Abstract: Undesired nitrites are formed during the treatment of salt bath nitrided structural components of iron and steel in nitrate containing cooling baths, and they must be removed from the washing water. The build-up of nitrites can be avoided by oxidizing the nitrite in the salt bath into nitrate by passing air into the cooling bath during off-times.

Abstract: Low cyanide nitriding salt baths which are composed of alkali cyanate and alkali carbonate and used for treating components made of steel and iron produce coatings on the surface of the component in some cases and can lead to problems in the use of the components. A satisfactory surface quality can be obtained from nitriding salt baths which additionally contain 0.5 to 100 ppm of selenium.

Abstract: To increase the corrosion resistance of nitrided structural parts made of iron materials which are useful for all types of iron and steel there is carried out an oxidation treatment in connection with the nitriding process. The oxidation treatment is carried out for 15 to 50 minutes in an oxidizing salt bath. The salt bath preferably consists of alkali hydroxides with 2 to 20% of alkali nitrates.

Abstract: There is provided a boriding agent for mass produced parts of ferrous and non-ferrous metals consisting essentially of a boron yielding material, activator, filler and water as a binder and containing in the boriding agent 2 to 8 weight % of pyrogenic silica.

Abstract: Portions of the surface area of metal workpieces are insulated in thermochemical treatment by covering the areas with a self-adhering textile tape having metal powder embedded in its adhesive layer.

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.

Abstract: Iron and steel are nitrided in a salt bath in a process favorable to the environment. The salt bath consists essentially of potassium cyanate, sodium cyanate, potassium carbonate, and sodium carbonate. Preferably, air flows through the bath. The bath preferably contains 25-57 weight % of cyanate calculated as cyanate ion, 0 to 30% alkali metal chloride and the balance carbonate and alkali metal ions. Preferably cyanide is omitted, but it can be present in an amount up to 5%. Without removing the waste salt, the bath is regenerated by adding melon, melam, or melem.