A workpiece processing method includes: a section roll forming step of subjecting a flat plate shaped workpiece to forming to impart a prescribed cross-sectional shape thereto; a solution heat treatment step of subjecting the workpiece, after the section roll forming step has been performed, to solution heat treatment; a contour roll forming step of subjecting the workpiece, after the solution heat treatment step has been performed, to forming to bend the workpiece into an arcuate shape; and a stretch forming step of subjecting the workpiece, after the contour roll forming step has been performed, to forming to impart a curved shape, following a curved surface of a die, to the workpiece by bringing the workpiece into contact with the curved surface and inputting a tension load to the workpiece.

Methods are disclosed for forming metal workpieces made from a heat-treatable metal that has been shaped and tempered according to specified protocols that facilitate formation of large contoured unitary metal structures having welds that are retained in the finished structure, and finished metal structures made according to such methods.

An object of the present invention is to provide a bending die that has a simple configuration and is capable of bending a rod-shaped body in a three-dimensional XYZ direction quickly and reliably, the bending die comprising a pair of forming dies clamped in a Z direction, wherein the forming dies have, respectively, rod-shaped body-forming recess portions, and rod-shaped body guide portions for guiding a rod-shaped body to the rod-shaped body-forming recess portions, the rod-shaped body-forming recess portions are each formed into a shape with a semicircular cross section that defines, between the forming dies when clamping the forming dies, a long, cylindrical cavity for forming the rod-shaped body bent in a three-dimensional XYZ direction, and the rod-shaped body guide portions are each formed into a V-shape that spreads outward from both sides of each of the rod-shaped body-forming recess portions having a semicircular cross section.

An object of the present invention is to provide a bending die that has a simple configuration and is capable of bending a rod-shaped body in a three-dimensional XYZ direction quickly and reliably, the bending die comprising a pair of forming dies clamped in a Z direction, wherein the forming dies have, respectively, rod-shaped body-forming recess portions, and rod-shaped body guide portions for guiding a rod-shaped body to the rod-shaped body-forming recess portions, the rod-shaped body-forming recess portions are each formed into a shape with a semicircular cross section that defines, between the forming dies when clamping the forming dies, a long, cylindrical cavity for forming the rod-shaped body bent in a three-dimensional XYZ direction, and the rod-shaped body guide portions are each formed into a V-shape that spreads outward from both sides of each of the rod-shaped body-forming recess portions having a semicircular cross section.

To suppress occurrence of stress corrosion cracking in a weld due to tensile residual stress generated in a web or a middle rib in case of bend forming of an aluminum alloy extrusion having the weld on the web or/and the middle rib. In bend forming of the aluminum alloy extrusion, a peak position of tensile residual stress generated in the middle rib exists in a region other than the vicinity of the weld. Since the peak position is away from the weld by a distance, tensile residual stress in the weld is reduced, making it possible to suppress occurrence of stress corrosion cracking.

A NC machine for stretch bending and monitoring method for clamping force of round clamp thereof is invented, which includes a round head clamp, a hydraulic system and a clamping force monitoring device. The round head clamp includes a housing, an internal module arranged in the housing and a positioning member for positioning the internal module in the housing. The hydraulic system includes a hydraulic rod and a hydraulic ram for pushing the hydraulic rod. The clamping force monitoring device includes a sensor and a data processing module. The present invention is suitable for the workpiece of different shapes and sizes. In this invention, the clamping force can be adjusted in real time when it needs to be changed, and this not only can avoid the problems of excessive energy consumption, excessive clamping marks and damage of the workpiece, but also save energy and protect the workpiece.

A NC machine for stretch bending and monitoring method for clamping force of round clamp thereof is invented, which includes a round head clamp, a hydraulic system and a clamping force monitoring device. The round head clamp includes a housing, an internal module arranged in the housing and a positioning member for positioning the internal module in the housing. The hydraulic system includes a hydraulic rod and a hydraulic ram for pushing the hydraulic rod. The clamping force monitoring device includes a sensor and a data processing module. The present invention is suitable for the workpiece of different shapes and sizes. In this invention, the clamping force can be adjusted in real time when it needs to be changed, and this not only can avoid the problems of excessive energy consumption, excessive clamping marks and damage of the workpiece, but also save energy and protect the workpiece.

A tensioning device for a sheet of material that includes a first ring with protrusions, a second ring, and a shaft. The first ring and the second ring are positioned such that the sheet of material can be clamped between the first ring and the second ring. The shaft has an outer surface, the outer surface includes a spiral race such that the protrusions of the first ring follow the spiral race, allowing the first ring and the second ring to displace linearly causing the sheet of material to be stretched. The spiral race includes a plurality of notches that correspond to the protrusions.

A tensioning device for a sheet of material that includes a first ring with protrusions, a second ring, and a shaft. The first ring and the second ring are positioned such that the sheet of material can be clamped between the first ring and the second ring. The shaft has an outer surface, the outer surface includes a spiral race such that the protrusions of the first ring follow the spiral race, allowing the first ring and the second ring to displace linearly causing the sheet of material to be stretched. The spiral race includes a plurality of notches that correspond to the protrusions.

Methods for making curved pieces from continuous metal elements are provided. Such methods include advancing a continuous metal element through a calendering station such that each length of the element assumes a pre-established curvature; stopping advancement of the element after a curved length thereof has passed through a wrap-bending station located downstream of the calendering station; wrap-bending the length of the element located at the station, while simultaneously conveying the curved portion to a stretch-bending station; stretch-bending the curved portion; resuming advancement of the element until the wrap-bent length is at a cutting station; and cutting the element in the wrap-bent length, thus producing the desired curved piece. Curved pieces produced by such methods are also provided.