Heat treatment of tool steels usually requires high flexibility combined with small lots of parts. Seal quench furnaces, executed with a single heating chamber, meet this demand. A single-chamber furnace, executed with a pre-chamber, is used both for loading and unloading and also for oil quenching or gas cooling.
Methanol can be directly fed into the furnace and is evaporated and cracked in the furnace, forming H2 and CO with a ratio of 2 to 1. Evaporation or cracking of methanol can be done via an external heater, too. If the cracked methanol is diluted with the right amount of nitrogen, the composition of an endothermic gas can be matched. For hardening of tool steels, a higher dilution of the atmosphere can be done very easily by changing the correlation between nitrogen and methanol feed.
For more information, click on the link below (subscription required). Then scroll to Figure 5.
R. Schneider ; R. Mesquita ; H. Altena ; T. Müller ; P. Seemann,Processes and Furnace Equipment for Heat Treating of Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958
