The top plate section of the metal stock is pressed and clamped against a punch by a pad, a portion that will be at the outside of the L shaped curve is pressed and camped against a die by a blank holder, a bender is moved, and a vertical wall portion at the inside of the L shaped curved of the metal stock sheet and the flange portion joined to the vertical wall at the inside of the L shaped curve are molded. The metal stock sheet is moved in the direction toward the blank holder while the metal stock sheet being pressed and clamped, and a vertical wall portion at the outside of the L shaped curve of the L shaped hat shaped cross-section and the flange portion joined to the vertical wall at the outside of the L shaped curve are molded.

A press forming method for producing a saddle type final product comprises a first process of producing an intermediate product having a processing adjustment section, by cold press working against an ultrahigh tensile strength steel plate, to deform the side wall portions and flange portions at the both sides in the predetermined area, with the cross section of the top plate portion being maintained in a predetermined shape, and a second process of pressing at least the processing adjustment section, by cold press working against the intermediate product, with the cross section of the top plate portion being maintained in the predetermined shape. In at least one of the first process and second process, a processing target of the at least one process is bent in the direction opposite to the opening of the hat-shaped cross section, to produce the saddle type final product

A press forming method for producing a saddle type final product comprises a first process of producing an intermediate product having a processing adjustment section, by cold press working against an ultrahigh tensile strength steel plate, to deform the side wall portions and flange portions at the both sides in the predetermined area, with the cross section of the top plate portion being maintained in a predetermined shape, and a second process of pressing at least the processing adjustment section, by cold press working against the intermediate product, with the cross section of the top plate portion being maintained in the predetermined shape. In at least one of the first process and second process, a processing target of the at least one process is bent in the direction opposite to the opening of the hat-shaped cross section, to produce the saddle type final product

Provided are a press forming method capable of improving material yield while avoiding the risk of dimensional error increase at product forming sections in blank material when carrying out press forming, and a plate material expansion device used in this method. An end side of plate material for press forming is restricted by blank holding rollers, and pressure is applied to a middle location in the part that is restricted by a pressure roller. In this state, the plate material is transported in a rotating direction of the rollers being driven to continuously bend and extend the section receiving pressure. This bent and extended section is flattened with a flattening roller to obtain blank material wherein an end part is expanded.

Provided are a press forming method capable of improving material yield while avoiding the risk of dimensional error increase at product forming sections in blank material when carrying out press forming, and a plate material expansion device used in this method. An end side of plate material for press forming is restricted by blank holding rollers, and pressure is applied to a middle location in the part that is restricted by a pressure roller. In this state, the plate material is transported in a rotating direction of the rollers being driven to continuously bend and extend the section receiving pressure. This bent and extended section is flattened with a flattening roller to obtain blank material wherein an end part is expanded.

Provided is a technology capable of suppressing an edge crack occurring due to stretch flange deformation without being constrained by a target pressed component shape. The technology includes two-stage cutting processing of, when it is estimated that there is concern about risk of occurrence of an edge crack due to stretch flange deformation on an edge of a material (1) to be pressed in press forming, performing twice cutting processing on an edge including at least a site where there is concern about risk of occurrence of the edge crack as pre-processing for press forming in which there is concern about risk of occurrence of the edge crack. In the two-stage cutting processing, cutting to form a partial, beam-shaped overhang portion at a position including a site where there is concern about risk of occurrence of the edge crack is performed in the first cutting and the overhang portion is cut in the second cutting.

Provided is a technology capable of suppressing an edge crack occurring due to stretch flange deformation without being constrained by a target pressed component shape. The technology includes two-stage cutting processing of, when it is estimated that there is concern about risk of occurrence of an edge crack due to stretch flange deformation on an edge of a material (1) to be pressed in press forming, performing twice cutting processing on an edge including at least a site where there is concern about risk of occurrence of the edge crack as pre-processing for press forming in which there is concern about risk of occurrence of the edge crack. In the two-stage cutting processing, cutting to form a partial, beam-shaped overhang portion at a position including a site where there is concern about risk of occurrence of the edge crack is performed in the first cutting and the overhang portion is cut in the second cutting.

A pressing technology for reducing tensile residual stress generated on a sheared edge face of a metal sheet after press forming in order to prevent occurrence of a delayed fracture on the sheared edge face. A pressed component manufacturing method for manufacturing a pressed component by press-forming a metal sheet having a sheared edge face includes a first press forming step in which it is estimated that tensile residual stress is generated in a direction along the sheared edge on a portion of the sheared edge face of the metal sheet after die release, in which the method includes, as a subsequent step to the first press forming step, a tensile residual stress relaxation step of bulging, in the sheet thickness direction, a region that includes at least a site on a sheared edge face where it is estimated that the tensile residual stress is generated.

A pressing technology for reducing tensile residual stress generated on a sheared edge face of a metal sheet after press forming in order to prevent occurrence of a delayed fracture on the sheared edge face. A pressed component manufacturing method for manufacturing a pressed component by press-forming a metal sheet having a sheared edge face includes a first press forming step in which it is estimated that tensile residual stress is generated in a direction along the sheared edge on a portion of the sheared edge face of the metal sheet after die release, in which the method includes, as a subsequent step to the first press forming step, a tensile residual stress relaxation step of bulging, in the sheet thickness direction, a region that includes at least a site on a sheared edge face where it is estimated that the tensile residual stress is generated.

A domer station having a domer assembly, a housing assembly, and a stacked piston assembly is provided. The domer assembly is movably disposed within a domer body passage located in the housing assembly and structured to move between a forward, first position and a retracted, second position. The stacked piston assembly includes a plurality of pistons, preferably three pistons, disposed in series and a pressure supply. The pistons are disposed behind the domer in pressure chambers. The pistons have a constant pressure applied thereto and are biased towards the domer. The pistons are, however, each restrained by a stop and do not contact, or operatively engage, the domer when the domer is in the domer first position.