HOT FORMING PARTS HAVING STRENGTH DISTRIBUTION AND METHOD FOR MANUFACTURING THE SAME

摘要

PURPOSE: A hot-formed product having a dual-strength zone and a manufacturing method thereof are provided to form areas with different strength and properties in a single part by cooling a part of blank after heating the blank in whole. CONSTITUTION: A method for manufacturing a hot-formed product having a dual-strength zone is as follows. The whole part of blank for hot forming is heated over the Ac3 transformation point. One or more parts of the firstly heated blank are cooled below the Ac3 transformation point. The partially cooled blank is hot formed to obtain a formed product. The formed product is cooled below the martensitic transformation start temperature. [Reference numerals] (AA) Stress(MPa); (BB) Distortion