Method and apparatus for manufacturing metal sections

Claim 1

A method of manufacturing metal sections, comprising: hot-forging a substantially quadrangular cross-section starting material in the longitudinal direction thereof into a blank having a concave portion therein in the middle of the long sides of the cross-section and upstanding flange portions at the ends of the long sides of the cross-section by applying, while moving the starting material in the direction of the length, forging pressure to the opposite surfaces defining the long sides of the cross-section and along a length of the starting material, which forging pressure is applied substantially perpendicular to the longitudinal axis of the starting material and being uniform from one end of the length to near the other end, and then gradually decreasing to said other end, while at the same time applying further forging pressure to the opposite surfaces of the starting material defining the end surfaces of the cross-section and in a direction substantially perpendicular to the longitudinal axis of the starting material, said further pressure being sufficient for at least preventing material of the starting material from flowing toward the ends of the cross-section of the starting material, repeating the application of forging pressures on the succeeding lengths of the starting material and applying the uniform forging pressure to the portion of the preceeding length to which the gradually decreasing forging pressure has been applied for forming a substantially uniform cross-section throughout the entire length of the blank; and hot rolling the blank into a generally H-shaped metal section having the desired cross-section.

Claim 2

A method of manufacturing metal sections, comprising: hot-forging a substantially quadrangular cross-section starting material in the longitudinal direction thereof into a blank having a concave portion therein in the middle of the long sides of the cross-section and upstanding flange portions at the ends of the long sides of the cross-section by applying, while moving the starting material in the direction of the length, forging pressure to the opposite surfaces defining the long sides of the cross-section and along a length of the starting material, which forging pressure is applied substantially perpendicular to the longitudinal axis of the starting material and being uniform from one end of the length to near the other end, and then gradually decreasing to said other end, while at the same time applying further forging pressure to the opposite surfaces of the starting material defining the end surfaces of the cross-section and in a direction substantially perpendicular to the longitudinal axis of the starting material, said further pressure being sufficient for at least preventing material of the starting material from flowing toward the ends of the cross-section of the starting material, repeating the application of forging pressures on the succeeding lengths of the starting material and applying the uniform forging pressure to the portion of the preceeding length to which the gradually decreasing forging pressure has been applied for forming a substantially uniform cross-section throughout the entire length of the blank; and hot rolling the blank into a generally H-shaped metal section having the desired cross-section.

Claim 8

An apparatus for manufacturing metal sections comprising: a forging press for hot forging a substantially quadrangular cross-section starting material into a blank having a substantially H-shaped cross-section resembling that of the desired product, said forging press having means for positioning the starting material and means for moving tools in a direction toward opposite surfaces of the starting material in position in said positioning means and which surfaces define the longer sides of the cross-section of the starting material, said moving means moving said tools substantially perpendicular to the longitudinal axis of the starting material in said positioning means, and elongated forging tools on said moving means extending in the direction of the length of the starting material when it is positioned in said positioning means, said tools each having a pressure applying face with a width less than the width of the opposite surfaces of the starting material which define the longer sides of the cross-section of the starting material and a uniform cross-sectional profile from one end to near the other end and having the portion from near the other end to the other end tapered at least in a direction for gradually reducing the forging pressure applied to the starting material by the forging tool; said forging press having further means for moving forging tools in a direction toward the opposite surfaces of the starting material in position in said positioning means which surfaces define the end surfaces of the cross-section of the starting material, said further means being capable of applying a pressure which is at least sufficient for preventing material of the starting material from flowing toward the ends of the cross-section of the starting material; means for moving said starting material and said forging press relative to each other in a direction of elongation of said forging tools and from said tapered portion toward said uniform cross-section portion and through a distance equal to the length of the uniform cross-section profile along said forging tool; and hot rolling means downstream of said forging press for hot rolling the blank into a generally H-shaped metal section having the desired cross-sectional shape.

Claim 9

An apparatus for manufacturing metal sections comprising: a forging press for hot forging a substantially quadrangular cross-section starting material into a blank having a substantially H-shaped cross-section resembling that of the desired product, said forging press having means for positioning the starting material and means for moving tools in a direction toward opposite surfaces of the starting material in position in said positioning means and which surfaces define the longer sides of the cross-section of the starting material, said moving means moving said tools substantially perpendicular to the longitudinal axis of the starting material in said positioning means, and elongated forging tools on said moving means extending in the direction of the length of the starting material when it is positioned in said positioning means, said tools each having a pressure applying face with a width less than the width of the opposite surfaces of the starting material which define the longer sides of the cross-section of the starting material and a uniform cross-sectional profile from one end to near the other end and having the portion from near the other end to the other end tapered at least in a direction for gradually reducing the forging pressure applied to the starting material by the forging tool; said forging press having further means for moving forging tools in a direction toward the opposite surfaces of the starting material in position in said positioning means which surfaces define the end surfaces of the cross-section of the starting material, said further means being capable of applying a pressure which is at least sufficient for preventing material of the starting material from flowing toward the ends of the cross-section of the starting material; means for moving said starting material and said forging press relative to each other in a direction of elongation of said forging tools and from said tapered portion toward said uniform cross-section portion and through a distance equal to the length of the uniform cross-section profile along said forging tool; and hot rolling means downstream of said forging press for hot rolling the blank into a generally H-shaped metal section having the desired cross-sectional shape.