Procedure for the obtaining of a protective layer resistant to chemical and mechanical attacks on an steel base body. (Machine-translation by Google Translate, not legally binding)

摘要

Procedure for obtaining a protective layer resistance to chemical and mechanical attacks on a steel base body, especially a brake pipe for vehicles, where the base body is first galvanized galvanically, to the zinc layer is provides, chemically, a chromate coating resistant to abrasion and scratches and then provided with a coating of synthetic material and heat treated; the process being characterized because, in a continuous passage, on the body endowed with a thin layer of copper, a layer of zinc of finely crystalline structure with high homogeneity is precipitated, from a sulfuric acid electrolyte, with current intensities between 40 and 100 a/dm2, electrolyte temperatures of 50-55ºc and high electrolyte flow, using organic-based additives; the chromium layer is produced on the galvanized base body from a chromic acid solution with a ph greater than 2, preferably in the presence of a reducing agent; the chromed base body is rinsed to remove the remains of the chromic acid solution and dried so that the water of crystallization contained in the chrome layer is not displaced; after drying, it is coated with a dispersion of fluorinated synthetic material; and heat treated at a temperature of at least 100º c. (Machine-translation by Google Translate, not legally binding)