Abstract: A plurality of press devices 2 are arranged in a plastic working system. The plastic working system includes: a loop correction sensor 13 for watching a slack of a coil material C intermittently delivered from a preceding first press device 2a; and a second slack watching means 19 for watching a slack of the coil material C generated at the time of sending the coil material C to a succeeding second press device 2b. According to the slack generated by intermittent feeding of the coil material C sent from the first press device 2a, intermittent feeding is converted to continuous feeding by the feeding means 15. At the same time, the continuous feeding speed is subjected to speed increasing/decreasing control. On the other hand, by the second slack watching means 19, a slack of the coil material C is watched at the time of feeding the coil material C to the second press device 2b and the preceding first press device 2a is subjected to speed increasing/decreasing control.

Abstract: A plurality of press devices 2 are arranged in a plastic working system. The plastic working system includes: a loop correction sensor 13 for watching a slack of a coil material C intermittently delivered from a preceding first press device 2a; and a second slack watching means 19 for watching a slack of the coil material C generated at the time of sending the coil material C to a succeeding second press device 2b. According to the slack generated by intermittent feeding of the coil material C sent from the first press device 2a, intermittent feeding is converted to continuous feeding by the feeding means 15. At the same time, the continuous feeding speed is subjected to speed increasing/decreasing control. On the other hand, by the second slack watching means 19, a slack of the coil material C is watched at the time of feeding the coil material C to the second press device 2b and the preceding first press device 2a is subjected to speed increasing/decreasing control.

Abstract: A die roll 3 comprises a core part 3a which is formed of an elastic material and faces a punch part 2a of a punch roll 2. The core part 3a presses a bottom portion 4b of a drawn portion 4a of a metal material 4 and is separate from a surrounding die part 3b and is provided with a space 3c at the whole outer periphery of the core part 3a. In accordance with the above configuration, swelling is suppressed at the bottom portion 4b of the drawn portion 4a and production of large wrinkles, which is a reason for folds, can be prevented by increase of pressing areas for preventing wrinkles at both sides of the drawn portion.

Abstract: A die roll 3 comprises a core part 3a which is formed of an elastic material and faces a punch part 2a of a punch roll 2. The core part 3a presses a bottom portion 4b of a drawn portion 4a of a metal material 4 and is separate from a surrounding die part 3b and is provided with a space 3c at the whole outer periphery of the core part 3a. In accordance with the above configuration, swelling is suppressed at the bottom portion 4b of the drawn portion 4a and production of large wrinkles, which is a reason for folds, can be prevented by increase of pressing areas for preventing wrinkles at both sides of the drawn portion.

Abstract: In a method for manufacturing a nozzle hole plate suitable for use in a fuel injection valve, a nozzle hole is formed at a predetermined angle of inclination by press-working with a punch in a thin-plate base material of a nozzle hole plate. When the nozzle hole is formed by press-working, a bluntness (shear drop) and a break face are formed at the corners of the base material at the fluid entrance and the fluid exit of the nozzle hole respectively, and as a result of the formation of this shear drop and break face the flow changes and the injection quantity increases. The injection quantity of the nozzle hole is measured for each nozzle hole plate, and its deviation from a target value is detected. Then, on the basis of the measured injection quantity value, the base material around the fluid entrance of the nozzle hole is notched by press-working using a punch. The material of the base material dimpled by the notching is pushed toward the fluid entrance of the nozzle hole and the shear drop diminishes.

Abstract: A non-oriented magnetic steel sheet having excellent bending workability and magnetic characteristics is obtained by continuous annealing. The non-oriented magnetic steel sheet is obtained by the method comprising cold rolling a hot-rolled steel sheet, continuously annealing the steel sheet, and then performing skin pass rolling; the steel has a composition comprising about 0.005 mass % or less of C, about 0.05 to 0.30 mass % of Si, about 0.10 to 0.50 mass % of Mn, about 0.15 to 0.50 mass % of Al, and about 0.0050 mass % or less of N.