Abstract: The present invention discloses a rolling-bulging forming hydraulic machine for tubular products, which includes a frame. The frame is provided with an upper rolling mechanism, a lower rolling mechanism, a fixed liquid bulging hydraulic cylinder and a movable liquid bulging hydraulic cylinder. The upper rolling mechanism and the lower rolling mechanism are arranged oppositely, and the upper rolling mechanism and the lower rolling mechanism are used to roll surfaces of a to-be-machined tubular product. The fixed liquid bulging hydraulic cylinder and the movable liquid bulging hydraulic cylinder are arranged oppositely, and the fixed liquid bulging hydraulic cylinder and the movable liquid bulging hydraulic cylinder are used to perform hydraulic bulging on the to-be-machined tubular product.

Abstract: A device for strengthening a straight pipe, including a first positioning mold, a second positioning mold, a split mold, a rounding mold, a first cavity and a second cavity. A method for strengthening a straight pipe is further provided. The split mold is adjusted to position the pipe. The pipe is inserted into the first and second positioning molds. First and second sealing rings are arranged in an inner cavity of the pipe. Hydraulic oil is injected into the first cavity to expand the pipe to perform an expanding deformation. When the hydraulic oil is unloaded, the split mold moves towards an axis of the first positioning mold to perform a reducing deformation. After the expanding and reducing deformations, the pipe is transported into the rounding mold, and hydraulic oil is injected into the second cavity to expand the pipe to perform the rounding.

Abstract: A method of forming a cylinder by spinning. A cylindrical blank is placed at a geometric center of a lower mold cavity, where a bottom of the lower mold cavity is provided with a straight hole, and a blank block is provided at the straight hole. The lower mold cavity is fixed on a rotating worktable such that the blank is directly below an upper indenter. The indenter is driven by an extruder to move vertically downwards to extrude the cylindrical blank. Meanwhile, the lower mold cavity is driven by the worktable to uniform rotate. The intender is kept still, and the lower mold cavity is continuously driven to rotate. The lower mold cavity moves vertically upwards to process an outer surface of the blank by rotation of a petal-shape inner wall. The formed cylinder is separated from the lower mold cavity to obtain the desired cylinder.

Abstract: The present invention discloses a rolling-bulging forming hydraulic machine for tubular products, which includes a frame. The frame is provided with an upper rolling mechanism, a lower rolling mechanism, a fixed liquid bulging hydraulic cylinder and a movable liquid bulging hydraulic cylinder. The upper rolling mechanism and the lower rolling mechanism are arranged oppositely, and the upper rolling mechanism and the lower rolling mechanism are used to roll surfaces of a to-be-machined tubular product. The fixed liquid bulging hydraulic cylinder and the movable liquid bulging hydraulic cylinder are arranged oppositely, and the fixed liquid bulging hydraulic cylinder and the movable liquid bulging hydraulic cylinder are used to perform hydraulic bulging on the to-be-machined tubular product.

Abstract: A device for strengthening a straight pipe, including a first positioning mold, a second positioning mold, a split mold, a rounding mold, a first cavity and a second cavity. A method for strengthening a straight pipe is further provided. The split mold is adjusted to position the pipe. The pipe is inserted into the first and second positioning molds. First and second sealing rings are arranged in an inner cavity of the pipe. Hydraulic oil is injected into the first cavity to expand the pipe to perform an expanding deformation. When the hydraulic oil is unloaded, the split mold moves towards an axis of the first positioning mold to perform a reducing deformation. After the expanding and reducing deformations, the pipe is transported into the rounding mold, and hydraulic oil is injected into the second cavity to expand the pipe to perform the rounding.

Abstract: A method of forming a cylinder by spinning. A cylindrical blank is placed at a geometric center of a lower mold cavity, where a bottom of the lower mold cavity is provided with a straight hole, and a blank block is provided at the straight hole. The lower mold cavity is fixed on a rotating worktable such that the blank is directly below an upper indenter. The indenter is driven by an extruder to move vertically downwards to extrude the cylindrical blank. Meanwhile, the lower mold cavity is driven by the worktable to uniform rotate. The intender is kept still, and the lower mold cavity is continuously driven to rotate. The lower mold cavity moves vertically upwards to process an outer surface of the blank by rotation of a petal-shape inner wall. The formed cylinder is separated from the lower mold cavity to obtain the desired cylinder.