Antiseizing Properties of Titanium Alloys under Different Chemical and Heat Treatment

Abstract

Chemical and heat treatment (CHT) of titanium alloys for preventing their failure upon friction is based on general principles designed for ferroalloys but has its own characteristic properties related to the different chemical nature of these metals. The development of antiseizing CHT of ferroalloys was made based on the conception that a decrease in friction between metal surfaces and prevention of seizure upon friction was achieved by modifying friction surfaces with chemical compounds. As a result friction surfaces have lower resistance to shear, microcontact rupture upon friction is localized and is not followed by the tearing out of depth metal.^(1,2) From this conception it is stemmed that to obtain a high antiseizing effect chemical interaction between active compounds entering into the composition of salt baths used for CHT (or into the composition of material lubrication) and friction metal surfaces ⁽³⁾ is necessary. In accordance with this conception the choice of chemical compounds for chemical and heat treated titanium alloys is made with the use of the method of thermography applied advantageously upon the development of sulphurization methods for ferroalloys.⁽³⁾ Chemical interaction was determined by the appearance of characteristic current on the heating curve of a differential thermocouple.