Press working apparatus

A press working apparatus comprising:

• a press machine having a pair of press dies for pressing a preheated metal slab having a thickness and being transferred in a feeding direction perpendicular to the thickness;
• said press dies being mutually opposing and arranged to press said metal slab in a direction parallel to the thickness of said metal slab;
• each said press die having a pressing surface facing a respective surface of said metal slab;
• said pressing surface of each said die having a predetermined length extending in said feeding direction of said metal slab;
• said pressing surface of each said die having a cross section perpendicular to said feeding direction of said metal slab, a shape of each said cross section changing stepwise along the feeding direction of said metal slab so as to have a predetermined sectional shape for forming said metal slab into a required sectional shape at a leading end of the pressing surface of each said die in the feeding direction;
• and
• a plurality of protrusions of punching said metal slab formed on said pressing surface of each said die, said protrusions being arranged in both the feeding direction and a direction transverse to the feeding direction in columns and rows of predetermined pitches, and diameters of said protrusions increasing in said rows in the feeding direction.

A press working apparatus comprising:

• a press machine having a pair of press dies for pressing a preheated metal slab having a thickness and being transferred in a feeding direction perpendicular to the thickness;
• said press dies being mutually opposing and arranged to press said metal slab in a direction parallel to the thickness of said metal slab;
• each said press die having a pressing surface facing a respective surface of said metal slab;
• said pressing surface of each said die having a predetermined length extending in said feeding direction of said metal slab;
• at least one said pressing surface having a cross section perpendicular to said feeding direction of said metal slab, a shape of said cross section changing stepwise along the feeding direction of said metal slab so as to have a predetermined sectional shape for forming said metal slab into a required sectional shape at a leading end of the pressing surfaces in the feeding direction;
• and
• at least one said pressing surfaces having a plurality of parallel slots extending transversely to the feeding direction, each of said slots having a width and a depth, the width decreasing in the feeding direction, the depth increasing in the feeding direction, and wherein at least one of the pressing surfaces is designed such that distance between the pressing surfaces decreases in the feeding direction.