Method for cooling metal parts having undergone a nitriding/nitrocarburising treatment in a molten salt bath, unit for implementing said method and the treated metal parts

摘要

Before the end of the treatment of metal parts in a molten salt bath nitriding/nitrocarburizing station, a chamber, arranged so that the oxygen contained in the chamber can be discharged in order to create an inert atmosphere, is filled with a refrigerant in liquid form and with a strong capacity for volume expansion as it evaporates. All the parts treated are transferred into the chamber. The chamber is closed, and the parts are left in the chamber for a preset length of time to reach a temperature at which the salt congeals and forms a protective barrier. The parts are then removed and subjected to a rinsing operation.

主权项

1. A method of cooling metal parts that have been subjected to a molten salt bath nitriding/nitrocarburizing treatment in a treatment station, comprising:
arranging a cooling chamber in direct overlying relation with the treatment station, before an end of said treatment, filling the cooling chamber, With refrigerant in liquid form, volume expansion as the refrigerant evaporates discharging oxygen from the cooling chamber to create an inert atmosphere within the cooling chamber, transferring vertically all the treated parts from the treatment station directly into the inert atmosphere within the cooling chamber, closing the chamber, leaving the parts in the chamber for a preset length of time to reach a temperature at which salt congeals and forms a protective barrier, and removing the parts from the chamber and then subjecting the parts to a rinsing operation, whereby the cooling method results in parts exhibiting no trace of surface oxidation.