Abstract: A structural member 10 includes a hat member 1 and a closing plate 2. The length LY of the tubular portion formed by the hat member 1 and the closing plate 2 is 6 or more times the height H of a pair of side walls 11 and 12. Each of the side walls 11 and 12 includes a high-strength portion 11A or 12A and low-strength portions 11B or 12B. The high-strength portion has a yield strength not less than 500 MPa. The low-strength portions have a yield strength of 60 to 85% of that of the high-strength portion. Each high-strength portion extends a distance not less than (?)H and not more than 3H as measured in the direction in which the ridges extend, and is provided such that the high-strength portions of the pair of side walls face each other. A pair of low-strength portions sandwich the associated high-strength portion.

Abstract: A structural member (10) includes: a hat member (1); and a closing plate (2). The hat member (1) includes: a top-surface portion (1a); a pair of side walls (1b) extending from both edges of the top-surface portion (1a); and flanges (1c). The closing plate (2) is in contact with the flanges (1c). Each of the side walls (1b) includes a low-strength portion (1s) extending from one edge of the side wall (1b) to a position at a distance Sh. The distance Sh is 20 to 40% of the height H of the side wall (1b). The yield strength of the low-strength portion (1s) is 60 to 85% of the yield strength of the side wall (1b) as measured at a position (1mid) of one-half of the height of the side wall (1b).

Abstract: A structural member 10 includes a hat member 1 and a closing plate 2. The length LY of the tubular portion formed by the hat member 1 and the closing plate 2 is 6 or more times the height H of a pair of side walls 11 and 12. Each of the side walls 11 and 12 includes a high-strength portion 11A or 12A and low-strength portions 11B or 12B. The high-strength portion has a yield strength not less than 500 MPa. The low-strength portions have a yield strength of 60 to 85% of that of the high-strength portion. Each high-strength portion extends a distance not less than (?)H and not more than 3H as measured in the direction in which the ridges extend, and is provided such that the high-strength portions of the pair of side walls face each other. A pair of low-strength portions sandwich the associated high-strength portion.

Abstract: A metal pipe includes a pair of side walls facing each other and having a height H, a top portion connected to an upper edge of each of the pair of side walls, and a bottom portion connected to a lower edge of each of the pair of side walls. The metal pipe has a length six times the height H of the side walls or more. Each side wall pair includes a high-strength portion and a pair of low-strength portions, the low strength portions sandwiching the high strength portion. A high-strength portion dimension is not less than ?H and not more than 3H as measured longitudinally of the metal pipe, the high-strength portions forming opposite portions of the side wall pairs. The low-strength portion yield strength is 60 to 85% of that of the high-strength portion, whose yield strength is not less than 500 MPa.

Abstract: A metal pipe 1 has a quadrangular cross section. The metal pipe 1 includes a pair of side walls 11 and 12 facing each other and having a height H, a top portion 13 connected to an upper edge of each of the pair of side walls 11 and 12, and a bottom portion 14 connected to a lower edge of each of the pair of side walls 11 and 12. The metal pipe 1 has a length six times the height H of the side walls 11 and 12 or more. Each of the pair of side walls 11 and 12 includes a high-strength portion 11A or 12A and a pair of low-strength portions 11B or 12B. Each high-strength portion 11A or 12A has a dimension not less than (?) H and not more than 3 H as measured in the longitudinal direction of the metal pipe, the high-strength portions forming opposite portions of the pair of side walls 11 and 12, each high-strength portion having a yield strength not less than 500 MPa.

Abstract: A structural member (10) includes: a hat member (1); and a closing plate (2). The hat member (1) includes: a top-surface portion (1a); a pair of side walls (1b) extending from both edges of the top-surface portion (1a); and flanges (1c). The closing plate (2) is in contact with the flanges (1c). Each of the side walls (1b) includes a low-strength portion (1s) extending from one edge of the side wall (1b) to a position at a distance Sh. The distance Sh is 20 to 40% of the height H of the side wall (1b). The yield strength of the low-strength portion (1s) is 60 to 85% of the yield strength of the side wall (1b) as measured at a position (1mid) of one-half of the height of the side wall (1b).

Abstract: The present invention provides a hot press molding method for molding a heated metallic plate (K) using a molding die (20, 60) comprising an upper die (21) and a lower die (20). According to the method, the heated metallic plate is arranged between the upper die and the lower die, the upper die and the lower die are brought together, and the metallic plate held between the dies is pressed. After the metallic plate is pressed, a refrigerant in the form of a liquid or mist is supplied via a plurality of supply holes provided to the lower die to a surface of the metallic plate held between the dies, and once the refrigerant has finished being supplied, a gas is sprayed onto the surface of the metallic plate via the plurality of supply holes. It is thereby possible to remove, with maximum speed, liquid refrigerant adhering to the metallic plate when the supply of liquid refrigerant is stopped.

Abstract: The present invention provides a hot press molding method for molding a heated metallic plate (K) using a molding die (20, 60) comprising an upper die (21) and a lower die (20). According to the method, the heated metallic plate is arranged between the upper die and the lower die, the upper die and the lower die are brought together, and the metallic plate held between the dies is pressed. After the metallic plate is pressed, a refrigerant in the form of a liquid or mist is supplied via a plurality of supply holes provided to the lower die to a surface of the metallic plate held between the dies, and once the refrigerant has finished being supplied, a gas is sprayed onto the surface of the metallic plate via the plurality of supply holes. It is thereby possible to remove, with maximum speed, liquid refrigerant adhering to the metallic plate when the supply of liquid refrigerant is stopped.