Hot pressing method and hot pressing system

Abstract

In a hot pressing method for manufacturing a press-formed article (8, 9) by hot pressing a blank material (7) using a mold (2, 3) including a punch (21, 31), a die (22, 31) and an inner pad (23, 33) which is propelled so as to protrude toward the die (22, 32), a surface temperature T of the inner pad (23, 33) is cooled to a temperature satisfying the following formula, with 100 DEG C as an upper limit, by causing a refrigerant to flow through a refrigerant pathway (233, 333) after the press-formed article (8, 9) has been removed from the mold (2, 3) until the next blank material (7) is set inthe mold (2, 3). T<= 100 * (2.3 / t) *(h / 100) *(lambda / 30) *(W / 2)* S T: Surface temperature (DEG C) of inner pad (23, 33) h: Pressing direction dimension (mm) of inner pad (23, 33) t: Thickness (mm) ofblank material (7) lambda: Thermal conductivity (W / mK) of inner pad (23, 33) W: Volume ratio (mm3 / mm3) of refrigerant pathway within inner pad (23, 33) S: Flow rate (mm / sec) of refrigerant in refrigerant pathway (233, 333).

Description

technical field [0001] The present invention relates to a hot stamping method and a hot stamping system for performing the hot stamping method. Background technique [0002] For example, structural parts for automobiles are required to reduce weight while maintaining or improving mechanical strength from the viewpoint of improving fuel consumption and protecting passengers. In general, materials with high mechanical strength have low formability during forming processes such as press processing, making it difficult to process them into complex shapes. As a processing method for improving the formability of a material having a relatively high mechanical strength, as described in Patent Document 1 and Patent Document 2, materials (blanks, pre-press molded products) heated by a press molding die can be cited. The so-called hot stamping method (also sometimes called hot stamping method, hot pressing method, die quenching method, etc.) that performs forming and rapid cooling. A...

AI Technical Summary

Problems solved by technology

However, such an inner pad is small in volume compared to the main body of the mold, so the temperature tends to rise

Then, when hot stamping is performed with the temperature of the inner pad raised, the degree of quenching of the produced stamped product may be lowered and the mechanical strength may be lowered.

In particular, when hot stamping is repeated to manufacture a plurality of press-formed products, the temperature of the inner pad is maintained at an elevated state, so the mechanical strength of the produced press-formed products may decrease

Images