels and a plurality of first heating devices, and both the first cooling channels and the first heating devices are used to adjust the temperature of the first die cooperatively;
• the concave part of the second die is provided with a plurality of second cooling channels and a plurality of second heating devices, and both the second cooling channels and the second heating devices are used to adjust the temperature of the second die cooperatively;
• the sealed pipe assembly comprises a pipe, a first head and a second head;
• the first head and the second head are welded at the two ends of the pipe respectively;
• the pipe of the sealed pipe assembly is arranged between the convex part of the first die and the concave part of the second die;
• the first electrode is arranged at one end of the pipe, and the second electrode is arranged at the other end of the pipe;
• the first electrode is connected with an anode of the power supply, and the second electrode is connected with a cathode of the power supply;
• the first electrode and the second electrode are powered to electrify the sealed pipe assembly to heat it, so as to heat the sealed pipe assembly to a preset forming temperature;
• and
• the compressed gas source device is connected with the first head or the second head, and the compressed gas source device is used to charge a compressed gas to the sealed pipe assembly;
• wherein the compressed gas source device specifically comprises:
• a compressed gas source and a gas pressure controller, wherein
• the gas pressure controller is respectively connected with the compressed gas source and the sealed pipe assembly, and the gas pressure controller is used to control the gas pressure in the sealed pipe assembly;
• the compressed gas is selected from the group consisting of air, nitrogen, helium and argon;
• and
• the gas pressure in the sealed pipe assembly is 0.1-10 MPa;
• the sealed pipe assembly is made of an aluminum alloy, a magnesium alloy or a titanium alloy;
• the aluminum alloy is selected from the group consisting of 2000 series, 5000 series, 6000 series, 7000 series and 8000 series aluminum alloy;
• the magnesium alloy is selected from the group consisting of AZ series, RE series and ZK series magnesium alloy;
• the titanium alloy is selected from the group consisting of α titanium alloy and α+β titanium alloy;
• and
• the pipe has an outer diameter of 300-700 mm, and the outer diameter of the pipe is equal to the diameters of the first head and the second head;
• the pipe has a length of 1000-2500 mm;
• the pipe has a wall thickness of 1-5 mm.