Keyword: «heat treatment»

In this paper, a study of structural transformations of 14G2SAF pipe steel during welding, changes in its strength and ductility characteristics when simulating real thermal cycles under different ambient temperature conditions is carried out. The most optimal intervals of cooling rates were selected experimentally.

Extremely low operating temperatures and difficult mining and geological conditions for open mining of diamonds, gold, coal by industrial organizations require large-scale earthmoving works, which requires significant material costs for the purchase and supply of working bodies of various mining equipment, such as bulldozer ripper crowns, teeth and bucket tips for excavators and loaders. Currently, these working bodies of mining equipment are 90% produced and purchased from foreign companies. But the difficult global situation associated with the imposition of sanctions on the supply of spare parts for imported equipment requires the development of new scientific solutions for the creation of import-substituting technologies for the production of working bodies of mining machinery. Therefore, scientific research of the service properties of materials of the working bodies of mining machinery of imported manufacturers, is also a necessary factor for the accelerated development of import-substituting technologies.

After heat treatment, the ratio of hydroxyl and carboxyl groups, according to IR spectra, both in samples of natural nanodiamonds and in nanodiamonds obtained by detonation synthesis, decreases. An increase in the amount of carboxyl groups on the surface of nanodiamonds after heat treatment in air indicates the oxidation of functional groups under experimental conditions. In the IR spectra of nanodiamonds after heat treatment, the bands in the absorption region of the diamond lattice become more distinguishable, which is explained by the partial purification of the diamond crystalline core from the graphite-like shell. In the IR spectra of natural nanodiamonds after heat treatment, bands appear in the absorption region of nitrogen defects of types A and B, which makes it possible to attribute the sample under study to type I-AB.