During cladding an austenitic layer on low-carbon and medium-alloyed steels, the properties of the heat-affected zone, along with the resistance of the surface layer to resist corrosion, largely determine the performance and durability of the surfaced product. The work is devoted to the study of the dependence of the properties of the heat-affected zone during cladding of power equipment with austenitic materials on the parameters of the control mechanical impacts on the strip electrode and determination of their optimal range, which ensures high values of the mechanical properties of the deposited layer.

The reasons for the decrease in the operational resistance of high-pressure metal hoses made of austenitic steels are considered. The main cause of damage to metal high-pressure hoses was revealed, namely, the low performance of the metal protective braiding under the influence of an unfavorable environment. It has been established in the work that in the initial state the wire made of AISI 201 steel has a high strength (σ0.2= 1370 MPa and σT= 1650 MPa) and has relatively low plastic characteristics (δ = 15 % и ψ = 40 %), since up to 40–60% deformation martensite is present in its structure. The resistance of steels of the austenitic class AISI 201 and AISI 316 to intergranular corrosion has been investigated. The effect of heat treatment on the mechanical and plastic properties of wire samples of ø made of AISI 201 steel has been investigated. Optimal heat treatment modes have been determined that increase the durability of the braid in an unfavorable environment and, consequently, the operational durability of metal hoses in general.

Welded flexible compensating elements made of austenitic stainless steels, such as metal hoses and bellows expansion joints, operate in a complex stress state; therefore, almost all corrosion damage of these products occurs in a stressed state. In addition, in welded joints, defects are possible associated with elastic-plastic deformations and stresses arising in the manufacturing process. Paper considers the defects of welded joints of multilayer bellows expansion joints made of stainless steels AISI 304 and AISI 316 types. The influence of the parameters of the argon tungsten electrode welding mode, with or without filler wire, on the mechanical characteristics of welded joints was studied. Mechanical tests of samples of welded joints were carried out on a tensile testing machine. The optimal range of variation of the parameters of the welding mode has been established, in which the plastic characteristics of the welded joints have maximum values. A metallographic study of the microstructure of welded joints of metal hoses and bellows expansion joints was carried out. The influence of the content of nonmetallic inclusions in the material of products on the conditions of melting and crystallization of the weld pool, contributing to the appearance of pores and hot cracks in the metal of the weld and the heat affected zone, has been established. To reduce the influence of the content of non-metallic inclusions in the weld metal and the heat-affected zone on the conditions of melting and crystallization of the weld pool, it is recommended to carry out preliminary heat treatment of the austenitic steel strip.

Finishnoye plazmennoye uprochneniyenanotekhnologiya (k 25-letiyu sozdaniya) [Final plasma hardeningnanotechnology (to the 25th anniversary of its creation)]. Tekhnologii uprochneniya, naneseniya pokrytiy i remonta: Teoriya i praktika-Technologies of hardening, coating and repair: Theory and practice, 2012, vol. 2, pp. 344-366. (Rus.) 13. Samotugin S.S, Mazur V.A. Plazmennoye mikro-i nanostrukturirovaniye poverkhnosti instrumental'nykh staley [Plasma microand nanostructuring of the surface of tool steels]. Uprochnyayushchiye tekhnologii i pokrytiya-Strengthening technologies and coatings, 2013, no. 4, pp. 29-37. (Rus.) 14. Samotugin S.S., Samotugina Yu.S., Khristenko O.A. Nanotekhnologii v mashinostroyenii: plazmennoyemodifitsirovaniyerez'bonareznogoinstrumenta [Nanotechnologies in mechanical engineering: plasma modification of thread-cutting tools].

The paper investigates the effect of welding mode parameters on the uniformity of the deformation capacity of AISI 316 austenitic steel samples, namely, the influence of the welding current and purging gas consumption on the samples’ ability to perceive the force of cold cupping. Punch diameters of 3 and 8 mm were employed for the Erikson test to establish the dependence of the purge gas flow rate on the depth of the hole before the formation of cracks. The conducted metallographic studies confirmed an increase in the homogeneity of the dendritic structure in the weld zone due to the redistribution of heat input, as well as the absence of uneven grains and a decrease in the spread of grain sizes, which were in the range of 0.068–0.045 mm. The study resulted in determining the optimal range of technological parameters for the manufacture of flexible expansion elements to ensure their high operational properties.