HOT FORMING METHOD AND APPARATUS OF GALVANIZED STEEL MATERIAL, INFRARED FURNACE AND HOT-FORMED ARTICLE OF GALVANIZED STEEL MATERIAL

摘要

PROBLEM TO BE SOLVED: To prevent intercrystalline cracks due to zinc heated to a predetermined temperature range as much as possible in the hot forming of a galvanized steel material.SOLUTION: A hot forming method of a galvanized steel material includes: a step preparing the galvanized steel material as a blank; a step heating the first region of the blank to a quenching temperature or higher and heating the second region of the blank to a non-quenching temperature; a step where a transition region being inevitably heated to a predetermined temperature range related to intercrystalline cracks due to zinc is forcedly cooled and the temperature of the transition region is made lower than the predetermined temperature range and higher than the temperature of the second region in the vicinity of a boundary of the first region and the second region; and a step performing the hot forming of the blank having temperature distribution set by heating or forced cooling.SELECTED DRAWING: Figure 1