Annotation: This article considers the practical data on parts (specimens) manufacturing from powder metal material 316L using the innovative method of selective laser melting; the comparative study of the structure and physical and mechanical properties of 316L material, the combined influence of heat treatment and specimen orientation relative to the arrangement plate on the physical and mechanical properties and structure of specimens made of 316L alloy. Results are presented of the following: comparative study of the physical and mechanical properties and structure of specimens, manufactured using the selective laser melting technologies with horizontal and vertical placement relative to the arrangement plate; dependence of the ultimate strength and unit elongation on the annealing temperature. The possibility and suitability of the selective laser melting technology to manufacture parts and space-rocket hardware are evaluated. Experimental study of the specimens heat treatment conditions after selective laser melting enabled the definition of the optimal condition for the 316L alloy and have shown that heat treatment of the manufactured specimens under the heating at 1230 °С with the subsequent tempering at the temperature of 510 °С gives the homogeneous structure to the material of specimens made of alloy 316L, its dendritic structure, inherent in the specimen material in its initial condition, disappears after selective laser melting. Results of the mechanical tests of the obtained specimens have shown that the technology of selective laser melting provides development of products made of powder metal material 316L with optimal complex of physical and mechanical properties. It is shown that transition to the selective laser melting technology will enable production of the aerospace products, in particular geometrically-complex parts made of powder metal material 316L, in one technological cycle, excluding cutting, punching, refinement, cropping, welding, manufacturing of special tools or stamps

Annotation: Strength calculation example of the specific design bellows is taken to consider one of the possible approaches to the numerical simulation of the stress and strain state of the multilayer bellows. Proposed approach is based on the use of axial symmetry of the structure for transition from 3D calculation model to 2D one. Calculations take place in the elastoplastic setup, using the software package of the finite elements method. As an example of the proposed approach static and fatigue strength of the three-layer steel bellows of the Cyclone-4M fuel supply line are calculated. Calculation of the static strength of the bellows, loaded with internal pressure, showed that layer stresses achieve yield strength, at the same time preserving the bearing capacity of the structure. Results of the simulated change in the stress and strain state of the bellows per one cycle of the variable reloading were taken to find the amplitude of the plastic deformations in the most loaded area of the bellows, which allowed estimation of its fatigue strength in the conditions of lowcycle loading. Advantage of the proposed approach to the multilayer bellows strength evaluation is that it does not require large volumes of RAM and time to do the calculations.