Metal parts and method of producing them

摘要

The invention relates to metal parts, in particular thread-guiding parts in textile machines. Apart from the actual metal thread guides, these comprise, in particular, needles on knitting machines. The invention also relates to a method of producing the metal parts, which method can also be used to treat tools and tool parts. The object of the invention is to provide metal parts by means of a continuous and economical method. Said metal parts are hard and wear-resistant while having a particularly smooth surface, and they do not acquire cracks and notches even on prolonged use. According to the invention, the surface of the base material of the metal parts underneath an electroplated coating is at least equally as hard as the coating but has about the same coefficient of thermal expansion as the base material. The method of producing them is to prefabricate the parts until the final base material shape is obtained and to chemically alter them by diffusing in an element of main group 3 of the periodic system of elements from a gas phase. This treatment is followed by a polishing operation, which is preferably electrochemical and the parts are then provided with a thin electroplated coating.