Preheating of e.g. sheet for hot-pressing in automobile industry, employs heat released by cooling- and deformation processes, to preheat workpieces before forming

摘要

Heat released by the workpiece cooling process is used to preheat the workpiece blanks before forming them. Preheating takes place before the workpiece enters a furnace (7). Cooling is accelerated by a flow of air brushing past the workpiece during forming. This air (6) is used to pre-heat the workpiece. Preheating energy is also obtained from coolant used in the forming die. Both these sources of pre-heating are combined. Fans (17) are used to promote airflow from ambient air entering openings at the base of the plant. This air is returned by a thermal recycling line (5) to the preheater (4) ahead of the continuous furnace plant (7, 8, 9, 23). Heat is recovered from the forming machine coolant, using an indirect heat exchanger (24), and sent as a hot airflow to the preheater. An independent claim is included for plant used in the process.