Feasibility study on direct flame impingement heating applied for the solution heat treatment, forming and cold die quenching technique

The solution heat treatment, forming and cold die quenching (HFQ) process has been developed and adopted for forming high strength complex-shaped components of light alloys in the automotive industry. In order to exploit and increase the competitiveness of this technology, production cycle time and manufacturing costs need to be reduced to enable high productivity and energy efficiency. This can be realised by reducing the cycle time for heating a metallic sheet to its solution heat treatment temperature during the HFQ process, and by decreasing post ageing time. Rapid heating methods are capable of providing a solution to be integrated into this novel forming technique of HFQ. This paper presents feasibility study on the adoption of the direct flame impingement (DFI) heating method that has a high potential for non-ferrous blanks to achieve higher heating rate in HFQ processes, compared to convection heating in a conventional furnace. The adaptability of DFI heating for HFQ process has been validated, in terms of capability of high heating rate, quality of surface layer examination and lap-shear strength measurement of bonded samples.