Fractional Cooling Strategy of the Hot-Stamping Process and Its Influence on Formability and Mechanical Properties of Ultra-High-Strength Steel Parts

作     者：Xian-Hong Han Cheng-Long Wang Si-Si Chen Jun Chen 

作者机构：Department of Plasticity Technology School of Materials Science and Engineering Shanghai Jiao Tong University SAIC General Motors Co. Ltd 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2019年第32卷第3期

页      面：343-351页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：supported by the National Natural Science Foundation of China under Grants 51775336 and U1564203 the Shanghai Pujiang Program under Grant No. 17PJD019 

主　　题：Hot-stamping Fractional cooling Forming temperature Formability 

摘      要：The effects of forming temperature on the formability and product properties of hot-stamping boron steel B1500HS were investigated. Based on the fractional cooling strategy, boron steel sheets were heated to achieve full austenitization before they were removed from the furnace and cooled to the forming temperature using different cooling methods. Subsequently,they were simultaneously press-formed and quenched inside the tool until the martensitic transformation was finished. A series of thermal tensile tests were conducted to study the effects of forming temperatures on the stamping performance indices, including elongation, yield ratio, and hardening exponent. Then, the mechanical properties and microstructures of the hot-stamped products were characterized. Finally, an irregular part was formed using different fractional cooling strategies, while its formability and springback phenomena were discussed. The results show that using a fast-cooling method to reach 650 °C as the forming temperature optimizes the formability of the tested B1500HS boron steel. The best mechanical properties and smallest springback values were achieved using this optimal strategy.