| 摘要 |
PROBLEM TO BE SOLVED: To propose a wall crack resistance evaluation method for a metal thin plate and an evaluation method for a lubricant capable of evaluating the wall crack resistance and lubricant of the metal thin plate by exactly and easily reproducing a wall crack in press molding using a model mold. SOLUTION: When a punch is pressed on the metal thin plate and molded into a cup shape, a die whose shoulder radius r (mm) satisfies r/t≤5.0 (t: mm), a cylinder punch whose shoulder radius R (mm) and punch diameter d (mm) satisfies 0.2≤R/d≤0.6 and surface roughness is arithmetic center line average roughness Ra and 0.1μm or more, and the metal thin plate whose blank diameter L (mm) satisfies 1.4≤L/d≤2.6 are used. (A crease holding force)/(a blank area) is formed as 0.98-4.90 MPa, the wall crack is generated under plane strain deformation, and the wall crack resistance of the metal thin plate is evaluated under the plane strain deformation by the maximum molding height to the generation of the crack. COPYRIGHT: (C)2003,JPO
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