Tube hydroforming is currently a well-established production technology in the automotive industry, used for the production of exhaust, chassis, and subframe components. Stainless-steel alloys are often used in exhaust components in particular. However, due to the limited formability of ferritic stainless steels, such as 1.4509, these are usually produced in several forming stages with interposed annealing processes. These process chains are very long and energy intensive, and thus cost intensive. The process chains will have to be shortened and energy consumption reduced if the production process is to be made more resource- and cost-effective.This paper demonstrates one possibility for the shortening of process chains. Temperature-supported forming has been used successfully to improve the forming capacity of ferritic stainless steel 1.4509 significantly. The essential challenges for the implementation of hydroforming processes at increased forming temperatures are the choice of forming medium, the heating of the component and the management of the process. Based on required temperatures of up to 1100 °C, the dies themselves cannot be heated to the forming temperature, unlike in the case of aluminium and magnesium forming. Therefore, the basis for a reliable temperature-supported forming process is a system and die technology designed specifically for the process.
展开▼
