Salt bath quenching of construction parts treated with a nitriding bath
AssigneeDeutsche Gold- und Silber-Scheideanstalt vormals Roessler
InventorsHelmut Kunst, Christian Scondo
Life of this patent
Estimating the term…
Abstract
Iron and steel construction parts which have been treated in a high cyanate, low cyanide or cyanide free nitriding salt bath or in other cyanide containing salt baths are tempered in a bath comprising an alkali metal hydroxide. There also can be present in the cooling bath 2 to 20 weight % of an alkali nitrate.
Claims12
In a process of tempering an iron or steel part that has been treated initially in (1) a low cyanide, high cyanate nitriding bath, (2) a cyanide free, high cyanate nitriding bath or (3) a high cyanide nitriding or carburiding bath, the improvement comprising taking the part containing entrained cyanide or cyanate from said bath and placing it in a tempering bath having a temperature of 190.degree. to 580.degree. C and keeping the part in the tempering bath until the entrained cyanide or cyanate is substantially completely decomposed, said bath consisting of at least one alkali metal hydroxide with 2 to 20% of at least one alkali metal nitrate based on the total weight of the tempering bath.
Dependencies are inferred from the claim text.