The controller controls the gas supply of the gas supply unit so as to maintain a pressure in a metal pipe material at a first pressure when a gas is supplied into the metal pipe material which is formed into a pipe portion in a main cavity portion in a state where an upper die and a lower die are joined to each other. It is possible to prevent pressure drop in the pipe portion caused by cooling of the pipe portion due to a contact between the dies, and the pipe portion. Thus, it is possible to suppress a decrease in a force for pressing the pipe portion against the dies. It is possible to suppress a decrease in adhesion between the pipe portion and the dies when the metal pipe is formed, and it is possible to suppress occurrence of variations in hardenability in the pipe portion.

An accurate springback compensation method for sheet hydroforming component based on liquid volume control is related to a springback compensation method for curved surface part hydroformed with liquid as a punch during deep drawing process. According to the difference between a theoretical volume and a post-springback volume of a target part, an elastic deformation of the die is induced by liquid pressure, the die deformation amount is controlled to be equal to the springback amount. The accurate springback compensation control of a curved surface part is realized to overcome the problems of thickness or mechanical properties variations for different batches of sheets, and the manufacture error of the mould is considered to meet the design requirements. The liquid volume compensation is on-line and in-situ performed without mould re-machining. The advantages is good precision, simple process, high efficiency, short cycle and low cost.

An accurate springback compensation method for sheet hydroforming component based on liquid volume control is related to a springback compensation method for curved surface part hydroformed with liquid as a punch during deep drawing process. According to the difference between a theoretical volume and a post-springback volume of a target part, an elastic deformation of the die is induced by liquid pressure, the die deformation amount is controlled to be equal to the springback amount. The accurate springback compensation control of a curved surface part is realized to overcome the problems of thickness or mechanical properties variations for different batches of sheets, and the manufacture error of the mould is considered to meet the design requirements. The liquid volume compensation is on-line and in-situ performed without mould re-machining. The advantages is good precision, simple process, high efficiency, short cycle and low cost.

Disclosed is a method for forming a tube with high internal pressure and low external pressure. The method comprises: putting a tube to be formed into a cavity, such that a bulging area (15) is formed between the tube to be formed and an inner wall of the cavity; continuously injecting a low-pressure fluid into the bulging area, and then injecting a high-pressure fluid into the interior of the tube to be formed, the high-pressure fluid creating a pressure on an outer wall of the tube to be formed such that the tube to be formed starts to expand to the bulging area; stopping the supply of the low-pressure fluid when the tube is bulged to conform to the inner wall of the cavity; and taking the formed tube out to complete a working cycle. Further disclosed is a forming machine for forming a tube according to the above method. According to the machine for forming a tube with high internal pressure and low external pressure, a mold body (1) is provided with a first through hole (13) and a second through hole (14) for circulating a low-pressure fluid into and out of a bulging area, so as to create a certain pressure P1 on the tube and ensure uniform bulging of the entire tube, thereby achieving a better forming effect.

The present invention discloses a method for manufacturing a thin-walled metal component by three-dimensional (3D) printing and hot gas bulging. The present invention uses 3D printing to obtain a complex thin-walled preform, which reduces a deformation during subsequent hot gas bulging. The present invention avoids local bulging thinning and cracking, undercuts at the parting during die closing, and wrinkles due to the uneven distribution of cross-sectional materials, etc. The present invention obtains a high accuracy in the form and dimension through hot gas bulging. After a desired shape is obtained by hot gas bulging, a die is closed to keep the component under high temperature and high pressure for a period of time, so that a grain and a phase of the material are transformed to form a desired microstructure.

The present invention discloses a method for manufacturing a thin-walled metal component by three-dimensional (3D) printing and hot gas bulging. The present invention uses 3D printing to obtain a complex thin-walled preform, which reduces a deformation during subsequent hot gas bulging. The present invention avoids local bulging thinning and cracking, undercuts at the parting during die closing, and wrinkles due to the uneven distribution of cross-sectional materials, etc. The present invention obtains a high accuracy in the form and dimension through hot gas bulging. After a desired shape is obtained by hot gas bulging, a die is closed to keep the component under high temperature and high pressure for a period of time, so that a grain and a phase of the material are transformed to form a desired microstructure.

A method and device for manufacturing a large-sized thin-walled tubular part by gas-liquid internal high pressure forming (IHPF). A gas and a liquid are filled at a certain volume ratio into a thin-walled blank. The pressure of the gas-liquid mixed fluid is mainly determined by the gas pressure. During the deformation of the thin-walled blank, due to a large compression ratio of the gas, the gas-liquid pressure will not basically change with the change of the volume of a blank cavity. A support pressure on the cavity of the thin-walled blank is stable in the entire forming process. In addition, even if there is a slight leakage of the liquid or gas during the forming process, the medium pressure inside the blank will not fluctuate largely. In this way, embodiments lower the requirements for the sealing effect during the tubular part forming process.

A method and device for manufacturing a large-sized thin-walled tubular part by gas-liquid internal high pressure forming (IHPF). A gas and a liquid are filled at a certain volume ratio into a thin-walled blank. The pressure of the gas-liquid mixed fluid is mainly determined by the gas pressure. During the deformation of the thin-walled blank, due to a large compression ratio of the gas, the gas-liquid pressure will not basically change with the change of the volume of a blank cavity. A support pressure on the cavity of the thin-walled blank is stable in the entire forming process. In addition, even if there is a slight leakage of the liquid or gas during the forming process, the medium pressure inside the blank will not fluctuate largely. In this way, embodiments lower the requirements for the sealing effect during the tubular part forming process.

An expansion forming apparatus that shapes a metal material with a die includes an electrode that comes into contact with the metal material and performs energization heating, and an electrode mounting unit having an electrode movement actuator that moves the electrode along an extension direction of the metal material during heating.

An expansion forming apparatus that shapes a metal material with a die includes an electrode that comes into contact with the metal material and performs energization heating, and an electrode mounting unit having an electrode movement actuator that moves the electrode along an extension direction of the metal material during heating.