The urgency of heat treatment of samples of maraging steel obtained by direct laser deposition from steel powder 06Cr15Ni4CuMo is considered. The structural features and properties of 06Cr15Ni4CuMo steel samples after direct laser deposition and heat treatment are studied. The work is devoted to research into the influence of thermal processing on the formation of structure and the mechanical properties of deposit samples. Features of formation of microstructural components by means of optical microscopy are investigated. Tests for tension and impact toughness are conducted. As a result, it was established that the material obtained by the direct laser deposition method in its initial state significantly exceeds the strength characteristics of heat treatment castings of similar chemical composition, but is inferior to it in terms of impact toughness and relative elongation. The increase in relative elongation and impact toughness up to the level of cast material in the deposit samples is achieved at the subsequent heat treatment, which leads to the formation of the structure of tempered martensite and reduction in its content at two-stage tempering in the structure of the metal. The strength of the material is also reduced to the level of cast metal.

In this work, the critical fracture stresses during spalling of high-strength steel 09CrNi2MoCu samples obtained by direct laser deposition (DLD) were measured under shock compression of up to ~5.5 GPa. The microstructure and mechanical properties of DLD steel samples in the initial state and after heat treatment were studied and compared to traditional hot rolled one. The microstructural features of steel before and after heat treatment were revealed. The heat treatment modes of the deposit specimens on their strength properties under both static and dynamic loads have been investigated. The spall strength of the deposited specimens is somewhat lower than the strength of steel specimens after hot rolling regardless of their heat treatment. The minimum elastic limit of elasticity is exhibited by the deposit specimens. After heat treatment of the deposit samples, the elastic limit increases and approximately doubles. Subsequent heat treatment in the form of hardening and tempering allows obtaining strength properties under Hugoniot loads in traditional hot-rolled products.

Direct laser deposition technology is used for the manufacture of large-size products with complex geometries. As a rule, trial samples with small dimensions are made to determine the deposition parameters. In order for the resulting products to have the required performance characteristics, it is necessary to minimize the number of internal macrodefects. Non-fusion between the tracks are defects that depend on the technological mode (power, speed, track width, etc.). In this work, studies have been carried out to determine the power level at which non-fusion is formed, dwell time between the tracks on the model samples. This paper considers the issue of transferring the technological parameters of direct laser deposition from model samples to a large-sized part, and describes the procedure for making model samples.