Production method for producing a press-formed product
A method for producing a press-formed product that includes a pair of flat sections and a bend section that connects the flat sections, in which a bending radius of the bend section is R 2 and an interior angle formed by the pair of flat sections is θ 2 , includes the steps bellow. In the first forming step, an intermediate formed product including a bend section in which a bending radius is R 1 and an interior angle is θ 1 is formed. In the second forming step, a portion of a bend section of the intermediate formed product is formed into the bend section of the press-formed product. R 1 , θ 1 , R 2 and θ 2 satisfy the conditions of Formulae (1) to (3) below: 1.05< A 1 /A 2 (1); 1.0< R 1 /R 2 (2); A 1 /A 2 <6.0/( R 1 /R 2 ) (3), where, A 1 , A 2 represents the supplementary angle of the interior angle θ 1 , θ 2 , respectively.
1. A production method for producing a press-formed product, the press-formed product including a pair of flat sections and a bend section connecting the pair of flat sections, in which a bending radius of the bend section is R 2 and an interior angle formed by the pair of flat sections is θ 2 , the production method comprising:
a starting material preparation step of preparing a metal plate having a tensile strength of 590 MPa or more;
a first forming step of subjecting the metal plate to press working using a first die assembly to form an intermediate formed product having a bend section with a bending radius of R 1 (mm) and an interior angle of θ 1 (°) at a portion corresponding to the bend section of the press-formed product; and
a second forming step of subjecting the intermediate formed product to press working using a second die assembly to form the press-formed product having the bend section with the bending radius of R 2 (mm) and the interior angle of θ 2 (°) at a portion of the bend section of the intermediate formed product;
wherein the bending radius R 1 and the interior angle θ 1 of the intermediate formed product and the bending radius R 2 and the interior angle θ 2 of the press-formed product satisfy conditions of Formulae (1) to (3) below:
1.05< A 1 /A 2 (1)
1.0< R 1 /R 2 (2)
A 1 /A 2 <6.0/( R 1 /R 2 ) (3);
where, in the above Formulae, A 1 (°) is a supplementary angle of the interior angle θ 1 of the intermediate formed product, which is represented by Formula (A) below, and A 2 (°) is a supplementary angle of the interior angle θ 2 of the press-formed product, which is represented by Formula (B) below:
A 1 =180−θ 1 (A)
A 2 =180−θ 2 (B).
2. The production method for producing a press-formed product according to claim 1 , wherein:
the bending radius R 1 and the interior angle θ 1 of the intermediate formed product and the bending radius R 2 and the interior angle θ 2 of the press-formed product satisfy conditions of Formulae (4) and (5) below in place of Formulae (2) and (3):
1.5< R 1 /R 2 (4)
A 1 /A 2 <3.5/( R 1 /R 2 ) (5).
3. The production method for producing a press-formed product according to claim 1 , wherein:
in the first forming step, a punch and a die are used as the first die assembly, and
in the second forming step, a punch and a die are used as the second die assembly.
4. The production method for producing a press-formed product according to claim 3 , wherein:
in the second forming step, when performing press working, the intermediate formed product is restrained and positioned by a die pad provided in the die and an inner pad provided in the punch.