August 2023 Volume 5

FORGING RESEARCH

Benefits:

• Quick heating • Accurate and easily repeatable • Safe since no flame is involved • Longer life of dies as accurate heating is ensured. • Scrap significantly reduced as no stopping of production is required. Limitations: • Comparatively costly than other heating methods. • Separate mounting required in the press increasing the overall cost. 2.3.2.4 Furnace heating The dies are heated in the furnace to the desired temperatures or slightly above. These heated dies are then placed in the press for further operation. The temperatures are measured in the furnace as well as before the operation starts to maintain the uniformity of the temperature to perform the operation. The extra heating is done to compensate the loss of heat that occurs during transfer of dies from furnace to the press. Figure 2-9 shows an example of furnace heating [27].

Figure 2-6. Prototype stand for induction heating of the tools

Figure 2-7: Gas burners

Benefits: • Comparatively better heating is achieved.

• Initiation of forging operation is possible immediately after the heating and no scrap is generated at the beginning of the operation. Limitations: • During the heating process, the system is kept idle, affecting the process efficiency. • Long heating time, uncontrollable heating temperatures. • Frequent reheating for production of batch of forging. And the process is stopped for every reheat treatment. • Loss of heat to the environment as well. 2.3.2.3 Induction heating An induction heating system consists of an induction power supply for converting line power to an alternating current and delivering it to a work-head, and a work coil for generating an electromagnetic field within the coil. The workpiece is positioned in the coil as seen in Figure 2-8 such that this field induces a current in the work piece, which in turn produces heat [26]. Induction produces an electromagnetic field in a coil to transfer energy to a work piece to be heated. When the electrical current passes along a wire, a magnetic field is produced around that wire. Induction heating can achieve the temperatures ranging from 100C to 3000C.

Figure 2-9: Furnace Heating

Benefits: • Uniform heating is done. • Higher temperatures can be achieved. • Fast heating. Limitations: • Temperature loss while moving from furnace to press.

• Operational difficulty. • Operational time losses

Figure 2-8: Induction Heating

FIA MAGAZINE | AUGUST 2023 76