Low pressure carburizing of large gears in single chamber vacuum oil quenching furnace
Some thermochemical treatment applications may require some furnace adaptation, heavy engineering modifications or even a new furnace concept and design in order to meet customer’s specifications, his production capacity and last but not least, his budgetary constraint.
This case study relates to the carburizing of large gears for railway train bogies in a single chamber vacuum oil quenching furnace. Besides the usual metallurgical criteria of carburizing thickness, core and surface hardness and microstructures, customer is strongly expecting a reduction of distorsion to avoid or to reduce mechanical reworking. In the presentation, we will go through the different technologic choices to meet these specifications, including the choice of furnace typology which influences the transition phase between hot zone and oil bath but also the selection of quenching oil and the choice of fixtures design.